tag:theconversation.com,2011:/global/topics/space-debris-8399/articlesSpace debris – The Conversation2023-12-12T13:22:22Ztag:theconversation.com,2011:article/2168082023-12-12T13:22:22Z2023-12-12T13:22:22ZScientists and space agencies are shooting for the Moon – 5 essential reads on modern lunar missions<figure><img src="https://images.theconversation.com/files/556958/original/file-20231031-19-egoy20.jpg?ixlib=rb-1.1.0&rect=72%2C21%2C4734%2C3293&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">The Moon, shot from Pakistan during a lunar eclipse. </span> <span class="attribution"><a class="source" href="https://newsroom.ap.org/detail/PakistanLunarEclipse/78b42ec6aa9f40218389cd06b938b1ff/photo?Query=moon&mediaType=photo&sortBy=&dateRange=Anytime&totalCount=41215&currentItemNo=5">AP Photo/Fareed Khan</a></span></figcaption></figure><p>The year 2023 proved a big one for lunar science. <a href="https://theconversation.com/indias-chandrayaan-3-landed-on-the-south-pole-of-the-moon-a-space-policy-expert-explains-what-this-means-for-india-and-the-global-race-to-the-moon-212171">India’s Chandrayaan-3 spacecraft landed</a> near the south pole of the Moon, a huge accomplishment for a country relatively new to the space scene, especially after its <a href="https://science.nasa.gov/mission/chandrayaan-2/">Chandrayaan-2 craft crashed</a> in 2019. </p>
<p>At the same time, NASA’s been gearing up for a host of Moon-related missions, including its <a href="https://www.nasa.gov/specials/artemis/">Artemis program</a>. In 2023, the agency gained nine signatories to the <a href="https://www.nasa.gov/artemis-accords/">Artemis Accords</a>, an international agreement for peaceful space exploration, for a total of 32 countries that have signed so far. </p>
<p>As Georgia Tech’s <a href="https://theconversation.com/returning-to-the-moon-can-benefit-commercial-military-and-political-sectors-a-space-policy-expert-explains-209300">Mariel Borowitz explains</a>, the U.S. now has widespread bipartisan political support for spacefaring – for the first time since the 1970s – and returning missions to the Moon is the first natural target. </p>
<p>Here are five stories that The Conversation U.S. has published over the past year about lunar exploration, including why people want to go back to the Moon, what Chandrayaan-3 found during its initial foray across the lunar surface and the ever-growing problem of lunar space junk. </p>
<h2>1. Why shoot for the Moon?</h2>
<p>Missions to the Moon <a href="https://theconversation.com/returning-to-the-moon-can-benefit-commercial-military-and-political-sectors-a-space-policy-expert-explains-209300">hold potential benefits</a> for a variety of sectors, including commercial, military and geopolitical. </p>
<p>“Ever since humans last left the Moon in 1972, many have dreamed about the days when people would return. But for decades, these efforts have hit political roadblocks,” <a href="https://scholar.google.com/citations?user=aESo-coAAAAJ&hl=en">wrote Borowitz</a>. “This time, the United States’ plans to return to the Moon are likely to succeed – it has the cross-sector support and the strategic importance to ensure continuity, even during politically challenging times.”</p>
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<iframe width="440" height="260" src="https://www.youtube.com/embed/ocDzndmmE8I?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">NASA is planning to return to the Moon with Artemis missions. This video describes where on the Moon it may land and how it will decide.</span></figcaption>
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<p>While some of these <a href="https://theconversation.com/back-to-the-moon-a-space-lawyer-and-planetary-scientist-on-what-it-will-take-to-share-the-benefits-of-new-lunar-exploration-podcast-202415">potential uses</a> are incredibly far off – from <a href="https://theconversation.com/mining-the-moon-110744">mining the Moon for resources</a> to sending out <a href="https://www.airandspaceforces.com/raymond-foresees-cislunar-space-as-key-terrain-guardians-going-to-space/">military satellites</a> to orbit around the Moon – missions to the Moon in the near term will help inform scientists and stakeholders of future possibilities. </p>
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<a href="https://theconversation.com/returning-to-the-moon-can-benefit-commercial-military-and-political-sectors-a-space-policy-expert-explains-209300">Returning to the Moon can benefit commercial, military and political sectors – a space policy expert explains</a>
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<h2>2. Searching for sulfur</h2>
<p><a href="https://theconversation.com/indias-chandrayaan-3-landed-on-the-south-pole-of-the-moon-a-space-policy-expert-explains-what-this-means-for-india-and-the-global-race-to-the-moon-212171">India’s Chandrayaan-3 lander touched down</a> on the Moon’s surface, just a few miles away from the lunar south pole, in late August 2023. </p>
<p><a href="https://robotsguide.com/robots/pragyan">Its rover, called Pragyan</a>, took measurements of the lunar surface and found the <a href="https://www.lpi.usra.edu/publications/books/lunar_sourcebook/pdf/Chapter07.pdf">soil near the south pole</a> contains <a href="https://www.isro.gov.in/LIBSResults.html">a surprise – sulfur</a>. </p>
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<iframe width="440" height="260" src="https://www.youtube.com/embed/rrTtLze5Ydk?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">India’s lunar rover Pragyan rolls out of the lander and onto the surface.</span></figcaption>
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<p>As <a href="https://scholar.google.com/citations?user=wKuEBj0AAAAJ&hl=en">Jeffrey Gillis-Davis</a>, a <a href="https://theconversation.com/chandrayaan-3s-measurements-of-sulfur-open-the-doors-for-lunar-science-and-exploration-212950">physicist at Washington University in St. Louis, wrote</a>, future Moon missions or a <a href="https://www.nasa.gov/feature/goddard/2021/nasa-s-artemis-base-camp-on-the-moon-will-need-light-water-elevation">future Moon base</a> could use lunar sulfur as an ingredient in everything from <a href="https://ntrs.nasa.gov/api/citations/19980001900/downloads/19980001900.pdf">fuel and fertilizer to concrete</a>.</p>
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<a href="https://theconversation.com/chandrayaan-3s-measurements-of-sulfur-open-the-doors-for-lunar-science-and-exploration-212950">Chandrayaan-3's measurements of sulfur open the doors for lunar science and exploration</a>
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<h2>3. Water in ice</h2>
<p>But <a href="https://theconversation.com/scientists-suspect-theres-ice-hiding-on-the-moon-and-a-host-of-missions-from-the-us-and-beyond-are-searching-for-it-216060">sulfur’s not the only resource</a> the lunar south pole could have to offer. For several years, scientists have predicted that the lunar south pole <a href="https://nssdc.gsfc.nasa.gov/planetary/ice/ice_moon.html">might have water</a> in the form of ice. And Chandrayaan-3’s <a href="https://theconversation.com/chandrayaan-3s-measurements-of-sulfur-open-the-doors-for-lunar-science-and-exploration-212950">sulfur discovery</a> gives scientists more insight into how and how recently ice might have formed on the surface.</p>
<p>Comets or <a href="https://doi.org/10.3847/PSJ/ac649c">volcanic activity</a> <a href="https://doi.org/10.1016/j.chemer.2021.125858">could have brought water</a> to the Moon years ago. If volcanic activity is the culprit for water’s appearance, scientists would also expect to see sulfur in higher levels, <a href="https://scholar.google.com/citations?user=kgXwvksAAAAJ&hl=en">wrote Paul Hayne</a>, an assistant professor of astrophysical and planetary sciences at the University of Colorado Boulder.</p>
<p>A host of future missions to the Moon, including <a href="https://science.nasa.gov/mission/viper/in-depth/">NASA’s VIPER mission</a> planned for 2024, will continue to investigate where ice could be hiding on the Moon. </p>
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Read more:
<a href="https://theconversation.com/scientists-suspect-theres-ice-hiding-on-the-moon-and-a-host-of-missions-from-the-us-and-beyond-are-searching-for-it-216060">Scientists suspect there's ice hiding on the Moon, and a host of missions from the US and beyond are searching for it</a>
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<h2>4. Moon debris</h2>
<p>With all the Moon missions, <a href="https://www.jhuapl.edu/NewsStory/221205-apl-cislunar-traffic-management">both current and upcoming</a>, some experts have raised concerns about the <a href="https://theconversation.com/if-a-satellite-falls-on-your-house-space-law-protects-you-but-there-are-no-legal-penalties-for-leaving-junk-in-orbit-160757">increased space junk</a> in the “<a href="https://www.afrl.af.mil/Portals/90/Documents/RV/A%20Primer%20on%20Cislunar%20Space_Dist%20A_PA2021-1271.pdf?ver=vs6e0sE4PuJ51QC-15DEfg%3D%3D">cislunar space</a>” – or the space between Earth and the Moon and around the Moon. </p>
<p>NASA doesn’t currently track the space junk left behind from its missions, and <a href="https://theconversation.com/space-junk-in-earth-orbit-and-on-the-moon-will-increase-with-future-missions-but-nobodys-in-charge-of-cleaning-it-up-212421">this lack of oversight</a> has many people worried. </p>
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<a href="https://images.theconversation.com/files/508150/original/file-20230203-7549-e3xoli.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A large, black telescope." src="https://images.theconversation.com/files/508150/original/file-20230203-7549-e3xoli.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/508150/original/file-20230203-7549-e3xoli.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=794&fit=crop&dpr=1 600w, https://images.theconversation.com/files/508150/original/file-20230203-7549-e3xoli.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=794&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/508150/original/file-20230203-7549-e3xoli.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=794&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/508150/original/file-20230203-7549-e3xoli.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=997&fit=crop&dpr=1 754w, https://images.theconversation.com/files/508150/original/file-20230203-7549-e3xoli.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=997&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/508150/original/file-20230203-7549-e3xoli.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=997&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
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<span class="caption">A team of students and professors at the University of Arizona built a telescope to track objects near the Moon.</span>
<span class="attribution"><span class="source">Vishnu Reddy/University of Arizona</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
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<p>One team at the University of Arizona has started <a href="https://news.arizona.edu/story/75m-effort-seeks-prevent-lunar-traffic-jams">building a catalog of debris</a> left in this space. Team members started off by identifying a few large objects, and as their methods got better, they <a href="https://theconversation.com/more-lunar-missions-means-more-space-junk-around-the-moon-two-scientists-are-building-a-catalog-to-track-the-trash-196645">were able to see objects</a> as small as a cereal box. The team hopes this work will one day improve the sustainability of future lunar missions. </p>
<p>“While there is still a long way to go, these efforts are designed to ultimately form the basis for a catalog that will help lead to safer, more sustainable use of cislunar orbital space as humanity begins its expansion off of the Earth,” <a href="https://scholar.google.com/citations?user=XCYhJqcAAAAJ&hl=en">writes Vishnu Reddy</a>, a professor of planetary science at the University of Arizona. </p>
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<a href="https://theconversation.com/more-lunar-missions-means-more-space-junk-around-the-moon-two-scientists-are-building-a-catalog-to-track-the-trash-196645">More lunar missions means more space junk around the Moon – two scientists are building a catalog to track the trash</a>
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<h2>5. Future flyers</h2>
<p>Early this year, <a href="https://spacenews.com/nasa-announces-crew-for-artemis-2-mission/">NASA announced</a> who will make up the crew of their <a href="https://www.nasa.gov/mission/artemis-ii/">Artemis II mission</a>. Set for late 2024, Artemis II will fly by the Moon and test the technology and equipment planned for use in future missions. It will also mark the <a href="https://theconversation.com/meet-the-next-four-people-headed-to-the-moon-how-the-diverse-crew-of-artemis-ii-shows-nasas-plan-for-the-future-of-space-exploration-203214">first time people are close to the lunar surface</a> in over 50 years. </p>
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<span class="caption">Crew members of the Artemis II mission are NASA astronauts Christina Hammock Koch, Reid Wiseman and Victor Glover and Canadian Space Agency astronaut Jeremy Hansen.</span>
<span class="attribution"><a class="source" href="https://www.nasa.gov/press-release/nasa-names-astronauts-to-next-moon-mission-first-crew-under-artemis">NASA</a></span>
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<p>Three of the four crew members <a href="https://theconversation.com/meet-the-next-four-people-headed-to-the-moon-how-the-diverse-crew-of-artemis-ii-shows-nasas-plan-for-the-future-of-space-exploration-203214">have spent time in space</a>, with the fourth having spent lots of time in spaceflight simulations. Each started their careers as a military pilot, just like all the astronauts of the Apollo missions. But this crew represents more racial and gender diversity than the astronauts of the Apollo era. </p>
<p>“Unlike the Apollo program of the 1960s and 1970s, with Artemis, NASA has placed a heavy emphasis on building a <a href="https://www.nytimes.com/2022/11/16/science/nasa-launch-artemis-1.html">politically sustainable lunar program</a> by fostering the participation of a diverse group of people and countries,” <a href="https://scholar.google.com/citations?user=PxIOz7cAAAAJ&hl=en">wrote Wendy Whitman Cobb</a>, a professor of strategy and security studies at Air University.</p>
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Read more:
<a href="https://theconversation.com/meet-the-next-four-people-headed-to-the-moon-how-the-diverse-crew-of-artemis-ii-shows-nasas-plan-for-the-future-of-space-exploration-203214">Meet the next four people headed to the Moon – how the diverse crew of Artemis II shows NASA's plan for the future of space exploration</a>
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<p><em>This story is a roundup of articles from The Conversation’s archives.</em></p><img src="https://counter.theconversation.com/content/216808/count.gif" alt="The Conversation" width="1" height="1" />
Chandrayaan-3’s successful landing on the Moon made 2023 a big year for lunar exploration, and future years will come with even more discoveries.Mary Magnuson, Assistant Science EditorLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2159792023-11-07T18:42:34Z2023-11-07T18:42:34ZOver the past six years, governments proposed launching over one million satellites, but where will they all go?<figure><img src="https://images.theconversation.com/files/557828/original/file-20231106-270141-rjcguo.jpg?ixlib=rb-1.1.0&rect=0%2C0%2C3840%2C2155&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">As the number of satellites in orbit increase, so will the possibilities of space debris. There are currently 8,000 satellites in orbit, but hundreds of thousands more are being proposed.</span> <span class="attribution"><span class="source">(Shutterstock)</span></span></figcaption></figure><iframe style="width: 100%; height: 100px; border: none; position: relative; z-index: 1;" allowtransparency="" allow="clipboard-read; clipboard-write" src="https://narrations.ad-auris.com/widget/the-conversation-canada/over-the-past-six-years-governments-proposed-launching-over-one-million-satellites-but-where-will-they-all-go" width="100%" height="400"></iframe>
<p>In September 2021, Rwanda announced that it was <a href="https://spacenews.com/satellite-operators-criticize-extreme-megaconstellation-filings/">planning to launch over 300,000 satellites</a>. Three months later, a Canadian company, having previously launched two dozen <a href="https://www.asc-csa.gc.ca/eng/satellites/cubesat/what-is-a-cubesat.asp">CubeSats</a>, <a href="https://spacenews.com/kepler-plots-relay-network-to-serve-thousands-of-satellite-terminals/">said it would launch an additional 100,000</a>. Then, <a href="https://www.spaceintelreport.com/e-space-registers-116640-satellite-c-band-network-with-itu-through-france-300000-satellite-rwanda-network-is-no-more/">a French company did likewise</a>. And SpaceX, which has already launched <a href="https://planet4589.org/space/con/star/stats.html">around 5,000 satellites</a>, <a href="https://advanced-television.com/2023/10/12/spacex-applies-for-29988-new-satellites/">now has plans for over 60,000 more</a>. </p>
<p>There are currently only about <a href="https://www.ucsusa.org/resources/satellite-database">8,000 active satellites in orbit</a>. What’s going on?</p>
<p>Before a satellite is launched, a nation state must file its proposed satellite system with the <a href="https://www.itu.int/en/Pages/default.aspx">International Telecommunication Union</a> (ITU) to coordinate radiofrequency spectrum on behalf of the satellite operator, which could be a company, university or government agency. </p>
<p>These filings are made years ahead of the satellite launch, so the ITU can oversee coordination between different satellite operators and ensure that new satellite signals don’t drown existing ones out.</p>
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<span class="caption">The UN International Telecommunication Union offices in Geneva, Switzerland.</span>
<span class="attribution"><span class="source">(Shutterstock)</span></span>
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<h2>One million filings</h2>
<p><a href="https://doi.org/10.1126/science.adi4639">In a new Policy Forum article published in <em>Science</em></a>, we found that, between 2017 and 2022, countries collectively made filings for over one million satellites across more than 300 separate systems of multiple satellites working together, known as constellations.</p>
<p>This creates two intertwined problems. Either many of these satellites will actually be launched, <a href="https://doi.org/10.1016/j.actaastro.2020.01.016">causing an environmental crisis</a> through thousands of rocket launches into <a href="https://doi.org/10.1038/s41598-021-89909-7">increasingly crowded Earth orbits</a>, or operators are filing for more satellites than they intend to launch, perhaps with a view to hedging their bets, getting investor attention or selling the portions of radio spectrum for profit. </p>
<p>A closer look shows that the latter option is more likely.</p>
<h2>Congested orbits</h2>
<p>If even 10 per cent of the filed-for satellites launch, low Earth orbit would become congested with over 100,000 additional satellites. Collisions between satellites would generate space debris, which would in turn cause further collisions. </p>
<p>Reentering satellites would burn up in the atmosphere, <a href="https://phys.org/news/2023-10-signatures-space-age-spacecraft-metals.amp">potentially affecting the climate</a>, while surviving pieces of debris might strike people or aircraft. We already face these risks today, but they would increase by an order of magnitude.</p>
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Read more:
<a href="https://theconversation.com/airplanes-face-a-growing-risk-of-being-hit-by-uncontrolled-re-entries-of-rockets-used-to-launch-satellites-202400">Airplanes face a growing risk of being hit by uncontrolled re-entries of rockets used to launch satellites</a>
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<hr>
<p>The problem may be more mundane, meaning that satellite operators are fiddling the numbers. Take E-Space, the French company. It is behind <a href="https://spacenews.com/wyler-raises-50-million-for-sustainable-megaconstellation/">both the 337,320-satellite constellation</a> filed through Rwanda in 2021, and a <a href="https://www.spaceintelreport.com/e-space-registers-116640-satellite-c-band-network-with-itu-through-france-300000-satellite-rwanda-network-is-no-more/">116,640-satellite constellation filed through France in 2023</a>. </p>
<p>Despite these ambitious filings, the company’s CEO, Greg Wyler, said it is planning for “<a href="https://youtu.be/1op-XeUUWMY?si=kKrb7TETXElsqwTV&t=491">at least 30,000 satellites</a>,” while its director of product development mentioned “<a href="https://www.spaceintelreport.com/e-space-registers-116640-satellite-c-band-network-with-itu-through-france-300000-satellite-rwanda-network-is-no-more/">just a few thousand satellites</a>.” Are any of these numbers real? </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/557889/original/file-20231106-19-ni6o94.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="photo of a night sky with blurred dots of light" src="https://images.theconversation.com/files/557889/original/file-20231106-19-ni6o94.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/557889/original/file-20231106-19-ni6o94.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/557889/original/file-20231106-19-ni6o94.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/557889/original/file-20231106-19-ni6o94.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/557889/original/file-20231106-19-ni6o94.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/557889/original/file-20231106-19-ni6o94.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/557889/original/file-20231106-19-ni6o94.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Starlink satellites passing over New Mexico.</span>
<span class="attribution"><a class="source" href="https://noirlab.edu/public/images/noirlab2206b/">(NOIRLab/M. Lewinsky)</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
</figcaption>
</figure>
<h2>Countries of convenience</h2>
<p>There are more signs that companies are attempting to game the ITU system. </p>
<p>OneWeb, which has 634 satellites in orbit, has made filings for 6,118 more satellites through three countries: <a href="https://www.science.org/doi/10.1126/science.adi4639">Mexico, France and the United Kingdom</a>. </p>
<p>SpaceX has made filings through the <a href="https://www.science.org/doi/10.1126/science.adi4639">United States, Norway, Germany</a> and <a href="https://www.spaceintelreport.com/spacex-files-29988-satellite-w-band-network-using-kingdom-of-tonga-as-regulatory-home/">now Tonga</a>. It is unclear why this is happening, but all these states have different administrative rules — <a href="https://www.ofcom.org.uk/__data/assets/pdf_file/0028/256564/notice-of-satellite-filing-charges-2023-24.pdf">and fees</a> — associated with satellite filings. </p>
<p>In the global shipping industry, flag-of-convenience governments register ships for companies that seek lower operating costs through looser regulations and lax enforcement. Over <a href="https://unctadstat.unctad.org/CountryProfile/MaritimeProfile/en-GB/004/index.html">44 per cent of the world’s ships by tonnage</a> are registered in just three countries: Panama, Liberia and the Marshall Islands. These ships historically <a href="https://doi.org/10.1016/j.marpol.2018.10.026">have worse safety records and poorer labour conditions</a>. </p>
<p>Tonga, now home to <a href="https://www.spaceintelreport.com/spacex-files-29988-satellite-w-band-network-using-kingdom-of-tonga-as-regulatory-home/">SpaceX’s October 2023 filing for 29,998 satellites</a>, has filed for satellites before. In the 1980s, it <a href="https://www.nytimes.com/1990/08/28/business/tiny-tonga-seeks-satellite-empire-in-space.html">filed for 16 satellite slots</a>, eventually gaining nine slots which it promptly leased to foreign operators. </p>
<p>Other satellite operators weren’t happy; one even <a href="http://ojs-dev.byuh.edu/index.php/pacific/article/view/345/327">moved a satellite into one of Tonga’s slots in protest</a>. Yet Tonga made millions of dollars through the leases.</p>
<h2>Updating the rules</h2>
<p>The recent megaconstellation filings are of unprecedented size, raising multiple challenges. The ITU aims to prevent interference between satellites by modelling their signal power output, and the proliferation of satellites and the splitting of filings between different states are making that difficult. </p>
<p>The ITU — which is a United Nations agency that predates the UN, making it the oldest agency in the organization — has well-established processes for updating its rules. The 193 member states meet every three to four years at <a href="https://www.itu.int/en/ITU-R/conferences/wrc/Pages/default.aspx">World Radiocommunication Conferences</a>, where new rules are debated and adopted. </p>
<p>In 2019, member states agreed to <a href="https://www.itu.int/dms_pub/itu-r/opb/act/R-ACT-WRC.14-2019-PDF-E.pdf">create “milestones” for the deployment of satellite constellations</a>: launch 10 per cent of satellites within two years of the first launch, 50 per cent within five years and the whole constellation within seven years. However, the first satellite can be launched up to seven years after the filing, giving companies considerable time and flexibility.</p>
<p>The ITU should consider speeding up this process. It could also introduce fees that disincentivise large or speculative filings. </p>
<h2>Environmental responsibility</h2>
<p>The Secretary General of the ITU, Doreen Bogdan-Martin, has said <a href="https://spacenews.com/itu-emphasizes-importance-of-space-sustainability/">the ITU is increasingly prioritizing space sustainability</a>. But it must balance that goal with its mandate, which focuses on radio spectrum management.</p>
<p><div data-react-class="InstagramEmbed" data-react-props="{"url":"https://www.instagram.com/p/CoFQscRtjec","accessToken":"127105130696839|b4b75090c9688d81dfd245afe6052f20"}"></div></p>
<p>From Nov. 20 to Dec. 15, 2023, the ITU member states will <a href="https://www.itu.int/wrc-23/">convene in Dubai</a> for this year’s World Radiocommunication Conference. But don’t expect radical changes this year; any proposals introduced now are unlikely to be finalised before the next conference in 2027. </p>
<p>And who knows what SpaceX, E-Space and other companies will get up to before then?</p><img src="https://counter.theconversation.com/content/215979/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>The authors do not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and have disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Countries have submitted applications for hundreds of thousands of new satellites to be launched. The scale poses challenges for overcrowding orbit, with environmental and safety challenges.Ewan Wright, PhD candidate, Interdisciplinary Studies, University of British ColumbiaAndrew Falle, Research Coordinator and Junior Fellow, Outer Space Institute, University of British ColumbiaLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2155452023-10-20T02:10:01Z2023-10-20T02:10:01ZSpace is getting crowded with satellites and space junk. How do we avoid collisions?<figure><img src="https://images.theconversation.com/files/554716/original/file-20231019-15-if092m.jpg?ixlib=rb-1.1.0&rect=882%2C1499%2C4543%2C3237&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="https://orbitaldebris.jsc.nasa.gov/photo-gallery/">NASA ODPO</a></span></figcaption></figure><p>Reports this week suggest <a>a near-collision</a> between an Australian satellite and a suspected Chinese military satellite.</p>
<p>Meanwhile, earlier this month, the US government issued the first ever space junk fine. The Federal Communications Commission <a href="https://www.fcc.gov/document/fcc-takes-first-space-debris-enforcement-action">handed a US$150,000 penalty</a> to the DISH Network, a publicly traded company providing satellite TV services. </p>
<p>It came as a surprise to many in the space industry, as the fine didn’t relate to any recent debris – it was issued for a communications satellite that has been in space for more than 21 years. It was <a href="https://nssdc.gsfc.nasa.gov/nmc/spacecraft/display.action?id=2002-006A">EchoStar-7</a>, which failed to meet the orbit requirements outlined in a previously agreed debris mitigation plan.</p>
<p>The EchoStar-7 fine might be a US first, but it probably won’t be the last. We are entering an unprecedented era of space use and can expect the number of active <a href="https://time.com/6262389/space-junk-increasing-problem/#:%7E:text=The%20researchers%20report%20that%20there,launching%20all%20of%20that%20hardware.">satellites in space</a> to increase by 700% by the end of the decade.</p>
<p>As our local space gets more crowded, keeping an eye on tens of thousands of satellites and bits of space junk will only become more important. So researchers have a new field for this: space domain awareness.</p>
<h2>Three types of orbit, plus junk</h2>
<p>Humans have been launching satellites into space since 1957 and in the past 66 years have become rather good at it. There are currently <a href="https://orbit.ing-now.com">more than 8,700 active satellites</a> in various orbits around Earth.</p>
<p>Satellites tend to be in three main orbits, and understanding these is key to understanding the complex nature of space debris.</p>
<figure class="align-center ">
<img alt="An image of Earth with circles around it to indicate the distance of standard satellite orbits" src="https://images.theconversation.com/files/554715/original/file-20231019-29-mqpggf.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/554715/original/file-20231019-29-mqpggf.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=368&fit=crop&dpr=1 600w, https://images.theconversation.com/files/554715/original/file-20231019-29-mqpggf.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=368&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/554715/original/file-20231019-29-mqpggf.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=368&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/554715/original/file-20231019-29-mqpggf.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=462&fit=crop&dpr=1 754w, https://images.theconversation.com/files/554715/original/file-20231019-29-mqpggf.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=462&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/554715/original/file-20231019-29-mqpggf.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=462&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Types of orbits around Earth classified by altitude (not to scale).</span>
<span class="attribution"><span class="source">Pexels/The Conversation</span>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span>
</figcaption>
</figure>
<p>The most common orbit for satellites is <a href="https://www.esa.int/ESA_Multimedia/Images/2020/03/Low_Earth_orbit">low Earth orbit</a>, with at least <a href="https://www.ucsusa.org/resources/satellite-database">5,900 active satellites</a>. Objects in low Earth orbit tend to reside up to 1,000km above Earth’s surface and are constantly on the move. The International Space Station is an example of a low Earth orbit object, travelling around Earth 16 times every day. </p>
<p>Higher up is the <a href="https://www.esa.int/Applications/Connectivity_and_Secure_Communications/Orbits">medium Earth orbit</a>, where satellites sit between 10,000 and 20,000km above Earth. It’s not a particularly busy place, but is home to some of the most important satellites ever launched – they provide us with the <a href="https://www.gps.gov/">global positioning system</a> or GPS.</p>
<p>Finally, we have very high altitude satellites in <a href="https://www.esa.int/Enabling_Support/Space_Transportation/Types_of_orbits#GEO">geosynchronous orbit</a>. In this orbit, satellites are upwards of 35,000km above Earth, in orbits that match the rate of Earth’s rotation. One special type of this orbit is a geostationary Earth orbit. It lies on the same plane as Earth’s equator, making the satellites appear stationary from the ground.</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/6zoQmV3PGNc?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">Visualisation of The European Space Agency’s Space Debris Office statistics on space debris orbiting Earth (as of January 8 2021).</span></figcaption>
</figure>
<p>As you can tell, Earth’s surrounds are buzzing with satellite activity. It only gets more chaotic when we factor in <a href="https://www.nhm.ac.uk/discover/what-is-space-junk-and-why-is-it-a-problem.html">space junk</a>, defined as disused artificial debris in orbit around Earth.</p>
<p>Space junk can range from entire satellites that are no longer in use or working, down to millimetre-wide bits of spacecraft and launch vehicles left in orbit. <a href="https://www.esa.int/Space_Safety/Space_Debris/Space_debris_by_the_numbers">Latest estimates</a> suggest there are more than 130 million pieces of space debris, with only 35,000 of those large enough (greater than 10cm) to be routinely tracked from the ground. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/space-junk-in-earth-orbit-and-on-the-moon-will-increase-with-future-missions-but-nobodys-in-charge-of-cleaning-it-up-212421">Space junk in Earth orbit and on the Moon will increase with future missions − but nobody's in charge of cleaning it up</a>
</strong>
</em>
</p>
<hr>
<h2>How do we track them all?</h2>
<p>This is where space domain awareness comes in. It is the field of detecting, tracking and monitoring objects in Earth’s orbit, including active satellites and space debris.</p>
<p>We do much of this with ground-based tracking, either through radar or optical systems like telescopes. While radar can easily track objects in low Earth orbit, higher up we need optical sensors. Objects in medium Earth orbit and geostationary orbit can be tracked using sunlight reflected towards Earth.</p>
<p>For reliable and continuous space domain awareness, we need multiple sensors contributing to this around the globe.</p>
<p>Below you can see what high-altitude satellites can look like to telescopes on Earth, appearing to stay still as the stars move by. </p>
<figure>
<iframe src="https://player.vimeo.com/video/848579076" width="500" height="281" frameborder="0" webkitallowfullscreen="" mozallowfullscreen="" allowfullscreen=""></iframe>
<figcaption><span class="caption">Tracking two Optus satellites 16km apart, using EOS’ 0.7m deep space telescope at Learmonth, Western Australia. Source: EOS - Electro Optic Systems.</span></figcaption>
</figure>
<h2>Australia’s role in space awareness</h2>
<p>Thanks to our position on Earth, Australia has a unique opportunity to contribute to space domain awareness. The US already houses several facilities on the west coast of Australia as part of the <a href="https://nsarchive.gwu.edu/briefing-book/intelligence/2023-03-13/whats-there-where-it-and-whats-it-doing-us-space-surveillance">Space Surveillance Network</a>. That’s because on the west coast, telescopes can work in dark night skies with minimal light pollution from large cities.</p>
<p>Furthermore, we are currently working on a <a href="https://www.cgi.com/au/en-au/news/space/cgi-rmit-and-swinburne-university-technology-enhance-australian-space-domain-awareness">space domain awareness technology demonstrator</a> (a proof of concept), funded by <a href="https://smartsatcrc.com">SmartSat CRC</a>. This is a government-funded consortium of universities and other research organisations, along with industry partners such as the IT firm CGI.</p>
<p>We are combining our expertise in observational astrophysics, advanced data visualisation, artificial intelligence and space weather. Our goal is to have technology that understands what is happening in space minute-by-minute. Then, we can line up follow-up observations and monitor the objects in orbit. Our team is currently working on geosynchronous orbit objects, which includes active and inactive satellites. </p>
<p>EchoStar-7 was just one example of the fate of a retired spacecraft – the FCC is sending a strong warning to all other companies to ensure their debris mitigation plans are met.</p>
<p>Inactive objects in orbit could pose a collision risk to each other, leading to a rapid increase in space debris. If we want to use Earth’s space domain for as long as possible, we need to keep it safe for all.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/harpoons-robots-and-lasers-how-to-capture-defunct-satellites-and-other-space-junk-and-bring-it-back-to-earth-189698">Harpoons, robots and lasers: how to capture defunct satellites and other space junk and bring it back to Earth</a>
</strong>
</em>
</p>
<hr>
<p><em>Acknowledgment: The authors would like to thank Sholto Forbes-Spyratos, military space lead at CGI Space, Defence and Intelligence Australia, for his contribution to this article.</em></p><img src="https://counter.theconversation.com/content/215545/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Sara Webb receives funding through a research project co-funded by CGI technologies and SmartSat CRC, on work related to space domain awareness. She is a member of the Astronomical Society of Australia and American Society for Gravitational and Space Research. </span></em></p><p class="fine-print"><em><span>Brett Carter is an Editor of the American Geophysical Union journal Space Weather. He receives funding from the Australian Research Council, SmartSat CRC and FrontierSI. He is also a member of the Australian Institute of Physics and the American Geophysical Union.</span></em></p><p class="fine-print"><em><span>Christopher Fluke works for Swinburne University of Technology. He receives funding from the SmartSat CRC, including funding to support a research collaboration with CGI and RMIT. He is a member of the Astronomical Society of Australia and the International Astronomical Union.</span></em></p>Earth’s orbits are getting more and more crowded. To keep track of everything and avoid collisions and catastrophes, we need a new field: space domain awareness.Sara Webb, Postdoctoral Research Fellow, Centre for Astrophysics and Supercomputing, Swinburne University of TechnologyBrett Carter, Associate Professor, RMIT UniversityChristopher Fluke, SmartSat Professorial Chair, Swinburne University of TechnologyLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2124212023-08-31T12:23:19Z2023-08-31T12:23:19ZSpace junk in Earth orbit and on the Moon will increase with future missions − but nobody’s in charge of cleaning it up<figure><img src="https://images.theconversation.com/files/545374/original/file-20230829-25-ksnt5w.jpg?ixlib=rb-1.1.0&rect=0%2C0%2C4500%2C2627&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">An artist's rendering of debris floating through Earth's orbit. </span> <span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/garbage-royalty-free-image/474381690?phrase=space+junk&adppopup=true">Petrovich9/iStock via Getty Images</a></span></figcaption></figure><p>There’s a lot of trash on the Moon right now – including nearly <a href="https://www.vox.com/science-and-health/2019/3/22/18236125/apollo-moon-poop-mars-science">100 bags of human waste</a> – and with countries around the globe traveling <a href="https://theconversation.com/returning-to-the-moon-can-benefit-commercial-military-and-political-sectors-a-space-policy-expert-explains-209300">to the Moon</a>, there’s going to be a lot more, both on the lunar surface and in Earth’s orbit.</p>
<p>In August 2023, Russia’s <a href="https://theconversation.com/russia-has-declared-a-new-space-race-hoping-to-join-forces-with-china-heres-why-thats-unlikely-211993">Luna-25</a> probe crashed into the Moon’s surface, while India’s <a href="https://theconversation.com/indias-chandrayaan-3-landed-on-the-south-pole-of-the-moon-a-space-policy-expert-explains-what-this-means-for-india-and-the-global-race-to-the-moon-212171">Chandrayann-3</a> mission successfully landed in the southern polar region, making India the fourth country to land on the Moon.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/545376/original/file-20230829-16-rsr2b4.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A group of cheering, smiling people hold signs depicting the Chandrayaan-3 lander." src="https://images.theconversation.com/files/545376/original/file-20230829-16-rsr2b4.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/545376/original/file-20230829-16-rsr2b4.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=411&fit=crop&dpr=1 600w, https://images.theconversation.com/files/545376/original/file-20230829-16-rsr2b4.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=411&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/545376/original/file-20230829-16-rsr2b4.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=411&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/545376/original/file-20230829-16-rsr2b4.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=516&fit=crop&dpr=1 754w, https://images.theconversation.com/files/545376/original/file-20230829-16-rsr2b4.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=516&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/545376/original/file-20230829-16-rsr2b4.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=516&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">India’s Chandrayaan-3 lander successfully touched down on the south pole of the Moon, sparking celebrations across the country.</span>
<span class="attribution"><a class="source" href="https://newsroom.ap.org/detail/IndiaLunarMission/ac52e7da7b46474a91706ffa43f7c99a/photo?Query=india%20moon%20landing&mediaType=photo&sortBy=&dateRange=Anytime&totalCount=89&currentItemNo=24">AP Photo/Rajanish Kakade</a></span>
</figcaption>
</figure>
<p>With more countries landing on the Moon, people back on Earth will have to think about what happens to all the landers, waste and miscellaneous debris left on the lunar surface and in orbit.</p>
<p>I’m a professor of astronomy who has written a book about the <a href="https://wwnorton.com/books/Beyond/">future of space travel</a>, articles about <a href="https://zenodo.org/record/1477986">our future off-Earth</a>, <a href="https://thehill.com/opinion/international/575903-is-conflict-in-space-inevitable">conflict in space</a>, <a href="https://thehill.com/opinion/national-security/3263430-space-an-increasingly-contested-and-congested-frontier/">space congestion</a> and the <a href="https://doi.org/10.2478/sh-2021-0020">ethics of space exploration</a>. Like many other space experts, I’m concerned about the lack of governance around space debris.</p>
<h2>Space is getting crowded</h2>
<p>People think of space as vast and empty, but the near-Earth environment is starting to get crowded. As many as <a href="https://thenationaldigest.com/up-to-100-space-missions-to-the-moon-to-take-place-in-the-next-decade/">100 lunar missions</a> are planned over the next decade by governments and private companies like SpaceX and Blue Origin. </p>
<p>Near-Earth orbit is even more congested than the space between Earth and the Moon. It’s from 100 to 500 miles straight up, compared with 240,000 miles to the Moon. Currently there are nearly <a href="https://orbit.ing-now.com/low-earth-orbit/">7,700 satellites</a> within a few hundred miles of the Earth. <a href="https://theconversation.com/how-many-satellites-are-orbiting-earth-166715">That number</a> could grow to <a href="https://doi.org/10.1063/PT.3.4979">several hundred thousand</a> by 2027. Many of these satellites will be used to deliver internet to developing countries or to <a href="https://theconversation.com/landsat-turns-50-how-satellites-revolutionized-the-way-we-see-and-protect-the-natural-world-186986">monitor agriculture</a> and <a href="https://theconversation.com/how-to-use-free-satellite-data-to-monitor-natural-disasters-and-environmental-changes-198140">climate</a> on Earth. Companies like SpaceX have dramatically <a href="https://theconversation.com/how-spacex-lowered-costs-and-reduced-barriers-to-space-112586">lowered launch costs</a>, driving this wave of activity.</p>
<p>“It’s going to be like an interstate highway, at rush hour in a snowstorm, with everyone driving much too fast,” space launch expert <a href="https://scholar.google.com/citations?user=OEsqBIsAAAAJ&hl=en">Johnathan McDowell</a> <a href="https://www.space.com/how-many-satellites-fit-safely-earth-orbit">told Space.com</a>. </p>
<h2>The problem of space junk</h2>
<p>All this activity creates hazards and debris. Humans have left a lot of junk on the Moon, including spacecraft remains like rocket boosters from over <a href="https://doi.org/10.1038/d41586-022-00542-4">50 crashed landings</a>, nearly <a href="https://www.vox.com/science-and-health/2019/3/22/18236125/apollo-moon-poop-mars-science">100 bags of human waste</a> and miscellaneous objects like a feather, golf balls and boots. It adds up to around <a href="https://www.theatlantic.com/technology/archive/2012/12/the-trash-weve-left-on-the-moon/266465/">200 tons of our trash</a>. </p>
<p>Since <a href="https://theconversation.com/who-owns-the-moon-a-space-lawyer-answers-99974">no one owns the Moon</a>, no one is responsible for <a href="https://www.vox.com/science/2023/8/24/23844280/india-moon-landing-russia-crash-lunar-south-pole-science-consequences-junk">keeping it clean and tidy</a>. </p>
<p>The <a href="https://www.space.com/space-junk-growing-problem-complicated-solution">clutter in Earth’s orbit</a> includes defunct spacecraft, spent rocket boosters and items discarded by astronauts such as a glove, a wrench and a toothbrush. It also includes <a href="https://www.nasa.gov/mission_pages/station/news/orbital_debris.html">tiny pieces of debris</a> like paint flecks. </p>
<p>There are around 23,000 <a href="https://www.nasa.gov/mission_pages/station/news/orbital_debris.html">objects</a> larger than 10 cm (4 inches) and about 100 million pieces of debris larger than 1 mm (0.04 inches). Tiny pieces of junk might not seem like a big issue, but that debris is moving at 15,000 mph (24,140 kph), 10 times faster than a bullet. <a href="https://www.space.com/tiny-space-junk-damage">At that speed</a>, even a fleck of paint can puncture a spacesuit or destroy a sensitive piece of electronics.</p>
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<figcaption><span class="caption">The amount of debris in orbit has increased dramatically since the 1960s.</span></figcaption>
</figure>
<p>In 1978, NASA scientist <a href="https://www.britannica.com/biography/Donald-Kessler">Donald Kessler</a> described a scenario where collisions between orbiting pieces of debris create more debris, and the amount of debris grows exponentially, potentially rendering near-Earth orbit unusable. Experts call this the “<a href="https://www.techtarget.com/whatis/definition/Kessler-Syndrome">Kessler syndrome</a>.” </p>
<h2>Nobody is in charge up there</h2>
<p>The United Nations <a href="https://www.unoosa.org/oosa/en/ourwork/spacelaw/treaties/introouterspacetreaty.html">Outer Space Treaty of 1967</a> says that no country can “own” the Moon or any part of it, and that celestial bodies should only be used for peaceful purposes. But the treaty is mute about companies and individuals, and it says nothing about how space resources can and can’t be used. </p>
<p>The United Nations <a href="https://www.unoosa.org/oosa/en/ourwork/spacelaw/treaties/intromoon-agreement.html">Moon Agreement of 1979</a> held that the Moon and its natural resources are the common heritage of humanity. However, the United States, Russia and China never signed it, and in 2016 the <a href="https://www.congress.gov/bill/114th-congress/house-bill/2262/text">U.S. Congress created a law</a> that unleashed the American commercial space industry with very few restrictions. </p>
<p>Because of its lack of regulation, space junk is an example of a “<a href="https://carnegieendowment.org/2021/03/09/space-is-great-commons.-it-s-time-to-treat-it-as-such-pub-84018">tragedy of the commons</a>,” where many interests have access to a common resource, and it may become depleted and unusable to everyone, because no interest can stop another from overexploiting the resource.</p>
<p>Scientists argue that to avoid a tragedy of the commons, the orbital space environment should be seen as a <a href="https://doi.org/10.1038/s41550-022-01655-6">global commons</a> worthy of protection by the <a href="https://hir.harvard.edu/the-uns-role-in-planetary-protection/">United Nations</a>. The lead author of a <a href="https://doi.org/10.1038/s41550-022-01655-6">Nature article</a> arguing for a global commons filed an <a href="https://andyxlastro.me/wp-content/uploads/2021/08/Amicus-Brief-Lawrence.pdf">amicus brief</a> – a type of outside comment offering support or expertise – on a case that went to the <a href="https://docs.fcc.gov/public/attachments/DOC-386646A1.pdf">U.S. Court of Appeals for the District of Columbia Circuit</a> in late 2021.</p>
<p>The author and his research collaborators argued that U.S. environmental regulations should apply to the licensing of space launches. However, the court declined to rule on the environmental issue because it said the group lacked standing.</p>
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<figcaption><span class="caption">The tragedy of the commons asserts that if everyone has unlimited access to a resource, then in the long run it may become depleted and unusable.</span></figcaption>
</figure>
<p>National geopolitical and commercial interests will likely take precedence over interplanetary conservation efforts unless the United Nations acts. A new treaty may emerge from the work of the U.N. <a href="https://www.unoosa.org/">Office for Outer Space Affairs</a>, which in May 2023 generated a <a href="https://indonesia.un.org/sites/default/files/2023-07/our-common-agenda-policy-brief-outer-space-en.pdf">policy document</a> to address the sustainable development of activities in space.</p>
<p>The U.N. can regulate the activities of only its member states, but it has a <a href="https://www.unoosa.org/oosa/en/ourwork/spacelaw/capacitybuilding/advisory-services/index.html">project</a> to help member states craft national-level policies that advance the goals of sustainable development.</p>
<p>NASA has created and signed the <a href="https://www.nasa.gov/specials/artemis-accords/index.html">Artemis Accords</a>, broad but nonbinding principles for cooperating peacefully in space. They have been signed by 28 countries, but the list does not include China or Russia. <a href="https://mashable.com/article/who-owns-moon-resources-nasa-artemis">Private companies</a> are not party to the accords either, and some <a href="https://www.axios.com/2021/07/13/branson-bezos-space-travel-billionaires-nasa">space entrepreneurs</a> have deep pockets and big ambitions.</p>
<p>The lack of regulation and the current gold rush approach to space exploration mean that space junk and waste will continue to accumulate, as will the related problems and dangers.</p><img src="https://counter.theconversation.com/content/212421/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Chris Impey receives funding from the National Science Foundation.</span></em></p>Treaties meant to ensure sustainability in space don’t currently regulate private companies, and not every country has signed on to an agreement for sustainable space exploration.Chris Impey, University Distinguished Professor of Astronomy, University of ArizonaLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2113352023-08-22T01:54:04Z2023-08-22T01:54:04ZSustainability is often an afterthought in space exploration – that needs to change as the industry grows<figure><img src="https://images.theconversation.com/files/543379/original/file-20230818-27-hadks3.jpg?ixlib=rb-1.1.0&rect=317%2C194%2C1648%2C948&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">.</span> <span class="attribution"><a class="source" href="https://www.nasa.gov/image-feature/apollo-8-earthrise">NASA/Bill Anders</a></span></figcaption></figure><p>Aotearoa New Zealand is the latest country to enter the expanding and competitive international space market. </p>
<p>In the <a href="https://www.mbie.govt.nz/science-and-technology/aotearoa-new-zealand-aerospace-strategy/">aerospace strategy</a> and <a href="https://www.mbie.govt.nz/science-and-technology/space/national-space-policy/">national space policy</a>, the government lays out how it intends to grow the domestic space sector by launching rockets and satellites and promoting Earth observation research. </p>
<p>The documents indicate the government’s general priorities in “protecting New Zealand’s national interests” and the “responsible use of space”. </p>
<p>Sustainability is a focus in both strategy and policy but is used interchangeably in three different contexts: </p>
<ul>
<li><p>To “sustain” the economic development of the industry</p></li>
<li><p>to describe the benefits of aerospace technology for sustainability efforts, like monitoring climate change</p></li>
<li><p>to describe the environmental impacts of aerospace activities, largely focused on space debris, while reducing emissions (though the latter is largely a concern for the aviation industry, not space).</p></li>
</ul>
<p>When a part from India’s recent rocket launch <a href="https://www.rnz.co.nz/news/world/494918/australian-space-agency-reveals-origin-of-space-junk-discovered-on-beach-in-western-australia">landed on Australian shores</a> last month, it captured people’s attention – and delivered a reminder that Earth’s orbits are <a href="https://www.space.com/11607-space-junk-rising-orbital-debris-levels-2030.html">teeming</a> with the discards of human endeavours in space. </p>
<p><div data-react-class="Tweet" data-react-props="{"tweetId":"1686134652858482688"}"></div></p>
<p>Space debris indeed poses long-term threats to space activities and Earth’s environment. But sustainability should have a wider focus than the pollution of Earth’s orbital space. </p>
<p>Our new <a href="https://www.sciencedirect.com/science/article/pii/S0094576523003600">research</a> provides key recommendations for expanding our view on the sustainable use of space – and this could reveal unforeseen risks and opportunities for businesses, governments, communities and Indigenous peoples. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/harpoons-robots-and-lasers-how-to-capture-defunct-satellites-and-other-space-junk-and-bring-it-back-to-earth-189698">Harpoons, robots and lasers: how to capture defunct satellites and other space junk and bring it back to Earth</a>
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</em>
</p>
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<h2>What does sustainability in space mean?</h2>
<p>The worsening impacts of <a href="https://royalsociety.org/topics-policy/projects/biodiversity/climate-change-and-biodiversity/">climate change and biodiversity loss</a> have taught us that we cannot easily clean up our messes retrospectively and that pollution has inter-generational consequences. </p>
<p>But factoring in sustainability is usually an afterthought as we continue to compromise environmental, societal and cultural wellbeing for the sake of economic development. The ambiguity in what we mean by sustainability is part of the problem. </p>
<p>Nowhere in New Zealand’s aerospace strategy or policy documents is sustainability actually clarified. What is included, what is excluded, and whose concept of sustainability are we operating with? </p>
<p>Without clarity, it is difficult to develop techniques and targets for sustainability or to be held accountable for missing them. </p>
<h2>Balancing priorities with values</h2>
<p>It is also difficult to draw parallels between different knowledge systems or sectors. But this could help us avoid the mistakes that have led to the current climate and biodiversity crises. </p>
<p>The way economic priorities are balanced with values through a holistic relationship with the Earth, sea and sky is already embedded in many Indigenous cultures around the world, including Māori. </p>
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<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/why-do-different-cultures-see-such-similar-meanings-in-the-constellations-121981">Why do different cultures see such similar meanings in the constellations?</a>
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<p>Aotearoa New Zealand’s founding documents outline the co-existence of two distinct authorities – Māori, represented by hapū (the primary political unit in traditional Māori society at the signing of Te Tiriti o Waitangi) and the British Crown. While the national space policy is committed to recognising and reflecting Māori interests in the space sector, it is not clear how these interests will translate into a genuine partnership approach to decision making. </p>
<p>Our research makes recommendations about how we might consider what we are trying to “sustain”, for whom and over what timeframe, what the requirements are to do so, and who needs to be at the decision-making table.</p>
<h2>Earth, its atmosphere and beyond</h2>
<p>Are we thinking about our future activities just on Earth, or further afield, including planetary exploration and asteroid mining? </p>
<p>Closer to Earth, commercial satellite technology is now a well established method to observe our planet from space. It helps to monitor weather and climate effects and provides crucial telecommunication services. But at what environmental cost to Earth? </p>
<p>There are currently no mandatory regulations for the space industry to report their greenhouse gas emissions or consider the life-cycle impact of their products on Earth’s environment. Without this information, how can we perform any cost-benefit calculations, on Earth or elsewhere? </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/a-rapidly-growing-rocket-industry-could-undo-decades-of-work-to-save-the-ozone-layer-unless-we-act-now-198982">A rapidly growing rocket industry could undo decades of work to save the ozone layer – unless we act now</a>
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</em>
</p>
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<p>We are getting better at sending objects on a <a href="https://theconversation.com/mars-is-littered-with-15-694-pounds-of-human-trash-from-50-years-of-robotic-exploration-188881">one-way trip to Mars</a>, and even to the edge of the solar system. Is space ultimately a dumping ground for waste from human activity?</p>
<h2>Society and culture</h2>
<p>For millennia, the night sky has been a sacred environment, a repository of knowledges and a source of connection for people. It is now threatened by increasing light pollution from mega constellations of satellites and accumulating space debris. </p>
<p>In Australia, <a href="https://theconversation.com/rising-seas-and-a-great-southern-star-aboriginal-oral-traditions-stretch-back-more-than-12-000-years-211114">Aboriginal oral traditions</a> provide a unique insight into what the sky may have looked like more than 10,000 years ago – and what that teaches us about human history. In Aotearoa, the ongoing revitalisation of <a href="https://www.newshub.co.nz/home/new-zealand/2020/07/the-hui-maramataka-matariki-and-the-revival-of-m-ori-sciences.html">Māori astronomical traditions</a> symbolises the necessary bicultural constitutional foundations, as set out in Te Tiriti o Waitangi, for a rapidly emerging space sector. </p>
<p>This foundation means having authentic partnerships with tangata whenua, the Indigenous peoples. It means ensuring Māori voices are welcomed and respected at the decision-making stage and on what we choose to do in space. </p>
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<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/major-changes-coming-over-the-horizon-for-the-global-space-industry-152289">Major changes coming over the horizon for the global space industry</a>
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<p>Māori are already paving a new way to <a href="https://www.teaonews.co.nz/2023/07/28/helping-rangatahi-reach-for-the-stars/">space</a> and <a href="https://www.nzgcp.co.nz/about-us/news-and-media/resources/what-is-deep-tech-and-why-do-we-invest-in-this/">deep tech</a>. They are <a href="https://www.mbie.govt.nz/science-and-technology/science-and-innovation/international-opportunities/new-zealand-r-d/innovative-partnerships/project-tawhaki/">gaining significant funding</a> and inspiring the next generation of rangatahi (young people) to be space professionals, while simultaneously grounded in their Māori astronomy. Broadening our view of sustainability could be the difference between oppression and recognition of Māori interests in the domestic space sector.</p>
<p>So far, space exploration has been propelled by competition. Throughout history, this has been sustained by cold wars and national pride, without much thought about consequence. But it is time to reconsider this and start to think of space as a commons – something more than just a resource to exploit. Space is something we all have a stake in, together on our pale blue dot.</p>
<p><em>With credit to our co-authors in our research publication: Adam Morris, Nicholas Rattenbury, Cody Mankelow, Alice Gorman, Stevie Katavich-Barton.</em></p><img src="https://counter.theconversation.com/content/211335/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>The authors do not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and have disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Space exploration is often propelled by competition, driven by national pride and with little thought about consequence. It is time to consider space as a commons, not just a resource to exploit.Priyanka Dhopade, Lecturer in Mechanical Engineering, University of Auckland, Waipapa Taumata RauCarolle Varughese, Research Assistant, University of Auckland, Waipapa Taumata RauLena Henry, Lecturer in Creative Arts, Architecture and Planning, University of Auckland, Waipapa Taumata RauSarah Hendrica Bickerton, Lecturer in Public Policy, University of Auckland, Waipapa Taumata RauTe Kahuratai Moko-Painting, Co-Director – Centre for Pūtaiao, University of Auckland, Waipapa Taumata RauLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2111842023-08-08T00:38:18Z2023-08-08T00:38:18ZA spectacular fireball just streaked across Melbourne – but astronomers didn’t see it coming<figure><img src="https://images.theconversation.com/files/541597/original/file-20230808-27645-48m1o0.jpg?ixlib=rb-1.1.0&rect=11%2C0%2C1985%2C1616&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="https://twitter.com/markjdavidson/status/1688662681467998211">Mark Davidson / Twitter</a></span></figcaption></figure><p>The first hours after a fireball sighting are like a detective mystery. Last night around midnight, people across Melbourne took to social media to report sightings of a bright light slowly streaking across the sky.</p>
<p>Video footage clearly shows the fireball break apart, with these fragments in turn burning up, meaning this object was big.</p>
<p><div data-react-class="Tweet" data-react-props="{"tweetId":"1688553695842349057"}"></div></p>
<h2>An unexpected piece of space junk</h2>
<p>There <a href="https://twitter.com/10NewsFirstMelb/status/1688671656284401664">have been reports</a> across Victoria of a loud explosion. Known as <a href="https://www.britannica.com/science/sonic-boom">sonic booms</a>, such sounds imply the pieces survived long enough to enter the lower atmosphere – otherwise they wouldn’t be audible from the ground. In turn, this tells us at least a part of this fireball was dense.</p>
<p><div data-react-class="Tweet" data-react-props="{"tweetId":"1688556188043206656"}"></div></p>
<p>Additionally, the glow of the fireball had clearly discernible colours, particularly orange, in some videos. This tells us the object isn’t a space rock, but is human-made, with a significant amount of plastics or metals burning up (familiar to anyone in high school chemistry class burning materials in the Bunsen burner).</p>
<p>So, it’s likely we just witnessed several tonnes of space junk – anything humans have put into orbit that isn’t under our control any longer – re-enter Earth’s atmosphere. However, nothing was predicted for reentry on the global space debris tracking site <a href="https://www.satview.org/">SatView</a>.</p>
<p>According to <a href="https://twitter.com/planet4589/status/1688701218086952962">an early analysis</a> by US-based astronomer Jonathan McDowell, the fireball may have been the third stage of a Soyuz 2 rocket <a href="https://everydayastronaut.com/glonass-k2-no-13-kosmos-2569-soyuz-2-1b-fregat/">carrying the navigation satellite GLONASS-K2</a>. This was launched by Roscosmos (the Russian space agency) on August 7 from the Plesetsk Cosmodrome about 800km north of Moscow. </p>
<p><div data-react-class="Tweet" data-react-props="{"tweetId":"1688701218086952962"}"></div></p>
<p>The incredible brightness of the fireball is thanks to the tremendous speed at which objects re-enter Earth’s thin upper atmosphere, 25,000 kilometres per hour or more. </p>
<p>When you rub your hands together, they get warm from the friction between them. Do that a thousand times faster and you can start to imagine them glowing white hot from the heat. If the friction is between the metal of the space junk and Earth’s thin atmosphere at an altitude of 100km, we can get a very bright glow. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/satellites-and-space-junk-may-make-dark-night-skies-brighter-hindering-astronomy-and-hiding-stars-from-our-view-202047">Satellites and space junk may make dark night skies brighter, hindering astronomy and hiding stars from our view</a>
</strong>
</em>
</p>
<hr>
<h2>You can help astronomers with the details</h2>
<p>To help us confirm what the fireball was and where it came from, we need witnesses to download the <a href="http://fireballsinthesky.com.au/download-app/">Fireballs in the Sky App</a> and recreate the passage of that trail as best they can.</p>
<p>From all those sightings we can triangulate the trajectory and determine where any surviving pieces might have landed and try to collect them. Reports so far are conflicting and we need more data. It appears it came into the atmosphere from the north-west across Victoria to Tasmania in the south-east, but it’s too soon to tell what its exact path was.</p>
<p><div data-react-class="Tweet" data-react-props="{"tweetId":"1688560558373851136"}"></div></p>
<p>Most space junk doesn’t make it to Earth. The incredible heat of 5,000 Kelvin or greater generated by the re-entry burns up almost all such pieces. </p>
<p>Some hardier engine blocks can make it to the ground, however, which is why alerts about space junk re-entering the atmosphere are sent out to aircraft in particular.</p>
<p>However, space junk travels so fast, even a very small mistake in the calculation of the re-entry will have it show up hundreds of kilometres away instead. For most purposes, such warnings are not as helpful as they could be.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/airplanes-face-a-growing-risk-of-being-hit-by-uncontrolled-re-entries-of-rockets-used-to-launch-satellites-202400">Airplanes face a growing risk of being hit by uncontrolled re-entries of rockets used to launch satellites</a>
</strong>
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<p>To improve this system, we need better tracking stations on the ground and advances in the modelling of the interaction between space junk and the upper atmosphere to improve our forecasts.</p>
<p>Thankfully buildings, let alone people, are <em>tiny</em> targets relative to the vast unpopulated reaches of land and sea. While there <a href="https://en.wikipedia.org/wiki/List_of_space_debris_fall_incidents">have been reported hits</a>, these are thankfully incredibly rare, making space junk hardly a danger for us on Earth. </p>
<p>As astronomers now rush to work out the details of this beautiful fireball, it also marks a spectacular opening for Australia’s <a href="https://www.scienceweek.net.au">National Science Week</a>, with thousands of live talks explaining science as widely as possible, just like this event.</p><img src="https://counter.theconversation.com/content/211184/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Alan Duffy receives funding from the Australian Research Council and is employed at Swinburne University of Technology </span></em></p>A mysterious hunk of space junk buzzed through Australian skies last night. It may have been the third stage of a Soyuz 2 rocket just launched by Russia.Alan Duffy, Director of the Space Technology and Industry Institute, Swinburne University of TechnologyLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2022042023-04-05T19:18:01Z2023-04-05T19:18:01ZHow can we make the space sector more sustainable?<figure><img src="https://images.theconversation.com/files/518447/original/file-20230330-17-2bzlma.jpeg?ixlib=rb-1.1.0&rect=20%2C0%2C1897%2C1474&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">An artist's impression of the 30,000 or so space debris orbiting around the Earth.</span> <span class="attribution"><a class="source" href="https://www.flickr.com/photos/hopeful_in_nj/3273279798">Flickr</a>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span></figcaption></figure><p>When talking about space, one might think about the stars one sees at night or a good sci-fi film. But space is also crowded with satellites, spacecrafts and astronauts, whose missions can last anywhere from several days to months. Meanwhile, <a href="https://www.geospatialworld.net/prime/how-many-satellites-orbiting-earth/">8,216 unmanned satellites</a> revolve around Earth’s orbits to improve our daily lives. Communication satellites contribute to enhancing Internet access in regions deprived of infrastructure (so-called “white areas”); meteorology satellites have become essential for weather forecasts, while navigation satellites (including GPS) are crucial for current and future transportation needs such as automatic driving vehicles.</p>
<p>Technological advances in the sector have unlocked many new business opportunities. The industry can now launch constellations of thousand satellites to reach corners of the earth as it had never before (e.g., <a href="https://theconversation.com/space-junk-astronomers-worry-as-private-companies-push-ahead-with-satellite-launches-137572">Starlink</a>), while new markets such as space mining and space tourism are steadily growing. National champions (including the <a href="https://www.whitehouse.gov/briefing-room/statements-releases/2022/09/09">United States</a> and <a href="https://www.elysee.fr/elysee/module/19326/fr">France</a>) have also framed the space sector as a top economic priority. It is thought the technological benefits accrued by companies such as SpaceX, Blue Origin or OneWeb, launched by billionaires such as Elon Musk, will also be able to trickle down to non-space sectors such as the energy or freight industries.</p>
<h2>Issues for sustainable space</h2>
<p>For all these benefits, civil society appears increasingly concerned about the sector’s ecological footprint.</p>
<p>The first main issue to tackle is <a href="https://theconversation.com/space-debris-what-can-we-do-with-unwanted-satellites-40736">space debris</a> which are defunct human-made objects in Earth orbit that no longer serve a useful function. These objects include non-operating satellites, abandoned parts of launch vehicles, which carry satellites or spacecraft into space, decommissioned satellites, and even debris resulting from the collision between space objects. In practice, this means more than <a href="https://www.esa.int/Space_Safety/Space_Debris/ESA_s_Space_Environment_Report_2022">30,000 harmful space debris</a> and 3,364 non-operating satellites could collide into an estimated 4,859 active operating satellites, with catastrophic implications for our daily lives in sectors spanning transport and security to finance.</p>
<p>Some space activities could also impact the Earth’s environment, including air, water and soil pollution, and outer-space contaminations. Take, for example, the rising popularity of space tourism. Given <a href="https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2021EF002612">soot from spacecrafts currently warms up the Earth</a> at a rate that is 500 times greater than that released by planes, there is growing anxiety over the sector’s associated greenhouse gas emissions and toxic substances. As a result, the debate over space activities cannot be the prerogative of the space community alone.</p>
<p>In an attempt to resolve these issues, our <a href="https://intellectdiscover.com/content/journals/10.1386/tmsd_00063_1">recent research</a> has identified three promising working avenues:</p>
<ul>
<li><p>Collaboration</p></li>
<li><p>Green space technology</p></li>
<li><p>Policies aiming at sustainable development</p></li>
</ul>
<h2>Tailor solutions for sustainable space</h2>
<p>The collaboration needs to be carried out <a href="https://onlinelibrary.wiley.com/doi/full/10.1111/radm.1254">between five key parties</a>: governments, academia, the industry, civil society, and environmental players such as NGOs. Nevertheless, while the industry has already developed an awareness of the issues at stake, the input of academic institutions has yet to be clarified. In particular, academia could provide new ideas in the areas of debris identification and removal, space traffic management, space situational awareness, and in-orbit servicing.</p>
<p>The second solution consists in developing green space technology that would emit less greenhouse gas emissions and other hazardous chemical substances. According to <a href="https://www.esa.int/Space_Safety/Clean_Space/Green_technologies">the European Space Agency</a>, these green technologies could minimise the energy consumption throughout the entire life-cycle of a space mission, save up on resources, while also minimising toxic substances to protect human well-being and biodiversity.</p>
<p>Green space solutions to investigate include space traffic management, in-orbit servicing and active debris removal on the one hand. When it comes to the spacecrafts themselves, scientists should also start to imagine greener propulsion, cleaner fuels, and alternatives to toxic material. For example, following the path of SpaceX, all launch vehicle manufacturers are also considering reusable launchers that will reduce CO<sub>2</sub> gas emission in a life cycle.</p>
<p>The final solution consists in developing policies that can at once encourage space commercialisation and enhance sustainable policy regime. One instance of this are green innovation policies assisting low-carbon small and medium enterprises. It will be important to align these policies with the <a href="https://www.un.org/sustainabledevelopment/">17 pillars of Sustainable Development Goals (SDGs) established by the United Nations</a>. To achieve this agenda, some indicators are emerging such as space sustainability rating and ESG (environment, social and governance).</p>
<p>We think that we are still on time to solve the two main issues in sustainable space: space debris and the sector’s overall ecological impact on Earth. However, space organisations cannot remain idle awaiting that “space shame” – a space version of <em>flight shame</em> (from the original Swedish concept of <a href="https://theconversation.com/flight-shaming-how-to-spread-the-campaign-that-made-swedes-give-up-flying-for-good-133842"><em>flygskam</em></a>) in the aviation sector – propels them into action.</p><img src="https://counter.theconversation.com/content/202204/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Nonthapat Pulsiri has received funding from the SIRIUS Chair.</span></em></p><p class="fine-print"><em><span>Victor Dos Santos Paulino has received funding from the SIRIUS Chair.</span></em></p>How might the space industry reduce its ecological footprint and better manage the debris it leaves in its wake?Nonthapat Pulsiri, Chercheur post-doctorant en stratégie, innovation et entrepreneuriat, Chaire Sirius, TBS EducationVictor Dos Santos Paulino, Professeur associé en management de l'innovation et stratégie, Chaire Sirius, TBS EducationLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1888812022-09-20T12:37:19Z2022-09-20T12:37:19ZMars is littered with 15,694 pounds of human trash from 50 years of robotic exploration<figure><img src="https://images.theconversation.com/files/484934/original/file-20220915-22-fc4dmg.jpg?ixlib=rb-1.1.0&rect=47%2C27%2C1348%2C927&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Rovers on Mars frequently come across debris – like this heat shield and spring – from their own or other missions.</span> <span class="attribution"><a class="source" href="https://mars.nasa.gov/resources/5853/opportunitys-heat-shield-in-color-sol-335/">NASA/JPL-Caltech</a></span></figcaption></figure><figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/485427/original/file-20220919-16-10zrgt.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/485427/original/file-20220919-16-10zrgt.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=255&fit=crop&dpr=1 600w, https://images.theconversation.com/files/485427/original/file-20220919-16-10zrgt.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=255&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/485427/original/file-20220919-16-10zrgt.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=255&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/485427/original/file-20220919-16-10zrgt.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=321&fit=crop&dpr=1 754w, https://images.theconversation.com/files/485427/original/file-20220919-16-10zrgt.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=321&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/485427/original/file-20220919-16-10zrgt.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=321&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption"></span>
<span class="attribution"><a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<p>People have been exploring the surface of Mars for <a href="https://nssdc.gsfc.nasa.gov/nmc/spacecraft/display.action?id=1971-045D">over 50 years</a>. According to the <a href="https://www.unoosa.org/">United Nations Office for Outer Space Affairs</a>, nations have sent <a href="https://www.unoosa.org/oosa/osoindex/search-ng.jspx?lf_id=#?c=%7B%22filters%22:%5B%7B%22fieldName%22:%22en%23object.status.objectStatus_s1%22,%22value%22:%22*mars*%22%7D%5D,%22sortings%22:%5B%7B%22fieldName%22:%22object.launch.dateOfLaunch_s1%22,%22dir%22:%22desc%22%7D%5D,%22match%22:%22%22,%22termMatch%22:%22mars%22%7D">18 human-made objects to Mars</a> over 14 separate missions. Many of these missions are still ongoing, but over the decades of Martian exploration, humankind has left behind many pieces of debris on the planet’s surface.</p>
<p>I am a <a href="https://scholar.google.com/citations?user=ASOEoQcAAAAJ&hl=en&oi=ao">postdoctoral research fellow</a> who studies ways to track Mars and Moon rovers. In mid-August 2022, NASA confirmed that the Mars rover Perseverance had spotted a piece of trash jettisoned during its landing, this time a tangled mess of netting. And this is not the first time scientists have found trash on Mars. That’s because there is a lot there. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/484932/original/file-20220915-20879-l0jt2j.png?ixlib=rb-1.1.0&rect=227%2C654%2C2208%2C1605&q=45&auto=format&w=1000&fit=clip"><img alt="A smashed, round, white metal object on the surface of Mars." src="https://images.theconversation.com/files/484932/original/file-20220915-20879-l0jt2j.png?ixlib=rb-1.1.0&rect=227%2C654%2C2208%2C1605&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/484932/original/file-20220915-20879-l0jt2j.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=438&fit=crop&dpr=1 600w, https://images.theconversation.com/files/484932/original/file-20220915-20879-l0jt2j.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=438&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/484932/original/file-20220915-20879-l0jt2j.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=438&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/484932/original/file-20220915-20879-l0jt2j.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=551&fit=crop&dpr=1 754w, https://images.theconversation.com/files/484932/original/file-20220915-20879-l0jt2j.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=551&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/484932/original/file-20220915-20879-l0jt2j.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=551&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">All spacecraft that land on Mars eject equipment – like this protective shell – on their way to the Martian surface.</span>
<span class="attribution"><a class="source" href="https://mars.nasa.gov/mars2020/mission/status/394/images-of-edl-debris/">NASA/JPL-Caltech</a></span>
</figcaption>
</figure>
<h2>Where does the debris come from?</h2>
<p>Debris on Mars comes from three main sources: discarded hardware, inactive spacecraft and crashed spacecraft.</p>
<p>Every mission to the Martian surface requires a <a href="https://mars.nasa.gov/resources/25489/perseverance-rovers-entry-descent-and-landing-profile/">module</a> that protects the spacecraft. This module includes a heat shield for when the craft passes through the planet’s atmosphere and a parachute and landing hardware so that it can land softly.</p>
<p>The craft discards pieces of the module as it descends, and these pieces can land in different locations on the planet’s surface – there may be a lower heat shield in one place and a parachute in another. When this debris crashes to the ground, it can break into smaller pieces, as <a href="https://mars.nasa.gov/resources/26694/rovers-backshell-seen-from-the-air/">happened during the Perseverance rover landing in 2021</a>. These small pieces can then get blown around because of Martian winds.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/484935/original/file-20220915-6106-xqvfbp.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A small tangled piece of netting on the surface of Mars." src="https://images.theconversation.com/files/484935/original/file-20220915-6106-xqvfbp.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/484935/original/file-20220915-6106-xqvfbp.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=448&fit=crop&dpr=1 600w, https://images.theconversation.com/files/484935/original/file-20220915-6106-xqvfbp.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=448&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/484935/original/file-20220915-6106-xqvfbp.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=448&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/484935/original/file-20220915-6106-xqvfbp.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=563&fit=crop&dpr=1 754w, https://images.theconversation.com/files/484935/original/file-20220915-6106-xqvfbp.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=563&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/484935/original/file-20220915-6106-xqvfbp.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=563&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">The Perseverance rover came across this piece of netting on July 12, 2022, more than a year after landing on Mars.</span>
<span class="attribution"><a class="source" href="https://mars.nasa.gov/mars2020/multimedia/raw-images/FLF_0495_0710900226_737ECM_N0261004FHAZ02008_10_095J">NASA/JPL-Caltech</a></span>
</figcaption>
</figure>
<p>A lot of small, windblown trash has been found over the years – like the <a href="https://mars.nasa.gov/mars2020/multimedia/raw-images/FLF_0495_0710900226_737ECM_N0261004FHAZ02008_10_095J">netting material</a> found recently. Earlier in the year, on June 13, 2022, Perseverance rover spotted a large, shiny thermal blanket wedged in some rocks 1.25 miles (2 km) from where the rover landed. Both <a href="https://mars.nasa.gov/resources/4806/small-debris-on-the-ground-beside-curiosity/?site=msl">Curiosity in 2012</a> and <a href="https://mars.nasa.gov/resources/5853/opportunitys-heat-shield-in-color-sol-335/">Opportunity in 2005</a> also came across debris from their landing vehicles.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/484941/original/file-20220915-22-ne76pe.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Three photos showing black soot and debris from above." src="https://images.theconversation.com/files/484941/original/file-20220915-22-ne76pe.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/484941/original/file-20220915-22-ne76pe.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=761&fit=crop&dpr=1 600w, https://images.theconversation.com/files/484941/original/file-20220915-22-ne76pe.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=761&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/484941/original/file-20220915-22-ne76pe.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=761&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/484941/original/file-20220915-22-ne76pe.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=957&fit=crop&dpr=1 754w, https://images.theconversation.com/files/484941/original/file-20220915-22-ne76pe.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=957&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/484941/original/file-20220915-22-ne76pe.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=957&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">The European Space Agency’s Schiaparelli lander crashed onto the surface of Mars in 2016, as seen in these photos of the crash site captured by NASA’s Mars Reconnaissance Orbiter.</span>
<span class="attribution"><a class="source" href="https://www.jpl.nasa.gov/images/pia21132-schiaparelli-impact-site-on-mars-in-color">NASA/JPL-Caltech/Univ. of Arizona</a></span>
</figcaption>
</figure>
<h2>Dead and crashed spacecraft</h2>
<p>The <a href="https://nssdc.gsfc.nasa.gov/nmc/SpacecraftQuery.jsp">nine inactive spacecraft on the surface of Mars</a> make up the next type of debris. These craft are the Mars 3 lander, Mars 6 lander, Viking 1 lander, Viking 2 lander, the Sojourner rover, the <a href="https://www.esa.int/Science_Exploration/Space_Science/Mars_Express/Beagle-2_lander_found_on_Mars">formerly lost Beagle 2 lander</a>, the Phoenix lander, the Spirit rover and the most recently deceased spacecraft, the Opportunity rover. Mostly intact, these might be better considered historical relics than trash.</p>
<p>Wear and tear take their toll on everything on the Martian surface. Some parts of <a href="https://www.planetary.org/articles/08190630-curiosity-wheel-damage">Curiosity’s aluminum wheels have broken off</a> and are presumably scattered along the rover’s track. Some of the litter is purposeful, with Perseverance <a href="https://mars.nasa.gov/mars2020/multimedia/raw-images/ZL0_0353_0698274371_400EBY_N0095676ZCAM05098_1100LMJ">having dropped a drill bit onto the surface</a> in July 2021, allowing it to <a href="https://twitter.com/NASAPersevere/status/1418673630427287554">swap in a new, pristine bit</a> so that it could keep collecting samples. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/484939/original/file-20220915-1785-94oijc.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A photo of the wheels of Curiosity rover with holes visible." src="https://images.theconversation.com/files/484939/original/file-20220915-1785-94oijc.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/484939/original/file-20220915-1785-94oijc.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/484939/original/file-20220915-1785-94oijc.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/484939/original/file-20220915-1785-94oijc.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/484939/original/file-20220915-1785-94oijc.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/484939/original/file-20220915-1785-94oijc.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/484939/original/file-20220915-1785-94oijc.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=566&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">The wheels of the Curiosity rover have taken damage over the years, leaving behind small bits of aluminum.</span>
<span class="attribution"><a class="source" href="https://www.nasa.gov/specials/wheels/img/curiosity_tire_damage.jpg">NASA/JPL-Caltech</a></span>
</figcaption>
</figure>
<p>Crashed spacecraft and their pieces are another significant source of trash. At least two spacecraft have crashed, and an additional four have lost contact before or just after landing. Safely descending to the planet’s surface is the hardest part of any Mars landing mission – and it <a href="https://www.jpl.nasa.gov/images/pia21132-schiaparelli-impact-site-on-mars-in-color">doesn’t always end well</a>. </p>
<p>When you add up the mass of all spacecraft that have ever been sent to Mars, you get about 22,000 pounds (9979 kilograms). Subtract the weight of the currently operational craft on the surface – 6,306 pounds (2,860 kilograms) – and you are left with 15,694 pounds (7,119 kilograms) of human debris on Mars.</p>
<h2>Why does trash matter?</h2>
<p>Today, the main concern scientists have about trash on Mars is the risk it poses to current and future missions. The Perseverance teams are documenting all debris they find and checking to see if any of it could contaminate the samples the rover is collecting. NASA engineers have also considered whether Perseverance could get tangled in debris from the landing but have <a href="https://mars.nasa.gov/mars2020/mission/status/394/images-of-edl-debris/">concluded the risk is low</a>. </p>
<p>The real reason debris on Mars is important is because of its place in history. The spacecraft and their pieces are the early milestones for human planetary exploration.</p><img src="https://counter.theconversation.com/content/188881/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Cagri Kilic does not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Discarded pieces of landing gear, crashed spacecraft and wear and tear have produced a lot of debris that is now scattered around the Martian surface.Cagri Kilic, Postdoctoral Research Fellow in Robotics, West Virginia UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1896982022-09-13T00:25:26Z2022-09-13T00:25:26ZHarpoons, robots and lasers: how to capture defunct satellites and other space junk and bring it back to Earth<figure><img src="https://images.theconversation.com/files/483371/original/file-20220908-13-xvfxf0.png?ixlib=rb-1.1.0&rect=4%2C79%2C1422%2C712&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><span class="source">European Space Agency</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span></figcaption></figure><p>More than half of the thousands of satellites in orbit are now defunct, and this accumulation of floating space debris has been described as a “<a href="https://www.frontiersin.org/articles/10.3389/frspt.2022.792944/full">fatal problem</a>” for current and future space missions and human space travel. </p>
<p>An estimated 130 million objects smaller than 1cm and 34,000 larger than 10cm are travelling in orbit at speeds of thousands of kilometres per hour, according to the European Space Agency (<a href="https://www.esa.int/">ESA</a>). A report presented at this year’s <a href="https://space-debris-conference.sdo.esoc.esa.int/page/welcome">European conference on space debris</a> suggests the amount of space junk could increase fifty-fold by 2100. </p>
<p>While many fragments of space junk are small, they travel so fast their impact has enough energy to disable a satellite or cause significant damage to space stations.</p>
<p>Both the Hubble Telescope and the Solar Maximum Mission (<a href="https://solarscience.msfc.nasa.gov/SMM.shtml">SMM</a>) satellites had coin-sized holes punched into them by flying debris and a mirror on Nasa’s James Webb space telescope was <a href="https://www.space.com/james-webb-space-telescope-suffers-micrometeoroid-impacts">damaged by micrometeoroids</a>. </p>
<p>Most satellites were not designed with the end of their usefulness in mind. About 60% of the 6,000 satellites in orbit are now out of order. Along with the smaller objects these defunct satellites constitute a major problem both for existing and future satellites and space stations. </p>
<figure class="align-center ">
<img alt="SpaceX Falcon 9 rocket launches the company's third Starlink mission." src="https://images.theconversation.com/files/483886/original/file-20220912-16-sqiz1w.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/483886/original/file-20220912-16-sqiz1w.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=372&fit=crop&dpr=1 600w, https://images.theconversation.com/files/483886/original/file-20220912-16-sqiz1w.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=372&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/483886/original/file-20220912-16-sqiz1w.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=372&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/483886/original/file-20220912-16-sqiz1w.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=467&fit=crop&dpr=1 754w, https://images.theconversation.com/files/483886/original/file-20220912-16-sqiz1w.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=467&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/483886/original/file-20220912-16-sqiz1w.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=467&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">SpaceX’s Starlink mission plans to put a constellation of thousands of satellites into orbit to improve internet services around the world.</span>
<span class="attribution"><span class="source">Paul Hennessy/NurPhoto via Getty Images</span></span>
</figcaption>
</figure>
<p>Mega constellations of satellites currently being sent into space by corporations such as SpaceX and Amazon are expected to transform access to the internet for all countries. But these private telecommunications ventures will also contribute 50,000 more satellites to already dangerously populated orbits. </p>
<p>Scientists have warned the rapid development of mega constellations risks several “<a href="https://www.nature.com/articles/s41598-021-89909-7">tragedies of the commons</a>”, including to ground-based astronomy, Earth’s orbit and Earth’s upper atmosphere. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/soon-1-out-of-every-15-points-of-light-in-the-sky-will-be-a-satellite-170427">Soon, 1 out of every 15 points of light in the sky will be a satellite</a>
</strong>
</em>
</p>
<hr>
<h2>Methods to remove space debris</h2>
<p>There is a growing concern, described as the <a href="https://www.techtarget.com/whatis/definition/Kessler-Syndrome">Kessler Syndrome</a>, that we may be creating an envelope of space debris which could prevent human space travel, space exploration and the use of satellites in some parts of Earth’s orbit. This scenario, perpetuated by collisions between space objects creating ever more debris, could also damage our global communications and navigation systems. </p>
<p>This is why the development of practical debris removal technologies is important and urgent. So far, various strategies have been conceptualised to solve the space debris problem and some have been recently <a href="https://www.frontiersin.org/articles/10.3389/frspt.2022.792944/full">prioritised</a>. </p>
<p><img src="https://cdn.theconversation.com/static_files/files/2307/Space_debris.gif?1663021030" width="100%"> </p>
<p>To date, not a single orbiting object has been recovered from space successfully. </p>
<p>One of the main problems in designing space debris removal strategies is how to transfer the energy between the debris (target) and the chaser during the first contact. There are two prioritised approaches and a third in development: </p>
<ul>
<li><p>Impact energy dissipation methods seek to decrease the impact energy of the debris. In one approach, the chaser satellite deploys a harpoon to penetrate the space debris. After the successful shot, the chaser satellite, harpoon and target would become connected by an elastic tether and the chaser would pull the debris to re-enter the atmosphere and burn up together. </p></li>
<li><p>Neutral energy balance includes a magnetic capture method which uses magnetic coils to achieve perfect energy balance between chaser and target. This is a soft docking method which is a preliminary step to some subsequent method of debris disposal. </p></li>
<li><p>Destructive energy absorption aims to destroy small debris targets using a high-powered laser. But the challenge is to develop a laser and battery combination that is powerful but lightweight enough. A laboratory in China has been developing a space-based laser system to be installed on a chaser satellite capable of targeting debris of up to 20cm in size. The <a href="https://ntrs.nasa.gov/citations/19960054373">Nasa Orion project</a> uses ground-based lasers to destroy small debris.</p></li>
</ul>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/a-chunk-of-chinese-satellite-almost-hit-the-international-space-station-they-dodged-it-but-the-space-junk-problem-is-getting-worse-171735">A chunk of Chinese satellite almost hit the International Space Station. They dodged it – but the space junk problem is getting worse</a>
</strong>
</em>
</p>
<hr>
<figure class="align-right ">
<img alt="A ClearSpace chaser is designed to use robotic arms to capture space debris." src="https://images.theconversation.com/files/484150/original/file-20220912-18-aifa2q.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/484150/original/file-20220912-18-aifa2q.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=902&fit=crop&dpr=1 600w, https://images.theconversation.com/files/484150/original/file-20220912-18-aifa2q.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=902&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/484150/original/file-20220912-18-aifa2q.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=902&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/484150/original/file-20220912-18-aifa2q.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1133&fit=crop&dpr=1 754w, https://images.theconversation.com/files/484150/original/file-20220912-18-aifa2q.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1133&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/484150/original/file-20220912-18-aifa2q.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1133&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">A ClearSpace chaser is designed to use robotic arms to capture space debris.</span>
<span class="attribution"><span class="source">ESA</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<p>The <a href="https://www.esa.int/Space_Safety/ESA_purchases_world-first_debris_removal_mission_from_start-up">first space removal project</a> is scheduled for 2025 and will be led by the ESA. It involves a consortium approach based on a Swiss spinoff company, <a href="https://clearspace.today/">ClearSpace</a>. </p>
<p>The ClearSpace chaser will rendezvous with the target and capture it using four robotic arms. The chaser and captured launcher will then be de-orbited and burn up in the atmosphere. </p>
<h2>High cost and more pollution</h2>
<p>A key challenge is the substantial cost associated with these proposed solutions, given the immense scale of the space debris problem. Another important aspect is the potential impact of space-clearing efforts on our planet’s atmosphere. </p>
<p>The idea that a growing number of satellites and other objects would be incinerated in the atmosphere as they are removed from space <a href="https://www.nytimes.com/2021/05/12/science/space-junk-climate-change.html">concerns climate scientists</a>. Space debris is pulled downward naturally and burns up in the lower atmosphere, but increasing levels of carbon dioxide are <a href="https://www.nsf.gov/news/news_summ.jsp?cntn_id=108187">reducing the density</a> of the upper atmosphere, which could <a href="https://www.scienceabc.com/nature/universe/how-does-space-debris-impact-earths-environment-and-atmosphere.html">diminish its capacity</a> to pull debris back towards Earth. </p>
<p>The combustion of more and more satellites and other space debris (80 tonnes per year at present) falling either naturally or via the new removal methods will also release decomposition products into the atmosphere. </p>
<p>These will certainly contribute more carbon dioxide and other greenhouse gases. The decomposition of certain materials in satellites is also likely to release chlorofluorocarbon (CFC) gases, which could damage the ozone shield. </p>
<p>One cannot miss the parallels between the space junk problem and waste recycling. Clearly, we need to devise a circular economy strategy for our space waste. </p>
<p>At present the <a href="https://space.stackexchange.com/questions/52205/who-owns-space-junk">legal responsibility for space debris</a> lies with the country of origin. This seems to militate against future international cooperative programmes of space junk removal.</p><img src="https://counter.theconversation.com/content/189698/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Ralph Cooney does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>To date, not a single orbiting object has been recovered from space successfully. But several methods are in development to reduce the overpopulation of Earth’s orbit by man-made debris.Ralph Cooney, Professor Emeritus in Advanced Materials, University of Auckland, Waipapa Taumata RauLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1880622022-08-03T05:53:55Z2022-08-03T05:53:55ZSpace debris is coming down more frequently. What are the chances it could hit someone or damage property?<figure><img src="https://images.theconversation.com/files/477304/original/file-20220803-16-ifgx3d.png?ixlib=rb-1.1.0&rect=15%2C7%2C2522%2C1689&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><span class="source">Brad Tucker</span>, <span class="license">Author provided</span></span></figcaption></figure><p>In the past week alone, we’ve seen two separate incidents of space debris hurtling back to Earth in unexpected places. </p>
<p>On Saturday there was the uncontrolled re-entry of a Chinese Long March 5B rocket over Malaysia. Yesterday outlets reported on some spacecraft parts that <a href="https://www.theguardian.com/science/2022/aug/01/like-an-alien-obelisk-space-debris-found-in-snowy-mountains-paddock-believed-to-be-from-spacex-mission">turned up</a> in regional New South Wales – now <a href="https://www.abc.net.au/news/2022-08-03/space-x-debris-sheep-paddock-australian-space-agency/101295488">confirmed</a> to be from a SpaceX Crew-1 mission.</p>
<p>As the space industry grows, it’s safe to say such incidents will only become more frequent – and they could pose a risk. But how much of a risk, exactly?</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/477299/original/file-20220803-12-muh9eq.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A Long March 5B rocket is staioned, ready for takeoff." src="https://images.theconversation.com/files/477299/original/file-20220803-12-muh9eq.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/477299/original/file-20220803-12-muh9eq.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/477299/original/file-20220803-12-muh9eq.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/477299/original/file-20220803-12-muh9eq.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/477299/original/file-20220803-12-muh9eq.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/477299/original/file-20220803-12-muh9eq.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/477299/original/file-20220803-12-muh9eq.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">The Long March 5B Y3 carrier rocket was launched from the Wenchang Space Launch Centre in China’s Hainan province on July 24. Some of its debris fell into the Indian Ocean on Saturday.</span>
<span class="attribution"><span class="source">Li Gang/AP</span></span>
</figcaption>
</figure>
<h2>Chunks of metal hurtling towards us</h2>
<p>Space debris refers to the leftover components of a space system that are no longer required. It might be a satellite that has reached the end of its life (such as the International Space Station), or parts of a rocket system that have fulfilled their purpose and are discarded.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/the-international-space-station-is-set-to-come-home-in-a-fiery-blaze-and-australia-will-likely-have-a-front-row-seat-176690">The International Space Station is set to come home in a fiery blaze – and Australia will likely have a front row seat</a>
</strong>
</em>
</p>
<hr>
<p>To date, China has launched three Long March 5B rockets, and each has been deliberately left in an uncontrolled orbit. This means there was no way of knowing where they would land.</p>
<p>As for the SpaceX debris found in the Snowy Mountains, SpaceX de-orbits its rocket parts in a controlled fashion, and designs other components to burn up upon re-entry into Earth’s atmosphere. But as you can see from the latest news, these things don’t always go to plan.</p>
<p>So how dangerous is space debris, really?</p>
<p>Well, as far as we know only one person has ever been hit by it. Lottie Williams, a resident of Tulsa, Oklahoma, <a href="https://abcnews.go.com/Technology/story?id=98700&page=1">was</a> <a href="https://www.npr.org/2011/09/21/140641362/where-falling-satellite-lands-is-anyones-guess">struck</a> by a piece in 1997. It was about the size of her hand and thought to have come from a Delta II rocket. She picked it up, took it home and reported it to authorities the next day.</p>
<p>However, with more and more objects going into space, and coming back down, the chances of someone or something being struck are increasing. This is especially true of large, uncontrolled objects such as the Long March 5B. </p>
<p>Of the three times this model of rocket has been launched:</p>
<ul>
<li>the first re-entered on May 11 2020, with components landing on an <a href="https://room.eu.com/news/debris-from-chinas-rocket-may-have-hit-african-villages">African village</a></li>
<li>the second re-entered on May 9 2021, <a href="https://www.nytimes.com/2021/05/08/science/china-rocket-reentry-falling-long-march-5b.html">near the Maldives</a></li>
<li>the third re-entered on Saturday <a href="https://www.space.com/chinese-long-march-5b-rocket-space-debris-crash">over Indonesia and Malaysia</a>, with debris landing around these islands. </li>
</ul>
<h2>So should I be worried?</h2>
<p>There are many different estimates of the chances of space debris hitting someone, but most are in the <a href="https://www.nature.com/articles/s41550-022-01718-8">one-in-10,000</a> range. This is the chance of <em>any</em> person being hit, anywhere in the world. However, the chances of a <em>particular</em> person being hit (such as you or me) is in the order of <a href="https://aerospace.org/article/satellite-reentry-manipulating-plunge">one in a trillion</a>. </p>
<p>There are several factors behind these estimates, but let’s just focus on one key one for now. The image below shows the orbital path the recent Long March 5B-Y3 rocket followed for its final 24 hours (different objects take different orbital paths), as well as its re-entry location marked in red.</p>
<p>As you can see, the rocket orbits above land for a substantial amount of time. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/477111/original/file-20220802-26-xdtl9v.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/477111/original/file-20220802-26-xdtl9v.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=300&fit=crop&dpr=1 600w, https://images.theconversation.com/files/477111/original/file-20220802-26-xdtl9v.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=300&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/477111/original/file-20220802-26-xdtl9v.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=300&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/477111/original/file-20220802-26-xdtl9v.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=377&fit=crop&dpr=1 754w, https://images.theconversation.com/files/477111/original/file-20220802-26-xdtl9v.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=377&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/477111/original/file-20220802-26-xdtl9v.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=377&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Orbits of the last 24 hours of the Long March 3B-Y3 stage. The red star indicates the approximate re-entry location.</span>
</figcaption>
</figure>
<p>Specifically, in these orbits the vehicle spends about 20% of its time over land. A broad estimate tells us 20% of land is inhabited, which means there is a 4% chance of the Long March 5B re-entry occurring over an inhabited area. </p>
<p>This may seem pretty high. But when you consider how much “inhabited land” is actually covered by people, the likelihood of injury or death becomes significantly less. </p>
<p>The chance of damage to property, on the other hand, is higher. It could be as high as 1% for any given re-entry of the Long March 5B. </p>
<p>Also, the overall risk posed by space debris will increase with the sheer number of objects being launched and re-entering the atmosphere. Current plans of companies and space agencies around the world involve many, many more launches. </p>
<p>China’s Tiangong Space Station is <a href="https://www.bbc.com/news/world-asia-china-61511546">due to</a> be finished by the end of the year. And South Korea recently <a href="https://thediplomat.com/2022/07/south-koreas-space-program-is-a-big-deal/">became</a> the seventh country to launch a satellite payload heavier than one tonne – with plans to <a href="https://thediplomat.com/2022/07/south-koreas-space-program-is-a-big-deal">expand</a> its space sector (<a href="https://www.nature.com/articles/d41586-022-01252-7">along with</a> Japan, Russia, India and United Arab Emirates).</p>
<p>It’s highly likely the chances of being hit are only going to go up (but will hopefully remain very small).</p>
<h2>How can we be prepared?</h2>
<p>Two questions come to mind:</p>
<ol>
<li>can we predict debris re-entries?</li>
<li>what can we do to reduce risk? </li>
</ol>
<p>Let’s start with predictions. It can be extremely challenging to predict where an object in an uncontrolled orbit will re-enter Earth’s atmosphere. The general rule of thumb says uncertainty of the estimated re-entry time will be between 10% and 20% of the remaining orbital time. </p>
<p>This means an object with a predicted re-entry time in ten hours will have an uncertainty margin of about one hour. So if an object is orbiting Earth every 60-90 minutes, it could enter pretty much anywhere. </p>
<p>Improving on this uncertainty margin is a big challenge and will require significant amounts of research. Even then, it’s unlikely we’ll be able to predict an object’s re-entry location more accurately than within a 1,000km range.</p>
<p><div data-react-class="Tweet" data-react-props="{"tweetId":"1553342214474207236"}"></div></p>
<h2>Ways to reduce risk</h2>
<p>Reducing risk is a challenge, but there are a couple of options. </p>
<p>First, all objects launched into an Earth orbit should have a plan for safe de-orbiting into an unpopulated area. This is usually the SPOUA (South Pacific Ocean Uninhabited Area) – also known as the “spacecraft cemetery”.</p>
<p>There’s also the option to carefully design components so they completely disintegrate upon re-entry. If everything burns up when it hits the upper atmosphere, there will no longer be a significant risk.</p>
<p>There are already some guidelines requiring space debris risk minimisation, such as the <a href="https://www.unoosa.org/res/oosadoc/data/documents/2018/aac_1052018crp/aac_1052018crp_20_0_html/AC105_2018_CRP20E.pdf">United Nations guidelines</a> for the Long-term Sustainability of Outer Space Activities – but the mechanisms for these aren’t specified. </p>
<p>Moreover, how do these guidelines apply internationally, and who can enforce them? Such questions remain unanswered.</p>
<p>In summary, should you be concerned about being hit by space debris? For now, no. Is further research on space debris important for the future? Absolutely.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/its-not-how-big-your-laser-is-its-how-you-use-it-space-law-is-an-important-part-of-the-fight-against-space-debris-158790">It's not how big your laser is, it's how you use it: space law is an important part of the fight against space debris</a>
</strong>
</em>
</p>
<hr>
<img src="https://counter.theconversation.com/content/188062/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Fabian Zander receives funding from the Australian Research Council. </span></em></p>As far as we know, only one person has ever been directly struck by space debris. That was back in 1997.Fabian Zander, Senior Research Fellow in Aerospace Engineering, University of Southern QueenslandLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1866662022-07-25T17:18:45Z2022-07-25T17:18:45ZScientists calculate the risk of someone being killed by space junk<figure><img src="https://images.theconversation.com/files/475439/original/file-20220721-13094-8flfis.jpg?ixlib=rb-1.1.0&rect=0%2C0%2C4089%2C2152&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/space-debris-around-planet-earth-1943915647">Frame Stock Footage/Shutterstock</a></span></figcaption></figure><p>The chance of someone being killed by space junk falling from the sky may seem ridiculously tiny. After all, nobody has yet died from such an accident, though there have been instances of injury and damage to property. But given that we are launching an increasing number of satellites, rockets and probes into space, do we need to start taking the risk more seriously?</p>
<p>A new study, <a href="https://www.nature.com/articles/s41550-022-01718-8">published in Nature Astronomy</a>, has estimated the chance of causalities from falling rocket parts over the next ten years. </p>
<p>Every minute of every day, debris rains down on us from space – a hazard we are almost completely unaware of. The microscopic particles from asteroids and comets patter down through the atmosphere to settle unnoticed on the Earth’s surface – adding up to around 40,000 tonnes of dust each year.</p>
<p>While this is not a problem for us, such debris can do damage to spacecraft - as was recently <a href="https://arxiv.org/ftp/arxiv/papers/2207/2207.05632.pdf">reported for the James Webb space telescope</a>. Occasionally, a larger sample arrives as a <a href="https://theconversation.com/how-scientists-found-rare-fireball-meteorite-pieces-on-a-driveway-and-what-they-could-teach-us-156690">meteorite</a>, and maybe once every 100 years or so, a body tens of metres across manages to drive through the atmosphere to excavate a crater. </p>
<p>And – fortunately very rarely – <a href="https://theconversation.com/dont-look-up-several-asteroids-are-heading-towards-earth-heres-how-we-deal-with-threats-in-real-life-174512">kilometre-sized objects</a> can make it to the surface, causing death and destruction – as shown by the lack of dinosaurs roaming the Earth today. These are examples of natural space debris, the uncontrolled arrival of which is unpredictable and spread more or less evenly across the globe.</p>
<p>The new study, however, investigated the uncontrolled arrival of artificial space debris, such as spent rocket stages, associated with rocket launches and satellites. Using mathematical modelling of the inclinations and orbits of rocket parts in space and population density below them, as well as 30 years’ worth of past satellite data, the authors estimated where rocket debris and other pieces of space junk land when they fall back to Earth. </p>
<p>They found that there is a small, but significant, risk of parts re-entering in the coming decade. But this is more likely to happen over southern latitudes than northern ones. In fact, the study estimated that rocket bodies are approximately three times more likely to land at the latitudes of Jakarta in Indonesia, Dhaka in Bangladesh or Lagos in Nigeria than those of New York in the US, Beijing in China or Moscow in Russia.</p>
<p>The authors also calculated a “casualty expectation” — the risk to human life — over the next decade as a result of uncontrolled rocket re-entries. Assuming that each re-entry spreads lethal debris over an area of ten square metres, they found that there is a 10% chance of one or more casualties over the next decade, on average.</p>
<p>To date, the potential for debris from satellites and rockets to cause harm at the Earth’s surface (or in the atmosphere to air traffic) has been regarded as negligible. Most studies <a href="https://www.esa.int/Space_Safety/Space_Debris/The_current_state_of_space_debris#:%7E:text=%E2%80%9CThe%20biggest%20contributor%20to%20the,the%20number%20of%20such%20events">of such space debris</a> have focused on the risk generated in orbit by defunct satellites which might obstruct the safe operation of functioning satellites. Unused fuel and batteries also lead to explosions in orbit which generate additional waste. </p>
<p>But as the number of entries into the rocket launch business increases - and moves from government to private enterprise - it is highly likely that the number of accidents, both in space and on Earth, such as that which followed the launch of the <a href="https://www.space.com/chinese-rocket-booster-long-march-5b-space-junk-crash">Chinese Long March 5b</a>, will also increase. The new study warns that the 10% figure is therefore a conservative estimate.</p>
<h2>What can be done</h2>
<p>There are a range of technologies that make it entirely possible to control the re-entry of debris, but they are expensive to implement. For example, spacecraft can be “passivated”, whereby unused energy (such as fuel or batteries) is expended rather than stored once the lifetime of the spacecraft has ended. </p>
<p>The choice of orbit for a satellite can also reduce the chance of producing debris. A defunct satellite can be programmed to move into low Earth orbit, where it will burn up. </p>
<figure class="align-center ">
<img alt="Image of Saudi officials inspect a crashed module in January 2001." src="https://images.theconversation.com/files/475440/original/file-20220721-10058-au1ju6.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/475440/original/file-20220721-10058-au1ju6.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/475440/original/file-20220721-10058-au1ju6.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/475440/original/file-20220721-10058-au1ju6.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/475440/original/file-20220721-10058-au1ju6.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=565&fit=crop&dpr=1 754w, https://images.theconversation.com/files/475440/original/file-20220721-10058-au1ju6.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=565&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/475440/original/file-20220721-10058-au1ju6.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=565&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Saudi officials inspect a crashed module in January 2001.</span>
<span class="attribution"><span class="source">wikipedia</span></span>
</figcaption>
</figure>
<p>There are also attempts to launch re-usable rockets which, for example, <a href="https://www.spacex.com/">SpaceX</a> has demonstrated and <a href="https://www.blueorigin.com/new-glenn/">Blue Origin</a> is developing. These create a lot less debris, though there will be some from paint and metal shavings, as they return to Earth in a controlled way.</p>
<p>Many agencies do take the risks seriously. The European Space Agency is planning a mission to <a href="https://clearspace.today/">attempt the capture and removal of space debris</a> with a <a href="https://www.space.com/esa-startup-clearspace-debris-removal-2025">four-armed robot</a>. The UN, through its Office of Outer Space Affairs, issued a set of <a href="https://www.unoosa.org/pdf/publications/st_space_49E.pdf">Space Debris Mitigation Guidelines</a> in 2010, which was <a href="https://www.unoosa.org/res/oosadoc/data/documents/2018/aac_1052018crp/aac_1052018crp_20_0_html/AC105_2018_CRP20E.pdf">reinforced in 2018</a>. However, as the authors behind the new study point out, these are guidelines, not international law, and do not give specifics as to how mitigation activities should be implemented or controlled.</p>
<p>The study argues that advancing technologies and more thoughtful mission design would reduce the rate of uncontrolled re-entry of spacecraft debris, decreasing the hazard risk across the globe. It states that “uncontrolled rocket body reentries constitute a collective action problem; solutions exist, but every launching state must adopt them.”</p>
<p>A requirement for governments to act together is not unprecedented, as shown by the agreement to ban ozone layer-destroying chlorofluorcarbon chemicals. But, rather sadly, this kind of action usually requires a major event with significant consequences for the northern hemisphere before action is taken. And changes to international protocols and conventions take time.</p>
<p>In five years, it will be 70 years since the <a href="https://nssdc.gsfc.nasa.gov/nmc/spacecraft/display.action?id=1957-001B#:%7E:text=Description,of%20the%20former%20Soviet%20Union.">launch of the first satellite</a> into space. It would be a fitting celebration of that event if it could be marked by a strengthened and mandatory international treaty on space debris, ratified by all UN states. Ultimately, all nations would benefit from such an agreement.</p><img src="https://counter.theconversation.com/content/186666/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Monica Grady receives funding from STFC and the UK Space Agency. As well as Professor of Planetary and Sapce Sciences at the Open University, she is Chancellor of Liverpool Hope University and a Senior Research Fellow at the Natural History Museum. Follow her on twitter @MonicaGrady</span></em></p>The southern hemisphere is more likely to be hit by space debris than the northern one.Monica Grady, Professor of Planetary and Space Sciences, The Open UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1766902022-02-15T03:42:22Z2022-02-15T03:42:22ZThe International Space Station is set to come home in a fiery blaze – and Australia will likely have a front row seat<figure><img src="https://images.theconversation.com/files/446192/original/file-20220214-19-z6fu9c.jpeg?ixlib=rb-1.1.0&rect=13%2C17%2C2982%2C1926&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><span class="source">Shutterstock</span></span></figcaption></figure><p>For more than two decades the International Space Station (ISS) has been the mainstay of human presence and research in space. More than 100 metres long, it’s the largest object ever placed in space, and its construction brought together the space agencies from the United States, Europe, Russia, Japan and Canada.</p>
<p>The ISS has hosted research that could not have been done anywhere else, in the fields of microgravity, space biology, human physiology and fundamental physics. It also provides a base for deep space exploration.</p>
<p>Now, the end of its life has been planned. <a href="https://www.space.com/how-to-destroy-a-space-station-safely">According to NASA</a>, the station is expected to be de-orbited by 2031 (an extension from the original plan to de-orbit by 2020). But if the ISS is so important, why is there an end-of-life plan at all?</p>
<h2>In short, the ISS is getting old</h2>
<p>The first components of the ISS were launched in the 1990s. And although many parts have been updated and replaced, it’s not feasible to replace everything. </p>
<p>In particular, the main structural components can’t be replaced. While they are checked, monitored and repaired, there are limits to this. The ISS was not designed to last forever.</p>
<p>It survives in a harsh environment, travelling at 27,500 kilometres per hour, with a day/night cycle every 90 minutes (the time it takes the ISS to orbit Earth). </p>
<p>The temperature differences experienced during each cycle put a small fatiguing load on the structure. Over a few years, this is not significant. But over the course of decades this can cause fatigue failures in the metal structure.</p>
<p>So there comes a time when the costs and risks of maintaining the ISS become too high, and this has been determined to be in 2030.</p>
<h2>How will the de-orbiting work?</h2>
<p>As with all objects under the influence of gravity, given time the ISS would simply fall down to Earth. This is because, even at the orbital altitude of 400km, there is some drag due to small particles. In fact, the ISS currently requires a regular boost to lift its orbital altitude, which is slowly – but constantly – decreasing.</p>
<p>A natural re-entry would be a completely uncontrolled process, and there would be no way of predicting where this would take place. The responsible (and planned) approach is to use thrusters to slow the ISS down, causing the de-orbit to happen much faster and in a specific location decided in advance.</p>
<p>The slowing down will initially be done using thrusters on the station, and on support vehicles docked to the station. This process may take a few months and will slowly reduce the orbital altitude of the ISS, preparing it for the final re-entry phase. </p>
<p>In the final phase, the deceleration will be much more rapid, and will determine the ISS’s final re-entry trajectory. Although it hasn’t been decided exactly how the ISS will reach its final deceleration, the favoured option is to use three modified Russian Progress spacecraft. </p>
<p>The spacecraft will be docked to the ISS and fire their propulsion systems to achieve the required deceleration – controlling the trajectory of the re-entry and the re-entry location.</p>
<h2>Artificial fireballs</h2>
<p>It will take a couple of minutes for the ISS to pass through the atmosphere. It’s likely the higher-altitude phase of this will take place near or above Australia.</p>
<p>The re-entry will be a visually spectacular event, resembling multiple large shooting stars. An increasing number of space debris breakup events have been observed and videoed over the last few years.</p>
<p>But these re-entries have been small objects, sized in the order of metres, such as the <a href="https://www.youtube.com/watch?v=OhBw5yaR_SU">ATV-1</a> and <a href="http://atv5.seti.org/cygnus/">Cygnus</a> spacecrafts. Meanwhile, the ISS is about the size of a football field, and will be correspondingly more spectacular.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/446194/original/file-20220214-13-89ti8u.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Space debris ablaze as it crashes down to Earth" src="https://images.theconversation.com/files/446194/original/file-20220214-13-89ti8u.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/446194/original/file-20220214-13-89ti8u.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=338&fit=crop&dpr=1 600w, https://images.theconversation.com/files/446194/original/file-20220214-13-89ti8u.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=338&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/446194/original/file-20220214-13-89ti8u.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=338&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/446194/original/file-20220214-13-89ti8u.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=425&fit=crop&dpr=1 754w, https://images.theconversation.com/files/446194/original/file-20220214-13-89ti8u.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=425&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/446194/original/file-20220214-13-89ti8u.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=425&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">The ISS will burn up into many smaller ‘fireballs’ as it passes through the atmosphere – creating a spectacular view.</span>
<span class="attribution"><span class="source">Shutterstock</span></span>
</figcaption>
</figure>
<h2>Crashing at Point Nemo</h2>
<p>Due to the danger of components reaching the surface, it will be important to make sure they fall where there is minimal risk to people or property. Even a controlled re-entry will potentially spread pieces of debris over an area of hundreds, if not thousands, of kilometres. </p>
<p>This is why the ISS re-entry (and most space debris de-orbits) will target an area known as the South Pacific Ocean Uninhabited Area (SPOUA), the centre of which is known as Point Nemo, or the “<a href="https://futurism.com/the-byte/deep-sea-graveyard-dead-spacecraft">Spacecraft Cemetery</a>” .</p>
<p>The SPOUA is used as Earth’s dumping ground for space debris. It’s the largest uninhabited area on Earth, and hence has the lowest risk associated with debris from re-entry.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/446198/original/file-20220214-55472-tbyu1a.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/446198/original/file-20220214-55472-tbyu1a.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/446198/original/file-20220214-55472-tbyu1a.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=545&fit=crop&dpr=1 600w, https://images.theconversation.com/files/446198/original/file-20220214-55472-tbyu1a.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=545&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/446198/original/file-20220214-55472-tbyu1a.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=545&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/446198/original/file-20220214-55472-tbyu1a.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=685&fit=crop&dpr=1 754w, https://images.theconversation.com/files/446198/original/file-20220214-55472-tbyu1a.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=685&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/446198/original/file-20220214-55472-tbyu1a.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=685&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Point Nemo, known as ‘the oceanic pole of inaccessibility’, is a point in the ocean which is the farthest away from any land.</span>
<span class="attribution"><a class="source" href="https://spaceplace.nasa.gov/spacecraft-graveyard/en/#">NASA</a></span>
</figcaption>
</figure>
<p>The ISS will be travelling at something like 6km per second when it hits the atmosphere. This high speed will cause the air in front of the structure to heat up significantly, reaching temperatures in excess of 10,000°C. </p>
<p>This will cause the structure to break into smaller pieces. Most of it will burn up as it falls, but it’s very likely some small pieces will survive – especially some of the heavier and denser internal components. </p>
<p>Any surviving debris will eventually sink into the ocean and disappear.</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/IR2aol0Bna4?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">The Cygnus spacecraft is an uncrewed cargo ship that brings supplies to the ISS and removes unwanted waste. For disposal, the spacecraft and waste burn up upon re-entry.</span></figcaption>
</figure><img src="https://counter.theconversation.com/content/176690/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Fabian Zander receives funding from the Australian Research Council. </span></em></p>How will they bring the structure back safely? And where will the surviving components crash?Fabian Zander, Senior Research Fellow in Aerospace Engineering, University of Southern QueenslandLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1721052021-11-18T20:58:38Z2021-11-18T20:58:38ZRussia’s attack on its own satellite is reckless and endangers us all<figure><img src="https://images.theconversation.com/files/432726/original/file-20211118-24-19gv0e0.jpg?ixlib=rb-1.1.0&rect=0%2C0%2C4089%2C2152&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Space debris produced by anti-satellite weapons can have dangerous consequences.</span> <span class="attribution"><span class="source">(Shutterstock)</span></span></figcaption></figure><p>Earlier this week, <a href="https://www.space.com/space-debris-astronauts-shelter-november-2021">astronauts onboard the International Space Station rushed to seek shelter</a>. The near-evacuation was not caused by <a href="https://earthsky.org/space/are-solar-storms-dangerous-to-us/">an unpredictable space weather event</a> or <a href="https://www.esa.int/Safety_Security/Space_Debris/Space_debris_by_the_numbers">the millions of pieces of remains of existing space objects and rocket launchers left there</a> since the beginning of the Space Age.</p>
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Read more:
<a href="https://theconversation.com/russian-anti-satellite-weapon-test-what-happened-and-what-are-the-risks-172016">Russian anti-satellite weapon test: What happened and what are the risks?</a>
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<p>The lives of astronauts were temporarily threatened by a cloud of orbital debris — space junk — <a href="https://www.bbc.com/news/science-environment-59299101">created by the testing of anti-satellite (ASAT) capabilities by Russia</a>.</p>
<p>What is not temporary is the threat that space debris will pose to the thousands of other functioning satellites that form the backbone of modern economies and societies. </p>
<p>Russia blew up one of its own defunct satellites, and in the process, created over 1,500 pieces of trackable debris that will remain in orbit well into the 2040s. It is not clear how many pieces of untraceable debris have been created.</p>
<p><div data-react-class="Tweet" data-react-props="{"tweetId":"1460369576277991428"}"></div></p>
<h2>Debris and condemnation</h2>
<p>For decades, <a href="https://swfound.org/counterspace/">major space-faring nations have tested a variety of weapons with the capabilitiy to destroy space objects</a> and launch attacks on Earth from space. The latest kinetic weapon test has created not just debris in space, but also sent shock waves around the world. </p>
<p>Stray and uncontrolled debris travels multiple times faster than a bullet, and can easily disable or even destroy the satellites that we depend on for <a href="https://www.unoosa.org/oosa/en/benefits-of-space/benefits.html">basic but critical activities</a>. Satellites facilitate banking transactions, land and ocean management, search and rescue operations and weather monitoring, among other things.</p>
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Read more:
<a href="https://theconversation.com/we-need-new-treaties-to-address-the-growing-problem-of-space-debris-115757">We need new treaties to address the growing problem of space debris</a>
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<p>Calling the action “reckless and irresponsible,” the United States issued a statement announcing that debris created by the latest weapons test in space will threaten “<a href="https://www.state.gov/russia-conducts-destructive-anti-satellite-missile-test/">space objects that are vital to all nations’ security, economic and scientific interests for decades to come</a>.” </p>
<p>The NATO secretary general also expressed that this “reckless act” will pose a threat to civilian activities and “<a href="https://www.nato.int/cps/en/natohq/opinions_188605.htm">important space capabilities for basic infrastructure on Earth like communications, like navigation, or like early warning of missile launches</a>.” </p>
<p>Condemnations of this single event were echoed in <a href="https://www.lemonde.fr/international/live/2021/11/17/du-tir-antisatellite-russe-a-la-guerre-spatiale-posez-vos-questions-a-nos-journalistes_6102432_3210.html">France</a>, the <a href="https://www.bbc.com/news/science-environment-59299101">United Kingdom</a> and <a href="https://www.daijiworld.com/news/newsDisplay?newsID=894629">South Korea</a>. </p>
<p><div data-react-class="Tweet" data-react-props="{"tweetId":"1460982576605237253"}"></div></p>
<p>Various space industry associations and businesses have expressed <a href="https://www.satellitetoday.com/government-military/2021/11/16/russia-confirms-asat-test-space-industry-condemns-deliberate-action/">concerns about Russia’s latest act</a>. These concerns are not only limited to the increased risk to multi-million dollar space assets, but also the cost that may be incurred in manoeuvring satellites to avoid possible collisions with the new debris created by the Russian ASAT.</p>
<p>A more upsetting possibility is that other countries may be encouraged to follow suit and conduct similar weapons tests in space, thereby exacerbating rising geopolitical tensions and accelerate an arms race in space. </p>
<h2>Space is not a vacuum</h2>
<p>Space activities are subject to extensive laws and regulations. In 1958, it was universally agreed that <a href="https://www.unoosa.org/pdf/gares/ARES_13_1348E.pdf">all nations have a “common interest” in outer space, and that space should be used for “peaceful purposes.”</a> </p>
<p>The 1967 Outer Space Treaty, one of the most widely accepted international instruments, obliges governments to conduct space activities “<a href="https://www.unoosa.org/oosa/en/ourwork/spacelaw/treaties/outerspacetreaty.html">for the benefit and in the interests of all countries</a>,” and with due regard to space activities of other nations. Though not expressly prohibited, destructive acts in space can have global impacts and are contrary to established principles of international law. </p>
<p>Despite the latest weapons test, there are ongoing initiatives to safeguard the safety, security and sustainability of outer space. For over three decades, the United Nations has <a href="https://digitallibrary.un.org/record/3895439?ln=en">annually called on nations to prevent an arms race in outer space</a>.</p>
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Read more:
<a href="https://theconversation.com/were-drafting-a-legal-guide-to-war-in-space-hopefully-well-never-need-to-use-it-86677">We're drafting a legal guide to war in space. Hopefully we'll never need to use it</a>
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<hr>
<p>Together with China, Russia itself has been an active supporter of a <a href="https://www.nti.org/education-center/treaties-and-regimes/proposed-prevention-arms-race-space-paros-treaty/">binding treaty to outlaw the use of force against space objects</a>. If this treaty had been adopted, it would have prohibited the very kind of act that was just undertaken.</p>
<p>Civil society initiatives to <a href="https://www.mcgill.ca/milamos/">clarify the law as it applies to military activities in outer space</a> are ongoing.</p>
<p>A letter — initiated by the Vancouver-based Outer Space Institute and signed by academics, policymakers and legal experts — addressed to the president of the UN General Assembly urged the adoption <a href="http://outerspaceinstitute.ca/docs/OSI_International_Open_Letter_ASATs_PUBLIC.pdf">of a treaty that would ban the testing of anti-satellite weapons</a>.</p>
<h2>Actions speak louder than words</h2>
<p>Space is widely recognized as being the “<a href="https://medium.com/s/story/space-is-the-ultimate-high-ground-thats-why-militaries-fund-astrophysics-67d7510c875">ultimate high ground</a>,” meaning that it holds significant strategic and military value. <a href="https://www.newscientist.com/article/2297849-anti-satellite-weapons-will-further-tests-make-space-more-dangerous/">The U.S., China and India</a>, major space-faring nations, have also tested a variety of ASAT weapons and capabilities to destroy their respective objects in space.</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/T0QXW17NqDg?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">Global News covers Russia’s weapon test.</span></figcaption>
</figure>
<p>Russia’s ASAT test is worrying as it may normalize unilateral actions in space that jeopardize the common interests of all countries. More worrying is the fact that this may not be the last action of its kind given the <a href="https://www.dw.com/en/russia-accuses-us-of-hypocrisy-over-satellite-destruction/a-59834986">disparity that often exists between the condemnations and actions undertaken by governments</a>. </p>
<p>However, space is also a shared global commons, which must be used in a responsible, safe and sustainable manner by all. Earlier this year, G7 leaders recognized that “<a href="https://www.gov.uk/government/news/g7-nations-commit-to-the-safe-and-sustainable-use-of-space">the orbit of our planet is a fragile and valuable environment that is becoming increasingly crowded” and that “all nations must act together” to safeguard it</a>. </p>
<p>It is imperative the international community unites to dissuade tensions in outer space, and urgently halt all reckless and irresponsible acts that will impact present and future generations.</p><img src="https://counter.theconversation.com/content/172105/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>The authors do not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and have disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Russia’s testing of an anti-satellite weapon risked the life of astronauts on the International Space Station and could have astronomical impacts on Earth.Kuan-Wei Chen, Executive Director, Centre for Research in Air and Space Law, McGill UniversityBayar Goswami, Arsenault Doctoral Fellow at the Institute of Air and Space Law, McGill UniversityRam S. Jakhu, Full Professor, Acting Director, Institute of Air and Space Law, McGill UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1720782021-11-17T14:54:48Z2021-11-17T14:54:48ZDestroyed Russian satellite creates yet more space debris to threaten the International Space Station<figure><img src="https://images.theconversation.com/files/432401/original/file-20211117-27-yregr2.jpg?ixlib=rb-1.1.0&rect=0%2C10%2C3508%2C2441&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Artist's view of traceable debris around the Earth - the debris is shown magnified relative to the size of the Earth.</span> <span class="attribution"><span class="source">ESA</span>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span></figcaption></figure><p>On Monday 15 November, Russia <a href="https://edition.cnn.com/2021/11/15/politics/russia-anti-satellite-weapon-test-scn/index.html">destroyed</a> one of its old satellites in an anti-satellite missile test.</p>
<p>The impact created a cloud of space debris in an area of space through which the International Space Station regularly passes, and members of the ISS were forced to seek safety in their spacecraft in the immediate aftermath of the test.</p>
<p>The US 18th Space Control Squadron confirmed the breakup of the COSMOS-1408 satellite on November 16. It estimates that there could be around 1,500 new pieces of debris floating through space as a result of the incident.</p>
<p><div data-react-class="Tweet" data-react-props="{"tweetId":"1460388384078139399"}"></div></p>
<p>There is a vast amount of debris circulating in Earth’s orbit: it is one of the inherent consequences of human activity in space.</p>
<p>The first debris arrived in 1957 with the launch of Sputnik-1. More than 5,000 launches have taken place since then – generating 23,200 catalogued objects larger than 10 centimetres across, which represent 99% of the total mass in orbit, more than 8,000 tonnes.</p>
<p>The launches have also generated about 740,000 objects between 1 and 10 centimetres in size, as well as more than 160,000 objects between 0.1 and 1 centimetres.</p>
<p>In recent years, new satellite constellations launched by private companies have put more objects into orbit than the country of France has in its entire history.</p>
<h2>The dangers of space debris</h2>
<p>In Earth’s orbit, there are operational satellites, end-of-life satellites, abandoned launch vehicle stages and fragments of all sizes, mainly from accidental or deliberate explosions or the ageing of materials in space.</p>
<p>Objects in low orbit (an altitude of less than 2,000km) travel at very high velocity. At eight kilometres per second, a piece of debris can inflict significant damage on an operational satellite in the event of a collision.</p>
<iframe src="https://cdn.knightlab.com/libs/timeline3/latest/embed/index.html?source=1A-0syAm8IJnFcSG_gFJ7lfR3IvnVRC0AIm17ewE-od4&font=Default&lang=en&initial_zoom=2&height=650" width="100%" height="650" webkitallowfullscreen="" mozallowfullscreen="" allowfullscreen="" frameborder="0"></iframe>
<p>Two major events have generated a significant amount of the space debris currently in orbit. In 2007, China deliberately destroyed one its own satellites in an <a href="https://www.cfr.org/backgrounder/chinas-anti-satellite-test">anti-missile weapon test</a>, with 3,527 pieces of identified debris still in orbit in March 2021. Then, in 2009, the <a href="https://link.springer.com/chapter/10.1007/978-3-7091-0318-0_10">the American satellite Iridium 33 and the Russian satellite Cosmos 2251</a> collided in orbit. This event alone doubled the amount of debris over 10 centimetres currently circulating.</p>
<p>Some of the pieces of unidentified debris (those smaller than 10 centimetres) came down and burned up on re-entering the atmosphere. Despite this, there are probably still a number that cannot be seen because they are too small but which nevertheless pose a danger to operational satellites.</p>
<p>Space debris can also pose a risk on the ground if large fragments fall back to Earth. Statistically, one large piece of debris falls to the Earth’s surface every week (mostly into the sea). </p>
<p>To date there have been no fatalities caused by falling space debris. One person was reportedly hit on the shoulder <a href="https://www.wired.com/2009/01/jan-22-1997-heads-up-lottie-its-space-junk/">in the United States</a> in 1997, and a piece of debris over 10 metres long from a Chinese rocket <a href="https://www.theverge.com/2020/5/13/21256484/china-rocket-debris-africa-uncontrolled-reentry-long-march-5b">fell to Earth in Cote d’Ivoire</a> in 2020.</p>
<h2>Monitoring debris</h2>
<p>In order to combat the proliferation of dangerous debris, a number of agencies voluntarily monitor Earth’s orbit.</p>
<p>The French National Centre for Space Studies, where I work, uses data from the 18th Space Control Squadron, to which we add <a href="https://www.onera.fr/en/news/graves-the-1st-european-space-surveillance-system">data from the European GRAVES Space Surveillance System</a> that detects debris in low orbit – between 400km and 1,000km in altitude. These observations are supplemented by military radars and data from the air force.</p>
<p>For geostationary orbit – the zone 36,000km from the equator – US military information is supplemented by observations from telescopes like those in the <a href="https://grandma.ijclab.in2p3.fr/observatories/tarot/">TAROT network</a>. Image processing allows us to detect objects and calculate their trajectories. The accuracy of this trajectory is improved with each new observation, which makes it possible to assess the risk of collision.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/387237/original/file-20210302-19-1bjmk3i.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/387237/original/file-20210302-19-1bjmk3i.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=399&fit=crop&dpr=1 600w, https://images.theconversation.com/files/387237/original/file-20210302-19-1bjmk3i.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=399&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/387237/original/file-20210302-19-1bjmk3i.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=399&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/387237/original/file-20210302-19-1bjmk3i.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=502&fit=crop&dpr=1 754w, https://images.theconversation.com/files/387237/original/file-20210302-19-1bjmk3i.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=502&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/387237/original/file-20210302-19-1bjmk3i.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=502&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">One of the telescopes in the TAROT network at La Silla in Chile.</span>
<span class="attribution"><a class="source" href="http://www.eso.org/public/france/images/klotz-3/">ESO</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
</figcaption>
</figure>
<p>Unfortunately, it is only possible to intervene on space objects that have their own propulsion system. Based on radar measurements, trajectories are propagated over time and the risk of collision is assessed.</p>
<h2>The clean-up</h2>
<p>As well as avoiding collisions, there is also work underway on a number of technologies that will eventually enable us to remove debris from space.</p>
<p>Last December, the European Space Agency <a href="https://www.francebleu.fr/infos/sante-sciences/depollution-de-l-espace-l-agence-spatiale-europeenne-lance-une-mission-inedite-de-ramassage-de-1606831160">signed a contract with the Swiss start-up Clear Space</a> to carry out the first space debris removal mission. And in March, Astroscale, a private Singaporean company <a href="https://astroscale.com/elsa-d-spacecraft-arrives-for-march-launch/">launched ELSA-d</a>, a demonstration mission to clean up debris in orbit.</p>
<p>Still, prevention is the best approach to avoid large amounts of space debris accumulating. The United Nations has set out <a href="https://www.unoosa.org/pdf/publications/st_space_49E.pdf">anti-proliferation rules</a>, which are simple:</p>
<ul>
<li><p>Do not produce debris in orbit intentionally</p></li>
<li><p>Remove all energy sources from satellites at the end of their life (by <a href="https://www.esa.int/Safety_Security/Clean_Space/Sending_a_satellite_safely_to_sleep">jettisoning the fuel</a> that could generate other debris by exploding during a collision)</p></li>
<li><p>Respect the “25-year rule” for satellites in low-earth orbit, which states that satellites must re-enter the atmosphere within 25 years of the end of their operational life</p></li>
<li><p>Respect the “graveyard orbit” for geostationary satellites (an orbit path that avoids operational satellites).</p></li>
</ul>
<p>These rules make it possible to begin to control the increase in debris, but they are applied progressively and with the diligence of each state. There are many satellites or launch vehicle stages of older generations in space that do not comply with these rules and remain a cause for concern.</p>
<p>As this latest incident shows, the need for regulation is becoming increasingly important. This is especially the case with the advent satellite megaconstellations and the proliferation of <a href="https://theconversation.com/les-cubesats-un-exemple-dinnovation-low-cost-dans-lindustrie-spatiale-129375">low-cost nanosatellites</a>.</p><img src="https://counter.theconversation.com/content/172078/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Pierre Omaly ne travaille pas, ne conseille pas, ne possède pas de parts, ne reçoit pas de fonds d'une organisation qui pourrait tirer profit de cet article, et n'a déclaré aucune autre affiliation que son organisme de recherche.</span></em></p>A Russian satellite has been destroyed in a missile strike, creating a vast amount of debris that joins the tens of thousands of pieces already in orbit around the Earth.Pierre Omaly, Expert débris spatiaux et responsable de l’initiative Tech 4 Space Care, Centre national d’études spatiales (CNES)Licensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1720162021-11-16T23:58:54Z2021-11-16T23:58:54ZRussian anti-satellite weapon test: What happened and what are the risks?<figure><img src="https://images.theconversation.com/files/432281/original/file-20211116-25-1uty5z7.jpg?ixlib=rb-1.1.0&rect=120%2C0%2C1796%2C948&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">If a satellite is destroyed, the debris fans out in orbit and poses serious threats to other satellites or crewed spacecraft. </span> <span class="attribution"><a class="source" href="https://commons.wikimedia.org/wiki/File:Satellite_break-up_ESA375611.tiff#/media/File:Satellite_break-up_ESA375611.tiff">ESA/ID&Sense/ONiRiXEL via WikimediaCommons</a>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span></figcaption></figure><p><em>On Nov. 15, 2021, U.S. officials announced that they had detected a dangerous new debris field in orbit near Earth. Later in the day, it was confirmed that Russia had destroyed one of its old satellites in a test of an anti-satellite weapon. <a href="https://scholar.google.com/citations?hl=en&user=PxIOz7cAAAAJ">Wendy Whitman Cobb is a space security researcher</a>. She explains what these weapons are and why the debris they create is a problem now – and in the future.</em></p>
<h2>What do we know?</h2>
<p><a href="https://www.spacecom.mil/News/Article-Display/Article/2842957/russian-direct-ascent-anti-satellite-missile-test-creates-significant-long-last/">Russia launched an anti-satellite test</a> that destroyed one of its older satellites. The satellite broke up and created thousands of pieces of debris in orbit, ranging in size from tiny specks up to pieces a few feet across. This space junk will linger in orbit for years, potentially colliding with other satellites as well as the International Space Station. The <a href="https://www.nasa.gov/press-release/nasa-administrator-statement-on-russian-asat-test/">space station crew has already had to shelter</a> in place as they passed near the debris cloud.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/432283/original/file-20211116-19-enwd7i.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A long white and red missile on display." src="https://images.theconversation.com/files/432283/original/file-20211116-19-enwd7i.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/432283/original/file-20211116-19-enwd7i.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=278&fit=crop&dpr=1 600w, https://images.theconversation.com/files/432283/original/file-20211116-19-enwd7i.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=278&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/432283/original/file-20211116-19-enwd7i.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=278&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/432283/original/file-20211116-19-enwd7i.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=349&fit=crop&dpr=1 754w, https://images.theconversation.com/files/432283/original/file-20211116-19-enwd7i.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=349&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/432283/original/file-20211116-19-enwd7i.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=349&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Many anti-satellite weapons are missiles launched from the ground, like this U.S. ASM-135 ASAT.</span>
<span class="attribution"><a class="source" href="https://commons.wikimedia.org/wiki/File:Asat_missile_20040710_150339_1.4.jpg#/media/File:Asat_missile_20040710_150339_1.4.jpg">Lorax via WikimediaCommons</a>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span>
</figcaption>
</figure>
<h2>What’s an anti-satellite weapon?</h2>
<p><a href="https://csis-website-prod.s3.amazonaws.com/s3fs-public/publication/210331_Harrison_SpaceThreatAssessment2021.pdf?gVYhCn79enGCOZtcQnA6MLkeKlcwqqks">Anti-satellite weapons</a>, commonly referred to as ASATs, are any weapon that can temporarily impair or permanently destroy an orbiting satellite. The one that Russia just tested is known as a <a href="https://www.spacecom.mil/News/Article-Display/Article/2842957/russian-direct-ascent-anti-satellite-missile-test-creates-significant-long-last/">direct ascent kinetic anti-satellite weapon</a>. These are usually launched from the ground or from the wings of an airplane and destroy satellites by running into them at high speeds.</p>
<p>A similar weapon type, called <a href="https://aerospace.csis.org/aerospace101/counterspace-weapons-101/">co-orbital anti-satellite weapons</a>, are first launched into orbit and then change direction to collide with the targeted satellite from space. </p>
<p>A third type, <a href="https://aerospace.csis.org/aerospace101/counterspace-weapons-101/">non-kinetic anti-satellite weapons</a>, use technology like lasers to disrupt satellites without physically colliding with them.</p>
<p>Space agencies have been <a href="https://swfound.org/counterspace/">developing and testing anti-satellite weapons</a> since the 1960s. To date, the <a href="https://www.thespacereview.com/article/4198/1">U.S.</a>, <a href="https://www.spacecom.mil/MEDIA/NEWS-ARTICLES/Article/2285098/russia-conducts-space-based-anti-satellite-weapons-test/">Russia</a>, <a href="https://swfound.org/media/9550/chinese_asat_fact_sheet_updated_2012.pdf">China</a> and <a href="https://www.armscontrol.org/act/2019-05/news/indian-asat-test-raises-space-risks">India</a> have demonstrated the ability to attack satellites in orbit that support services like GPS, communications and weather forecasting.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/432284/original/file-20211116-23-1bg1lxk.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="An image of the Earth with many red lines surrounding it." src="https://images.theconversation.com/files/432284/original/file-20211116-23-1bg1lxk.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/432284/original/file-20211116-23-1bg1lxk.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=409&fit=crop&dpr=1 600w, https://images.theconversation.com/files/432284/original/file-20211116-23-1bg1lxk.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=409&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/432284/original/file-20211116-23-1bg1lxk.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=409&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/432284/original/file-20211116-23-1bg1lxk.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=514&fit=crop&dpr=1 754w, https://images.theconversation.com/files/432284/original/file-20211116-23-1bg1lxk.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=514&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/432284/original/file-20211116-23-1bg1lxk.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=514&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Debris from a single destroyed satellite can spread out rapidly, as seen in this image showing the orbits of debris from a Chinese satellite one month after it was destroyed in 2007.</span>
<span class="attribution"><a class="source" href="https://commons.wikimedia.org/wiki/File:Fengyun-1C_debris.jpg">NASA Orbital Debris Program Office via WikimediaCommons</a></span>
</figcaption>
</figure>
<h2>Why is debris a problem?</h2>
<p>Regardless of the cause, space debris is a serious problem. </p>
<p>Larger pieces are easier to track and avoid but it’s difficult to track pieces smaller than 4 inches (10 centimeters). Even small debris can still pose a major threat though. Space debris <a href="https://www.nasa.gov/mission_pages/station/news/orbital_debris.html">is often traveling faster than 17,000 mph</a> around the Earth. At that speed, pieces of debris could destroy any spacecraft or satellite it collided with. In the 1980s, <a href="https://www.thespacereview.com/article/2520/1">a Soviet satellite broke up</a> as a result of a suspected debris strike. </p>
<p>More worrisome is the danger debris poses to crewed space missions. In July 2021, one of the International Space Station’s <a href="https://www.nbcnews.com/science/space/space-junk-damages-international-space-stations-robotic-arm-rcna1067">robotic arms was struck</a> by a piece of debris that put a 0.2-inch (0.5 cm) hole clean through a part of the arm. While the damage did not need to be fixed, officials characterized it as a lucky strike – if it had struck a different part of the station, the situation could have been a lot worse.</p>
<p>Space debris is also a significant threat to people on Earth. Satellites play a vital role in the global economy through GPS, communications and weather data. If services such as these were disrupted, there would be <a href="https://www.routledge.com/Privatizing-Peace-How-Commerce-Can-Reduce-Conflict-in-Space/Cobb/p/book/9780367337834">significant economic cost</a>. One study found that a GPS outage could <a href="https://www.space.commerce.gov/doc-study-on-economic-benefits-of-gps/">cost the U.S. up to $1 billion a day</a>.</p>
<p>There are currently <a href="https://www.nasa.gov/mission_pages/station/news/orbital_debris.html">thousands of pieces of space junk</a> circling the Earth, with sources as varied as old rocket bodies, dead satellites, debris from previous collisions and tests, and lost items from astronauts. The problem – like with the environment – is that there is <a href="https://theconversation.com/if-a-satellite-falls-on-your-house-space-law-protects-you-but-there-are-no-legal-penalties-for-leaving-junk-in-orbit-160757">little incentive for individual countries</a> to avoid generating debris or clean it up.</p>
<p>The amount of space debris has only increased over time. For years, scientists have been warning about the possibility of a collision cascade. <a href="https://www.space.com/kessler-syndrome-space-debris">As the amount of debris increases</a>, the chance of collisions between it and other satellites and debris also goes up. More collisions might then leave certain orbits completely unusable. While this could take decades to play out, events like the Russian test will only make such an outcome more likely.</p>
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<h2>What to do now?</h2>
<p>In the short term, little can be done to mitigate this new cloud of space debris, but anyone with anything in space is on high alert to avoid it.</p>
<p>The U.S. government and commercial companies are tracking the new debris, and the crew on the International Space Station have been <a href="https://www.cbsnews.com/news/satellite-debris-space-station-crew-take-shelter/">ordered to keep certain modules closed off</a> as they continue to pass through the debris cloud. As the new debris spreads out and the pieces are tracked, station controllers will have a better understanding of the danger posed to the crew.</p>
<p>In the long run, <a href="https://www.esa.int/Safety_Security/Space_Debris/Global_experts_agree_action_needed_on_space_debris">experts recommend</a> working on global solutions to remove debris. This includes taking measures to prevent debris in the first place and removing debris that is already in space. Several governmental and international organizations have <a href="https://spacenews.com/u-s-interagency-panel-to-update-rd-strategy-to-tackle-orbital-debris/">proposed ways to prevent new debris</a>, but these are informal and not legally binding.</p>
<p>Remediation is a tougher challenge. Technology to remove debris has not yet been fully developed, but even still, its <a href="https://swfound.org/news/all-news/2019/07/analysis-of-the-potential-misuse-of-commercial-dual-use-technologies-for-satellite-servicing/">deployment is a sensitive subject</a>. The same technology that might be used to remove a piece of space junk could also be used for attacking a satellite. This dual-use technology poses challenges, as it can raise suspicions that <a href="https://www.space.com/china-launches-military-space-junk-satellite">countries are testing</a> anti-satellite weapons under the cover of debris removal. </p>
<p>Despite the difficulties, there is growing international recognition that space debris is a dangerous problem. A consortium of private companies recently created the <a href="https://spacenews.com/space-companies-forge-alliance-to-reduce-in-orbit-debris-by-2030/">Net Zero Space charter</a> to reduce debris, and the <a href="https://spacenews.com/space-force-launches-orbital-prime-program-to-spur-market-for-on-orbit-services/">U.S. Space Force is looking for ways</a> to combat the problem as well. While the world still does not yet have a full understanding of Russia’s actions, this event is a wake-up call on the importance of efforts to reduce pollution in Earth’s orbit.</p><img src="https://counter.theconversation.com/content/172016/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Wendy Whitman Cobb is affiliated with the US Air Force School of Advanced Air and Space Studies. Her views are her own and do not necessarily reflect the views of the Department of Defense or any of its components.</span></em></p>Russia destroyed one of its old satellites during a successful test of an anti-satellite weapon. A space security expert explains what this weapon was and the dangers of the expanding debris field.Wendy Whitman Cobb, Professor of Strategy and Security Studies, Air UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1649402021-07-23T05:22:15Z2021-07-23T05:22:15ZKeen to sign up for space tourism? Here are 6 things to consider (besides the price tag)<figure><img src="https://images.theconversation.com/files/412834/original/file-20210723-23-10ujqv0.jpg?ixlib=rb-1.1.0&rect=0%2C5%2C2000%2C1104&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><span class="source">Blue Origin/AP</span></span></figcaption></figure><p>It’s been a momentous month for space-faring billionaires. On July 11, British entrepreneur Sir Richard Branson’s Unity “rocket-plane” <a href="https://www.bbc.com/news/science-environment-57797297">flew him and five fellow passengers</a> about 85 kilometres above Earth. And this week, Amazon founder Jeff Bezos’ New Shepard capsule <a href="https://www.abc.net.au/news/2021-07-20/jeff-bezos-soars-into-space-on-blue-origins-new-shepard-rocket/100304412">reached an altitude of 106km</a>, carrying Bezos, his brother, and the <a href="https://www.universetoday.com/151900/blue-origin-successfully-launches-the-oldest-and-youngest-person-to-ever-go-to-space-oh-and-jeff-bezos-too/">oldest and youngest people</a> ever to reach such a height. Passengers on both flights experienced several minutes of weightlessness and took in breathtaking views of our beautiful and fragile Earth. </p>
<p>Both flights created an avalanche of media coverage and brand recognition for Branson’s Virgin Galactic and Bezos’s Blue Origin. There is renewed anticipation of a lucrative commercial space tourism industry that could eventually see thousands of paying passengers journey into space (or not quite into space, depending on your preferred level of pedantry).</p>
<p>This year marks 60 years since Soviet cosmonaut Yuri Gagarin became the first human in space. Since then, <a href="https://en.wikipedia.org/wiki/List_of_space_travelers_by_nationality">almost 600 trained astronauts</a> have gone into outer space, but very few people have become space tourists. </p>
<p>The first, US engineer Dennis Tito, paid a reported US$20 million to spend six days orbiting Earth in the Russian section of the International Space Station in April 2001, after three months’ training at Russia’s Star City complex. He was followed by a handful of other very wealthy “orbital tourists”, most recently Cirque de Soleil founder Guy Laliberté in 2009, whose ticket reportedly cost US$35 million.</p>
<p>Unlike their predecessors, Branson’s and Bezos’ flights were suborbital – they didn’t reach the velocity needed to orbit Earth. Bezos’s entire flight lasted just over 10 minutes. Suborbital flights are much less technically complex, and in theory cheaper (although one seat on the New Shepard flight was <a href="https://www.cnbc.com/2021/07/15/blue-origin-reveals-oliver-daemen-flying-to-space-with-jeff-bezos.html">auctioned for US$28 million</a>).</p>
<figure class="align-center ">
<img alt="Interior of Blue Origin capsule" src="https://images.theconversation.com/files/412835/original/file-20210723-19-12y56wo.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/412835/original/file-20210723-19-12y56wo.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/412835/original/file-20210723-19-12y56wo.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/412835/original/file-20210723-19-12y56wo.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/412835/original/file-20210723-19-12y56wo.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/412835/original/file-20210723-19-12y56wo.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/412835/original/file-20210723-19-12y56wo.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
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<span class="caption">You expect a luxurious interior when you pay this much.</span>
<span class="attribution"><span class="source">Michael Craft/Blue Origin/AP</span></span>
</figcaption>
</figure>
<p>While they might quibble over billionaire bragging rights, there’s no denying that suborbital “space” flights have the potential to be less eye-wateringly expensive than going into orbital outer space and beyond.</p>
<p>But before you sign up – assuming you’re lucky enough to afford it – here are a few things to consider. </p>
<h2>Where does space start, anyway?</h2>
<p>Despite <a href="https://www.cnbc.com/2021/07/09/where-space-begins-bezos-blue-origin-vs-bransons-virgin-galactic.html">assertions to the contrary</a>, there is no legal definition of “outer space”, and thus no official boundary where airspace ends and outer space begins. In the past, the International Aeronautical Federation has looked to the <a href="https://www.fai.org/page/icare-boundary">von Karman line</a>, but this does not coincide with the boundary of any of the atmosphere’s scientifically defined layers, and the <a href="https://www.unoosa.org/oosa/en/ourwork/copuos/index.html">UN Committee on the Peaceful Uses of Outer Space</a>, which deals with such issues, has not yet resolved the question. </p>
<p>Conveniently for Branson, 80km has been <a href="https://arxiv.org/abs/1807.07894">proposed</a> by some experts as an appropriate boundary. </p>
<p>Outer space is undeniably influenced by Earthly geopolitics. Essentially, the larger space-faring countries see no need to legally define a boundary that would clearly demarcate the upper limits of their sovereignty.</p>
<h2>Will you be an ‘astronaut’?</h2>
<p>The <a href="https://www.unoosa.org/oosa/en/ourwork/spacelaw/treaties/outerspacetreaty.html">1967 UN Outer Space Treaty</a> designates astronauts as “envoys of (hu)mankind in outer space”. Certainly, that seemed to be the case as the world watched the historic Apollo 11 Moon landing and prayed for a safe return of the stricken Apollo 13 capsule. However, the <a href="https://www.unoosa.org/pdf/gares/ARES_22_2345E.pdf">1968 UN Rescue Agreement</a> refers to “personnel of a spacecraft”, which may imply not everyone on board should be considered a fully fledged astronaut.</p>
<p>Of course, these legal niceties won’t deter space tourism companies from awarding “astronaut wings” to their passengers.</p>
<h2>What laws apply when things go wrong?</h2>
<p>The <a href="https://www.space.com/31760-space-shuttle-challenger-disaster-30-years.html">1986 Challenger</a> and <a href="https://www.space.com/19436-columbia-disaster.html">2003 Columbia</a> shuttle disasters are stark reminders of the dangers of space travel. Human space travel has always involved determining acceptable levels of risk for trained astronauts. But commercial space tourism is different to state-sponsored space programs, and will need the highest possible safety standards. </p>
<p>Commercial space travel will also require a system of responsibility and liability, for cases in which a space tourist suffers injury, loss or damage. </p>
<p>Space tourists (or their families) can’t claim for compensation under the <a href="https://www.unoosa.org/pdf/gares/ARES_26_2777E.pdf">1972 UN Liability Convention</a> which, in terms of space, applies only to collisions between space objects such as satellites and space debris. While there may be scope to take legal action under national laws, it is likely space tourists will be asked to sign carefully worded waivers of liability.</p>
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<em>
<strong>
Read more:
<a href="https://theconversation.com/want-to-become-a-space-tourist-you-finally-can-if-you-have-250-000-and-a-will-to-sign-your-life-away-160543">Want to become a space tourist? You finally can — if you have $250,000 and a will to sign your life away</a>
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<p>The same is probably true of <a href="https://www.iata.org/contentassets/fb1137ff561a4819a2d38f3db7308758/mc99-full-text.pdf">international air law</a>, which applies to “aircraft” — a designation space tourism operators will understandably be keen to avoid. </p>
<p>Ultimately, we may need to develop a system of “aerospace law” to govern these suborbital flights as well as “transorbital” transport such as the <a href="https://www.news.com.au/travel/travel-advice/flights/uk-to-australia-in-just-four-hours-with-6437kph-passenger-jet-set-to-launch-by-2030/news-story/021b1a480d63958711e50b60ededfaa8">keenly envisaged</a> flights that might one day take passengers from Sydney to London in just a few hours.</p>
<h2>What activities should be allowed in space?</h2>
<p>The advent of space tourism will give rise to some interesting ethical questions. Should there be advertising billboards in space? What about casinos, or brothels? On what legal basis should these things be restricted?</p>
<p>How does tourism fit with the underlying philosophy of space law: that the exploration and use of outer space “shall be carried out for the benefit and in the interests of all countries”?</p>
<h2>Will space tourism harm the environment?</h2>
<p>Space tourism will inevitably put pressure on Earth’s environment – there are <a href="https://www.theguardian.com/science/2021/jul/19/billionaires-space-tourism-environment-emissions">claims</a> that space vehicles may one day become the world’s biggest source of carbon dioxide emissions. We will need to manage space traffic carefully to avoid disastrous collisions and steer clear of <a href="http://ilareporter.org.au/2021/07/space-debris-a-major-challenge-for-the-future-of-humanity-steven-freeland/">space debris</a>. </p>
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<em>
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Read more:
<a href="https://theconversation.com/its-not-how-big-your-laser-is-its-how-you-use-it-space-law-is-an-important-part-of-the-fight-against-space-debris-158790">It's not how big your laser is, it's how you use it: space law is an important part of the fight against space debris</a>
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<p>If tourists go to the Moon, they may cause pollution or damage the heritage of earlier exploration, such as <a href="https://www.nytimes.com/2019/07/11/science/moon-apollo-11-archaeology-preservation.html">Neil Armstrong’s footprints</a>.</p>
<figure class="align-center ">
<img alt="Neil Armstrong's lunar footprint" src="https://images.theconversation.com/files/412826/original/file-20210723-17-1txet4l.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/412826/original/file-20210723-17-1txet4l.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=483&fit=crop&dpr=1 600w, https://images.theconversation.com/files/412826/original/file-20210723-17-1txet4l.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=483&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/412826/original/file-20210723-17-1txet4l.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=483&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/412826/original/file-20210723-17-1txet4l.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=607&fit=crop&dpr=1 754w, https://images.theconversation.com/files/412826/original/file-20210723-17-1txet4l.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=607&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/412826/original/file-20210723-17-1txet4l.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=607&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
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<span class="caption">Do not disturb.</span>
<span class="attribution"><span class="source">NASA</span></span>
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</figure>
<h2>Will tourism workers have to live in space?</h2>
<p>If space tourism does become truly widespread, it will need infrastructure and perhaps even staff. People may end up living permanently in space settlements, perhaps having children who will be born as “space citizens”. What legal rights would someone have if they were born at a Moon base? Would they be subject to terrestrial laws, or some version of current international legal rules for outer space?</p>
<p>These are obviously questions for the future. But given the excitement generated by the brief journeys of a couple of wealthy entrepreneurs, we should start contemplating them now. Outer space is the new frontier, but it is not — and must not — be a lawless one.</p><img src="https://counter.theconversation.com/content/164940/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Steven Freeland is a Director of the International Institute of Space Law</span></em></p>Sure, they’re billionaires, but the exploits of Richard Branson and Jeff Bezos have undeniably brought space tourism a step closer. That raises tricky legal, ethical and environmental questions.Steven Freeland, Professorial Fellow, Bond University / Emeritus Professor of International Law, Western Sydney University, Western Sydney UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1607572021-05-17T12:25:43Z2021-05-17T12:25:43ZIf a satellite falls on your house, space law protects you – but there are no legal penalties for leaving junk in orbit<figure><img src="https://images.theconversation.com/files/400832/original/file-20210514-13-1mq0r5w.jpg?ixlib=rb-1.1.0&rect=0%2C17%2C6000%2C3664&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">It's unlikely falling space junk will destroy property or kill a person. </span> <span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/satellite-royalty-free-image/476204650?adppopup=true">Petrovich9/iStock via Getty Images</a></span></figcaption></figure><p>On May 8, 2021, a piece of space junk from a Chinese rocket fell uncontrolled back to Earth and <a href="https://www.nytimes.com/2021/05/08/science/china-rocket-reentry-falling-long-march-5b.html">landed in the Indian Ocean near the Maldives</a>. A year ago, in May 2020, another Chinese rocket met the same fate when it plummeted out of control into the waters <a href="https://www.theverge.com/2020/5/13/21256484/china-rocket-debris-africa-uncontrolled-reentry-long-march-5b">off the West African coast</a>. No one knew when or where either of these pieces of space junk were going to hit, so it was a relief when neither crashed on land or injured anyone.</p>
<p>Space debris is any nonfunctional human-made object in space.
As a professor of <a href="https://sfis.asu.edu/timiebi-aganaba-jeanty">space and society focused on space governance</a>, I’ve noticed that there are three questions the public always asks when falling space debris gets into the news. Could this have been prevented? What would have happened if there was damage? And how will new commercial companies be regulated as space activities and launches <a href="https://www.euroconsult-ec.com/research/WS319_free_extract_2019.pdf">increase exponentially</a>?</p>
<p>For space law to be effective, it <a href="https://unoosa.org/pdf/pres/stsc2011/tech-35.pdf">needs to do three things</a>. First, regulation must prevent as many dangerous situations from occurring as possible. Second, there needs to be a way to monitor and enforce compliance. And finally, laws need to lay out a framework for responsibility and liability if things do go wrong. So, how do current laws and treaties around space stack up? They do OK, but interestingly, looking at environmental law here on Earth may give some ideas on how to improve the current legal regime with respect to space debris.</p>
<h2>What if a rocket landed on your house?</h2>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/400833/original/file-20210514-15-8pfz57.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A large white rocket on a launch pad." src="https://images.theconversation.com/files/400833/original/file-20210514-15-8pfz57.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/400833/original/file-20210514-15-8pfz57.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=1067&fit=crop&dpr=1 600w, https://images.theconversation.com/files/400833/original/file-20210514-15-8pfz57.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=1067&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/400833/original/file-20210514-15-8pfz57.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=1067&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/400833/original/file-20210514-15-8pfz57.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1340&fit=crop&dpr=1 754w, https://images.theconversation.com/files/400833/original/file-20210514-15-8pfz57.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1340&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/400833/original/file-20210514-15-8pfz57.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1340&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
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<span class="caption">Two Chinese Long March 5b rockets, like the one seen here, have crashed into the ocean within the past year.</span>
<span class="attribution"><a class="source" href="https://commons.wikimedia.org/wiki/File:%E9%95%BF%E5%BE%81%E4%BA%94%E5%8F%B7%E9%81%A5%E4%BA%8C%E7%81%AB%E7%AE%AD%E8%BD%AC%E5%9C%BA.jpg#/media/File:%E9%95%BF%E5%BE%81%E4%BA%94%E5%8F%B7%E9%81%A5%E4%BA%8C%E7%81%AB%E7%AE%AD%E8%BD%AC%E5%9C%BA.jpg">篁竹水声/WikimediaCommons</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
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</figure>
<p>Imagine that, instead of landing in the ocean, the recent Chinese rocket crashed into your house while you were at work. What would current law allow you to do?</p>
<p>According to the <a href="https://www.unoosa.org/oosa/en/ourwork/spacelaw/treaties/introouterspacetreaty.html">1967 Outer Space Treaty</a> and <a href="https://www.unoosa.org/oosa/en/ourwork/spacelaw/treaties/introliability-convention.html">1972 Liability Convention</a> – both adopted by the United Nations – this would be a government-to-government issue. The treaties declare that states are internationally responsible and liable for any damage caused by a spacecraft – even if the damage was caused by a private company from that state. According to these laws, your country wouldn’t even need to prove that someone had done something wrong if a space object or its component parts caused damage on the surface of the Earth or to normal aircraft in flight. </p>
<p>Basically, if a piece of space junk from China landed on your house, your own country’s government would make a claim for compensation through diplomatic channels and then pay you – if they chose to make the claim at all.</p>
<p>While the chances are slim to none that a broken satellite will land on your house, space debris has crashed onto land. In 1978, the Soviet Cosmos 954 satellite <a href="https://nationalinterest.org/feature/operation-morning-light-the-nuclear-satellite-almost-14411?page=1">fell into a barren region of Canada’s Northwest Territories</a>. When it crashed, it spread radioactive debris from its onboard nuclear reactor over a wide swath of land. A joint Canadian-American team began a cleanup effort that cost over CAD$14 million (US$11.5 million). The Canadians requested CAD$6 million from the Soviet Union, but the Soviets paid only CAD$3 million in the final settlement.</p>
<p>This was the first – and only – time the Liability Convention has been used when a spacecraft from one country has crashed in another. When the Liability Convention was put into use in this context, <a href="https://digitalcommons.law.yale.edu/cgi/viewcontent.cgi?article=1316&context=yjil">four governing norms emerged</a>. Countries have a duty to: warn other governments about debris; provide any information they could about an impending crash; clean up any damage caused by the craft; and compensate your government for any injuries that might have resulted.</p>
<p>There have been other instances where <a href="https://www.space.com/13049-6-biggest-spacecraft-falls-space.html">space junk has crashed back to Earth</a> – most notably when <a href="https://www.abc.net.au/news/2019-07-12/four-decades-on-from-skylabs-descent-from-space/11249626">Skylab, a U.S. space station, fell and broke up</a> over the Indian Ocean and uninhabited parts of Western Australia in 1979. A local government jokingly fined NASA AUS$400 (US$311) for littering – a fine that NASA ignored, though it was eventually <a href="https://www.skymania.com/wp/nasas-litter-bill-paid-30-years-on/">paid by an American radio host in 2009</a>. But despite this and other incidences, Canada remains the only country to put the Liability Convention to use.</p>
<p>However, if you owned a small orbiting satellite that got hit by a piece of space junk, you and your government would have to prove who was at fault. Currently, though, there is <a href="https://theconversation.com/a-giant-piece-of-space-junk-is-hurtling-towards-earth-heres-how-worried-you-should-be-160254?">no globally coordinated space traffic management system</a>. With tens of thousands of tracked pieces of debris in orbit – and multitudes of smaller, untrackable pieces, figuring out what destroyed your satellite would be a very difficult thing to do. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/400834/original/file-20210514-23-qydc5a.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="An image of the Earth surrounded by a cloud of yellow dots." src="https://images.theconversation.com/files/400834/original/file-20210514-23-qydc5a.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/400834/original/file-20210514-23-qydc5a.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=480&fit=crop&dpr=1 600w, https://images.theconversation.com/files/400834/original/file-20210514-23-qydc5a.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=480&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/400834/original/file-20210514-23-qydc5a.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=480&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/400834/original/file-20210514-23-qydc5a.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=603&fit=crop&dpr=1 754w, https://images.theconversation.com/files/400834/original/file-20210514-23-qydc5a.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=603&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/400834/original/file-20210514-23-qydc5a.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=603&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
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<span class="caption">Every dot in this image represents a known piece of space debris.</span>
<span class="attribution"><a class="source" href="https://commons.wikimedia.org/wiki/File:Debris-GEO1280.jpg#/media/File:Debris-GEO1280.jpg">NASA Orbital Debris Program/WikimediaCommons</a></span>
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<h2>Space pollution is the bigger problem</h2>
<p>Current space law has worked so far because the issues have been few and far between and have been dealt with diplomatically. As more and more spacecraft take flight, the risks to property or life will inevitably increase and the Liability Convention may get more use.</p>
<p>But risks to life and property are not the only concerns about a busy sky. While launch providers, satellite operators and insurance companies care about the problem of space debris for its <a href="https://www.bvp.com/atlas/why-removing-space-debris-requires-caution-and-action">effect on space operations</a>, space sustainability advocates argue that the <a href="https://theconversation.com/final-frontiers-space-13171">environment of space has value itself</a> and faces a much greater risk of harm than individuals on Earth. </p>
<p>The mainstream view is that degrading the environment on Earth through pollution or mismanagement is bad because of its <a href="https://www.nationalgeographic.org/encyclopedia/pollution/">negative impact on the environment or living beings</a>. The same is true for space, even if there is no clear direct victim or physical harm. In the <a href="https://www.jaxa.jp/library/space_law/chapter_3/3-2-2-1_e.html">Cosmos 954 settlement</a>, the Canadians claimed that since the Soviet satellite deposited hazardous radioactive debris in Canadian territory, this constituted “damage to property” within the meaning of the Liability Convention. But, as Article 2 of the Outer Space Treaty declares that no state can own outer space or celestial bodies, it is not clear whether this interpretation would apply in the event of harm to objects in space. Space is shaping up to be a new frontier on which the tragedy of the commons can play out.</p>
<p><a href="https://www.nasa.gov/pdf/582393main_OCT-Orbital_Debris_TAGGED.pdf">Removing from orbit existing large objects</a> that could collide with one another would be a great place for governments to start. But if the United Nations or governments agreed on laws that define legal consequences for creating space debris in the first place and punishment for not following best practices, this could help mitigate future pollution of the space environment. </p>
<p>[<em>Understand new developments in science, health and technology, each week.</em> <a href="https://theconversation.com/us/newsletters/science-editors-picks-71/?utm_source=TCUS&utm_medium=inline-link&utm_campaign=newsletter-text&utm_content=science-understand">Subscribe to The Conversation’s science newsletter</a>.]</p>
<p>Such laws would not need to be invented from scratch. The <a href="https://www.unoosa.org/pdf/publications/st_space_49E.pdf">2007 United Nations Space Debris Mitigation guidelines</a> already address the issue of debris prevention. While some countries have transferred these guidelines into national regulations, worldwide implementation is still pending, and there are <a href="http://www.esa.int/Safety_Security/Space_Debris/Mitigating_space_debris_generation">no legal consequences for noncompliance</a>.</p>
<p>The chances of a person being killed by a falling satellite are close to zero. On the off chance it does happen, current space law provides a pretty good framework for dealing with such an event. But just like during the early 20th century on Earth, current laws are focusing on the individual and ignoring the bigger picture of the environment – albeit a cold, dark and unfamiliar one. Adapting and enforcing space law so that it prevents and deters actors from polluting the space environment – and holds them accountable if they break these laws – could help avoid a trash-filled sky.</p>
<p><em>This is an updated version of an article originally published on May 17, 2021. It has been updated to clarify the history of falling space debris.</em></p><img src="https://counter.theconversation.com/content/160757/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Timiebi Aganaba does not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Chances are small that space junk will destroy property or harm a person, and existing space law could deal with such an event. But current law doesn’t address the bigger problem of space pollution.Timiebi Aganaba, Assistant Professor of Space and Society, Arizona State UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1600962021-05-13T19:56:21Z2021-05-13T19:56:21ZWhere do meteorites come from? We tracked hundreds of fireballs streaking through the sky to find out<figure><img src="https://images.theconversation.com/files/398620/original/file-20210504-23-oy71o7.jpg?ixlib=rb-1.1.0&rect=275%2C0%2C7051%2C4891&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption"></span> <span class="attribution"><span class="license">Author provided</span></span></figcaption></figure><p>If asked where meteorites come from, you might reply “from comets”. But according to our new research, which tracked hundreds of fireballs on their journey through the Australian skies, you would be wrong.</p>
<p>In fact, it is very likely that all meteorites — space rocks that make it all the way to Earth — come not from icy comets but from rocky asteroids. Our <a href="https://iopscience.iop.org/article/10.3847/PSJ/abde4b">new study</a> found that even those meteorites with trajectories that look like they arrived from much farther afield are in fact from asteroids that simply got knocked into strange orbits. </p>
<p>We searched through six years’ worth of records from the <a href="https://dfn.gfo.rocks/">Desert Fireball Network</a>, which scans the Australian outback for flaming meteors streaking through the sky. None of what we found came from comets.</p>
<p>That means that of the tens of thousands of meteorites in collections around the world, likely none are from comets, leaving a significant gap in our understanding of the Solar System.</p>
<p>When the Solar System formed, more than 4.5 billion years ago, a disc of dust and debris was swirling around the Sun.</p>
<p>Over time, this material clumped together, forming larger and larger bodies — some so large they swept up everything else in their orbit, and became planets.</p>
<p>Yet some debris avoided this fate and is still floating around today. Scientists traditionally classify these objects into two groups: comets and asteroids.</p>
<p>Asteroids are rockier and drier, because they were formed in the inner Solar System. Comets, meanwhile, formed further out, where ices such as frozen water, methane or carbon dioxide can remain stable — giving them a “dirty snowball” composition.</p>
<p>The best way to understand the origin and evolution of our Solar System is to study these objects. Many space missions have been sent to comets and asteroids over the past few decades. But these are expensive, and only two (<a href="https://theconversation.com/asteroid-dust-brought-back-to-earth-may-explain-where-our-water-came-from-with-hydrogen-clues-116260">Hayabusa</a> and <a href="https://theconversation.com/the-hayabusa2-spacecraft-is-about-to-drop-a-chunk-of-asteroid-in-the-australian-outback-151280">Hayabusa2</a>) have successfully brought back samples.</p>
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Read more:
<a href="https://theconversation.com/the-hayabusa2-spacecraft-is-about-to-drop-a-chunk-of-asteroid-in-the-australian-outback-151280">The Hayabusa2 spacecraft is about to drop a chunk of asteroid in the Australian outback</a>
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<p>Another way to study this material is to sit and wait for it to come to us. If a piece of debris happens to cross paths with Earth, and is large and robust enough to survive hitting our atmosphere, it will land as a meteorite.</p>
<p>Most of what we know about the Solar System’s history comes from these curious space rocks. However, unlike space mission samples, we don’t know exactly where they originated.</p>
<p>Meteorites have been curiosities for centuries, yet it was not until the early 19th century that they were identified as extraterrestrial. They were speculated to come from lunar volcanoes, or even from other star systems. </p>
<p>Today, we know all meteorites come from small bodies in our Solar System. But the big question that remains is: are they all from asteroids, or do some come from comets?</p>
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<strong>
Read more:
<a href="https://theconversation.com/asteroid-dust-brought-back-to-earth-may-explain-where-our-water-came-from-with-hydrogen-clues-116260">Asteroid dust brought back to Earth may explain where our water came from with hydrogen clues</a>
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<p>In total, scientists around the world have collected <a href="https://www.lpi.usra.edu/meteor">more than 60,000 meteorites</a>, mostly from desert regions such as Antarctica or Australia’s Nullarbor Plain.</p>
<p>We now know most of these <a href="https://theconversation.com/link-formed-between-meteorites-and-asteroids-3408">come from the main asteroid belt</a> – a region between Mars and Jupiter.</p>
<p>But might some of them have come not from asteroids, but from comets that originated in the outer reaches of the Solar System? What would such meteorites be like, and how would we find them?</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/398293/original/file-20210503-19-dq0oji.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/398293/original/file-20210503-19-dq0oji.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=334&fit=crop&dpr=1 600w, https://images.theconversation.com/files/398293/original/file-20210503-19-dq0oji.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=334&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/398293/original/file-20210503-19-dq0oji.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=334&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/398293/original/file-20210503-19-dq0oji.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=420&fit=crop&dpr=1 754w, https://images.theconversation.com/files/398293/original/file-20210503-19-dq0oji.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=420&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/398293/original/file-20210503-19-dq0oji.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=420&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
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<span class="caption">Fireball observatory operated by the Desert Fireball Network in South Australia.</span>
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<p>Fortunately, we can actively look for meteorites, rather than hoping to stumble across one lying on the ground. When a space rock is falling through the atmosphere (at this stage, it’s known as a meteor), it begins to heat up and glow — hence why meteors are nicknamed “shooting stars”.</p>
<p>Larger meteors (at least tens of centimetres across) glow brightly enough to be termed “fireballs”. And by training cameras on the sky to spot them, we can track and recover any resulting meteorites.</p>
<p>The largest such network is the <a href="http://fireballsinthesky.com.au/">Desert Fireball Network</a>, which features around 50 cameras covering <a href="https://dfn.gfo.rocks">more than 2.5 million square kilometres</a> of the Australian outback.</p>
<p>The network’s data has resulted in the recovery of six meteorites in Australia, and two more internationally. What’s more, by tracking a fireball’s flight through the atmosphere, we can not only project its path forwards to find where it landed, but also backwards to find out what orbit it was on before it got here.</p>
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<figcaption><span class="caption">Orbital data of debris in the inner Solar System detected by the Desert Fireball Network between 2014-2020.</span></figcaption>
</figure>
<p>Our research, <a href="https://iopscience.iop.org/article/10.3847/PSJ/abde4b">published in The Planetary Science Journal</a>, scoured every fireball tracked by the DFN between 2014 and 2020, in search of possible cometary meteorites. In total, there were 50 fireballs that came from comet-like orbits not associated with a meteor shower.</p>
<p>Unexpectedly, despite the fact that just under 4% of the larger debris was from comet-like orbits, none of the material featured the hallmark “dirty snowball” chemical composition of true cometary material.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/398294/original/file-20210503-19-1qxui2s.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/398294/original/file-20210503-19-1qxui2s.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=360&fit=crop&dpr=1 600w, https://images.theconversation.com/files/398294/original/file-20210503-19-1qxui2s.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=360&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/398294/original/file-20210503-19-1qxui2s.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=360&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/398294/original/file-20210503-19-1qxui2s.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=452&fit=crop&dpr=1 754w, https://images.theconversation.com/files/398294/original/file-20210503-19-1qxui2s.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=452&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/398294/original/file-20210503-19-1qxui2s.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=452&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
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<span class="caption">A meteorite fragment recently found in the Cotswolds town of Winchcombe. Researchers at Curtin University worked with collaborators in the UK to help recover this rare carbonaceous meteorite.</span>
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<p>We concluded that debris from comets breaks up and disintegrates before it even gets close to becoming a meteorite. In turn, this means cometary meteorites are not represented among the tens of thousands of objects in the world’s meteorite collections.</p>
<p>The next question is: if all meteorites are asteroidal, how did some of them end up in such weird, comet-like orbits?</p>
<p>For this to be possible, debris from the main asteroid belt must have been knocked from its original orbit by a collision, close gravitational encounter, or some other mechanism.</p>
<p>Meteorites have given us our most profound insights into the formation and evolution of our solar system. However, it is now clear that these samples represent only part of the whole picture. It is definitely an argument for a sample-return mission to a comet. It’s also testament to the knowledge we can gain from tracking fireballs and the meteorites they sometimes leave behind.</p><img src="https://counter.theconversation.com/content/160096/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Patrick M Shober receives funding from the Australian Research Council as part of the Australian Discovery Project scheme (DP170102529). </span></em></p>You might think lots of meteorites ultimately come from comets. Turns out, you’d be wrong, according to a new study that tracked meteors hurtling through the sky to find out where they came from.Patrick M Shober, Planetary Science PhD Candidate, Curtin UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1605432021-05-10T06:34:18Z2021-05-10T06:34:18ZWant to become a space tourist? You finally can — if you have $250,000 and a will to sign your life away<figure><img src="https://images.theconversation.com/files/399666/original/file-20210510-5598-1n6rxk3.jpg?ixlib=rb-1.1.0&rect=108%2C7%2C5083%2C3238&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><span class="source">Shutterstock</span></span></figcaption></figure><p>Billionaire Jeff Bezos’s space launch company <a href="https://www.blueorigin.com/about-blue">Blue Origin</a> has <a href="https://www.abc.net.au/news/2021-05-06/blue-origin-opens-bidding-for-first-space-tourism-trip/100119676">announced</a> it will sell its first flights into microgravity to the highest bidder.</p>
<p>Blue Origin and its two greatest competitors in the “space tourism” field, <a href="https://visionarybusinessperson.com/spacex-mission-statement-vision-statement/">SpaceX</a> and <a href="https://www.virgingalactic.com/learn/">Virgin Galactic</a>, claim to be advancing humanity through the “democratisation” of space. But these joyrides aren’t opening up access to space for all.</p>
<h2>A changing landscape</h2>
<p>At face value, the prospect of a space tourism industry is exciting. </p>
<p>It promises an easier path to space than the one followed by astronauts, who must go through higher education, intense training and extremely competitive selection processes. Astronauts must also have the right nationality, because few countries have access to human spaceflight programs.</p>
<p>In theory, the opening up of a commercial spaceflight industry should make space more accessible and democratic. But this is only partly the case; what was once the domain of only the richest countries is now an industry headed predominantly by commercial entities. </p>
<p>Adding to this, these companies are prepared to take more risks than government programs because they don’t have to justify their spending — or failures — to the public. Blue Origin and SpaceX have seen many <a href="https://www.theguardian.com/science/2021/feb/02/spacex-starship-rocket-test-flight-explodes-elon-musk">explosions</a> in past tests, yet fans watch with excitement rather than dismay.</p>
<p>This has pushed the rapid development of space technologies. Reusable rockets — particularly SpaceX’s Falcon 9, which just made its <a href="https://www.space.com/spacex-starlink-27-10th-falcon-9-rocket-launch-landing-success">tenth successful launch</a> — have reduced the cost of launching tenfold. </p>
<p>Besides driving down costs, reusable technology is also working to solve the problem of sustainability. </p>
<h2>Considering sustainability</h2>
<p>There have been thousands of launches since 1957, when the first human-made object (Sputnik I) was <a href="https://history.nasa.gov/sputnik.html">launched</a> by the Soviets. Apart from Falcon 9, however, every single launch vehicle has been used once and disposed of immediately — akin to throwing away an aeroplane after one flight. </p>
<p>Launch numbers are increasing each year, with <a href="https://spaceflightnow.com/2021/01/05/u-s-companies-led-by-spacex-launched-more-than-any-other-country-in-2020/">114 carried out in 2020 alone</a>. Over the weekend, the <a href="https://www.abc.net.au/news/2021-05-09/china-long-march-rocket-space-debris-crashes-north-of-maldives/100126702">uncontrolled reentry of debris from China’s Long March 5B rocket</a> made world news because of its sheer size and the risk of damage. It is just one example of the problems of space debris and traffic management. </p>
<p>Safety is a key issue for human spaceflight. Currently, there are about <a href="https://www.statista.com/statistics/264472/number-of-satellites-in-orbit-by-operating-country/">3,400 operational satellites </a> in orbit and <a href="https://www.esa.int/Safety_Security/Space_Debris/Space_debris_by_the_numbers">about 128 million pieces of debris</a>. There are are hundreds of collision risks each day, avoided by expensive and difficult manoeuvres or, if the risk is low enough, operators wait and hope for the best.</p>
<p>If we add more human spaceflight to this traffic, countries will need to adopt stricter requirements to de-orbit satellites at the end of their lives, so they burn up on reentry. Currently, it’s acceptable to de-orbit after 25 years, or to put a satellite into an unused orbit. But this only delays the problem for the future. </p>
<p>Nations will also need to implement the 2019 United Nations guidelines on the <a href="https://www.unoosa.org/oosa/en/ourwork/topics/long-term-sustainability-of-outer-space-activities.html">Long-term Sustainability of Activities in Outer Space</a>. </p>
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Read more:
<a href="https://theconversation.com/space-can-solve-our-looming-resource-crisis-but-the-space-industry-itself-must-be-sustainable-124576">Space can solve our looming resource crisis – but the space industry itself must be sustainable</a>
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<p>The environmental impact of launches are another important factor. SpaceX’s Falcon 9 burns as much fuel as an <a href="https://www.latimes.com/business/story/2020-01-30/space-launch-carbon-emissions">average car would over 200 years</a>, for a single launch. </p>
<p>On the ground there are impacts on terrain and waterways, which we have to keep in mind when building future launch sites in Australia. Launch permits currently require environmental <a href="https://www.legislation.gov.au/Details/F2019L01118">impact statements</a>, but these should include long-term effects and carbon footprints as well.</p>
<h2>Keeping billionaires in check</h2>
<p>In the <a href="https://www.cnbc.com/2020/09/26/space-tourism-how-spacex-virgin-galactic-blue-origin-axiom-compete.html">coming years</a>, it will be crucial for independent spaceflight companies to be tightly regulated. </p>
<p>Virgin Galactic has long advocated a “<a href="https://www.bloomberg.com/news/articles/2019-01-24/under-armour-is-blasting-off-into-a-new-market-spacesuits">shirtsleeve</a>” environment wherein customers can experience the luxury of spaceflight unhindered by awkward spacesuits. But the <a href="https://www.thespacereview.com/article/2695/1">death of one of its test pilots in 2014</a> is evidence spaceflight remains <a href="https://en.wikipedia.org/wiki/List_of_spaceflight-related_accidents_and_incidents#Astronaut_fatalities">dangerous</a>. High altitudes and pressure require more precaution and less concern for comfort.</p>
<p>Although regulators such as the US Federal Aviation Administration have strict safety requirements for space tourism, pressurised spacesuits are not among them — but they should be. Also, space tourism operators can require passengers to sign legal waivers of liability, in case of accident.</p>
<p>And while it’s laudable SpaceX and Blue Origin are making technological leaps, there is little in their business plans that speaks to <a href="https://papers.ssrn.com/sol3/papers.cfm?abstract_id=3670381">diversity, inclusivity and global accessibility</a>. The first space tourists were all wealthy entrepreneurs. </p>
<p>In 2001 Dennis Tito <a href="https://www.travelandleisure.com/trip-ideas/space-astronomy/dennis-tito-first-space-tourist">paid his way</a> to a seat on a Russian Soyuz rocket to visit the International Space Station (ISS). Since then, there have been <a href="https://didyouknow.org/lists/spacetourists/">eight more space tourists</a>, each paying between US$20 million and US$30 million to fly through the Russian program. </p>
<p>In 2022, the <a href="https://www.travelandleisure.com/trip-ideas/space-astronomy/axiom-first-private-astronaut-crew-international-space-station">Axiom crew</a> is scheduled to fly on a SpaceX Dragon flight to the ISS. Each of the three wealthy, white, male passengers will have paid US$55 million for the privilege. Meanwhile, Blue Origin’s upcoming auction will last five weeks, the highest bidder winning a seat for a few minutes of microgravity. </p>
<p>Virgin Galactic’s 90-minute joyrides, also scheduled to fly as early as 2022, have already <a href="https://www.virgingalactic.com/register/">sold for US$250,000</a>. Future tickets are expected to cost more.</p>
<h2>A matter of time?</h2>
<p>Of course, conventional recreational air travel was also <a href="https://airandspace.si.edu/exhibitions/america-by-air/online/innovation/innovation15.cfm">originally for the wealthy</a>. Early cross-continental flights in the United States costed about half the price of a new car. But technological advances and commercial competition meant by 2019 (pre-COVID) there were nearly <a href="https://www.statista.com/statistics/564717/airline-industry-passenger-traffic-globally/">five million people flying daily</a>.</p>
<p>Perhaps it’s only a matter of time before space tourism becomes similarly accessible. Ideally, this would mean being able to fly from Sydney to London <a href="https://www.nasaspaceflight.com/2020/12/earth-to-earth-supersonic-airliners/">in a matter of hours</a>. </p>
<p>Then again, spaceflight carries much greater risks and much greater costs than airflight, even with reusable rockets. It’s going to be a long time before these costs are driven down enough to allow the “democratisation” of space. </p>
<p>This is a compelling narrative which commercial spaceflight companies are eager to adopt. But there will always be a portion of society that won’t have access to this future. Indeed, as <a href="https://www.denofgeek.com/movies/elysium-and-the-gap-between-rich-and-poor-in-sci-fi-cinema/">many science-fiction stories</a> predict, human spaceflight or habitation in space may only ever be accessible to the very wealthy.</p>
<p>We know there are benefits to space-based technologies — from tracking climate change, to enabling global communications and health services, to learning from scientific experiments on the ISS. But when it comes to space tourism specifically, the payback for the average person is less clear. </p>
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<a href="https://theconversation.com/yuri-gagarins-boomerang-the-tale-of-the-first-person-to-return-from-space-and-his-brief-encounter-with-aussie-culture-157043">Yuri Gagarin's boomerang: the tale of the first person to return from space, and his brief encounter with Aussie culture</a>
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<img src="https://counter.theconversation.com/content/160543/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Cassandra Steer is a member of the Space Industry Association of Australia. </span></em></p>Several spaceflights scheduled over the next few years will take non-astronauts to space. But it’s not certain this privilege will ever extend to anyone beyond the extremely wealthy.Cassandra Steer, Senior Lecturer, ANU College of Law; Mission Specialist, ANU Institute for Space, Australian National UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1602542021-05-04T08:45:29Z2021-05-04T08:45:29ZA giant piece of space junk is hurtling towards Earth. Here’s how worried you should be<p>A large piece of space debris, possibly weighing several tonnes, is currently on an uncontrolled reentry phase (that’s space speak for “out of control”), and parts of it are <a href="https://spacenews.com/huge-rocket-looks-set-for-uncontrolled-reentry-following-chinese-space-station-launch">expected to crash down to Earth</a> over the next few weeks. </p>
<p>If that isn’t worrying enough, it is impossible to predict exactly where the pieces that don’t burn up in the atmosphere might land. Given the object’s <a href="https://orbit.ing-now.com/satellite/48275/2021-035b/cz-5b/">orbit</a>, the possible landing points are <a href="https://spacenews.com/huge-rocket-looks-set-for-uncontrolled-reentry-following-chinese-space-station-launch/">anywhere</a> in a band of latitudes “a little farther north than New York, Madrid and Beijing and as far south as southern Chile and Wellington, New Zealand”. </p>
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<span class="caption">Changing altitude of the Long March 5B rocket now in uncontrolled descent back to Earth.</span>
<span class="attribution"><span class="source">orbit.ing-now.com</span></span>
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<p>The debris is part of the Long March 5B rocket that recently successfully launched China’s first module for its proposed space station. The incident comes roughly a year after another similar Chinese rocket <a href="https://weather.com/news/news/2020-05-12-pieces-of-a-chinese-rocket-fell-uncontrollably-to-earth">fell to Earth</a>, landing in the Atlantic Ocean but not before it reportedly left a trail of debris in the African nation of Cote D'Ivoire. </p>
<p>At the time, experts noted this was one of the largest pieces of human-made debris ever to fall to Earth. We cannot say with certainty what fate awaits this latest piece of space junk.</p>
<h2>Litter from space</h2>
<p>Australia already holds the record in the category of “who can be hit by the biggest piece of space junk”. In 1979, the 77-tonne US space station SkyLab <a href="https://www.abc.net.au/news/2019-07-12/four-decades-on-from-skylabs-descent-from-space/11249626">disintegrated over Western Australia</a>, peppering the area around the southern coastal town of Esperance with fragments. </p>
<p>At the time, the event was met with with excitement and a sense of lightheartedness, and many pieces were collected by space enthusiasts. Esperance shire council flippantly issued NASA with a <a href="https://tracesmagazine.com.au/2018/04/when-western-australia-fined-nasa/">fine for littering</a>, and a US radio station later raised enough money to pay the debt.</p>
<p>Although there have been no recorded deaths or serious injuries from people being hit by space debris, that’s no reason to think it’s not dangerous. Just one year before SkyLab’s demise, a Soviet remote sensing (spy) satellite, Cosmos 954, <a href="https://www.amusingplanet.com/2020/05/cosmos-954-nuke-that-fell-from-space.html">plummeted into a barren region</a> of Canada’s Northwest Territories, spreading radioactive debris over several hundred square kilometres. </p>
<p>With the Cold War at its height, the sensitivity of the nuclear technology on board Cosmos 954 led to an unfortunate delay in locating and cleaning up the wreckage, because of the distrust between the Soviet Union and the Canadian/US recovery effort.</p>
<p>The clean-up operation took months but located only a portion of the debris. Canada billed the Soviet Union more than C$6 million, having spent millions more, but was ultimately paid only C$3 million.</p>
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Read more:
<a href="https://theconversation.com/trash-or-treasure-a-lot-of-space-debris-is-junk-but-some-is-precious-heritage-82832">Trash or treasure? A lot of space debris is junk, but some is precious heritage</a>
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<p>Since the late 1970s, pieces of space debris have fallen to Earth regularly and are viewed with increasing concern. Of course, more than 70% of Earth is covered by oceans, and only a minuscule fraction of the remaining 30% is covered by your house. But for anyone falling foul of the extremely long odds, the consequences would be truly disastrous.</p>
<p>It was just a quirk of fate that Cosmos 954 did not land on Toronto or Quebec City, where the radioactive fallout would have necessitated a large-scale evacuation. In 2007, pieces of debris from a Russian satellite <a href="https://en.mercopress.com/2007/03/28/lan-chile-airbus-has-near-miss-from-russian-space-junk">narrowly missed a Chilean passenger plane</a> flying between Santiago and Auckland. As we send more objects into space, the chances of a calamitous crash-landing will only increase.</p>
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Read more:
<a href="https://theconversation.com/two-satellites-just-avoided-a-head-on-smash-how-close-did-they-come-to-disaster-130794">Two satellites just avoided a head-on smash. How close did they come to disaster?</a>
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<h2>Who pays to clean up the mess, anyway?</h2>
<p>International law sets out a compensation regime that would apply in many circumstances of damage on Earth, as well as when satellites <a href="https://theconversation.com/its-not-how-big-your-laser-is-its-how-you-use-it-space-law-is-an-important-part-of-the-fight-against-space-debris-158790">collide in space</a>. The <a href="https://www.unoosa.org/pdf/gares/ARES_26_2777E.pdf">1972 Liability Convention</a>, a UN treaty, imposes liability on “launching states” for damage caused by their space objects, which includes an absolute liability regime when they crash to Earth as debris. </p>
<p>In the case of the Long March 5B, this would impose potential liability on China. The treaty has only been invoked once before (<a href="https://www.jaxa.jp/library/space_law/chapter_3/3-2-2-1_e.html">for the Cosmos 954 incident</a>) and therefore may not be regarded as a powerful disincentive. However, it is likely to come into play in the future in a more crowded space environment, and with more uncontrolled reentries. Of course, this legal framework applies only after the damage occurs. </p>
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<a href="https://theconversation.com/its-not-how-big-your-laser-is-its-how-you-use-it-space-law-is-an-important-part-of-the-fight-against-space-debris-158790">It's not how big your laser is, it's how you use it: space law is an important part of the fight against space debris</a>
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<p>Other international guidelines regarding <a href="https://www.unoosa.org/pdf/publications/st_space_49E.pdf">debris mitigation</a> and <a href="https://www.unoosa.org/oosa/en/ourwork/topics/long-term-sustainability-of-outer-space-activities.html">long-term sustainability of space activities</a> set out voluntary standards intended to limit the probability of collisions in space, and minimise the breakup of satellites either during or after their missions. </p>
<p>Some satellites can be moved into a <a href="https://en.wikipedia.org/wiki/Graveyard_orbit">graveyard orbit</a> at the end of their operational life. While this works well for certain specific orbits at a relatively high altitude, it is impractical and hazardous to start moving the vast majority of satellites around between orbital planes. Most of the millions of pieces of space junk are destined either to orbit in an uncontrollable manner for many years or, if they are in low Earth orbit, to gradually descend towards the Earth, hopefully burning up in the atmosphere before contact with terra firma. </p>
<p>A globally coordinated space traffic management system will be vital to avoid collisions that would result in loss of control of satellites, leaving them to tumble helplessly in orbit or fall back to Earth.</p>
<p>Comprehensively tracking every satellite’s movement and functionality is even harder than it sounds, because it would inevitably require countries to be willing to share information they often currently regard as confidential matters of national security.</p>
<p>But, ultimately, global cooperation is essential if we are to avoid an unsustainable future for our space activities. In the meantime, don’t forget to gaze upwards every now and then — you might spot some of the most spectacular litter on the planet.</p><img src="https://counter.theconversation.com/content/160254/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Steven Freeland is a Director of the International Institute of Space Law.</span></em></p>China’s Long March 5B rocket, after a successful blast-off in April to deliver a space station module, is now on track to crash-land somewhere with a latitude between New York and New Zealand.Steven Freeland, Professorial Fellow, Bond University / Emeritus Professor of International Law, Western Sydney University, Western Sydney UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1587902021-04-14T20:08:01Z2021-04-14T20:08:01ZIt’s not how big your laser is, it’s how you use it: space law is an important part of the fight against space debris<figure><img src="https://images.theconversation.com/files/394955/original/file-20210414-19-q7ofm4.jpg?ixlib=rb-1.1.0&rect=5%2C10%2C3497%2C2462&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><span class="source">ESA</span></span></figcaption></figure><p>Space is getting crowded. More than 100 million tiny pieces of debris are spinning in Earth orbit, along with tens of thousands of bigger chunks and around <a href="https://www.ucsusa.org/resources/satellite-database">3,300 functioning satellites</a>.</p>
<p>Large satellite constellations such as Starlink are becoming more common, infuriating astronomers and <a href="https://www.abc.net.au/news/2021-04-13/what-were-these-lights-in-the-sky-eastern-australia/100064630">baffling casual skywatchers</a>. In the coming decade, we may see many <a href="https://www.cnbc.com/2019/12/14/spacex-oneweb-and-amazon-to-launch-thousands-more-satellites-in-2020s.html">more satellites launched</a> than in all of history up to now.</p>
<p>Collisions between objects in orbit are getting harder to avoid. Several technologies for getting space debris out of harm’s way have been proposed, most recently the plan from Australian company Electro Optic Systems (EOS) to use a <a href="https://www.spaceconnectonline.com.au/operations/4828-eos-unveils-new-space-debris-threat-mitigation-laser">pair of ground-based lasers</a> to track debris and “nudge” it away from potential collisions or even out of orbit altogether.</p>
<p>Tools like this will be in high demand in coming years. But alongside new technology, we also need to work out the best ways to regulate activity in space and decide who is responsible for what.</p>
<h2>Active debris removal</h2>
<p>EOS’s laser system is just one of a host of “active debris removal” (ADR) technologies proposed over the past decade. Others involve sails, tentacles, nets, claws, harpoons, magnets and foam. </p>
<p>Outside Australia, Japan-based company <a href="https://astroscale.com/">Astroscale</a> is currently testing its <a href="https://astroscale.com/astroscale-celebrates-successful-launch-of-elsa-d/">ELSA system</a> for capturing debris with magnets. The British RemoveDEBRIS project has been experimenting with <a href="https://www.surrey.ac.uk/surrey-space-centre/missions/removedebris">nets and harpoons</a>. The European Space Agency (ESA) is engaged in various debris-related missions including the <a href="https://www.sciencemag.org/news/2020/12/europe-plans-space-claw-capture-orbiting-junk">ClearSpace-1</a> “space claw”, designed to grapple a piece of debris and drag it down to a lower orbit where the claw and its captured prey will end their lives in a fiery embrace. </p>
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<img alt="" src="https://images.theconversation.com/files/394951/original/file-20210414-22-8yzo6o.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/394951/original/file-20210414-22-8yzo6o.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=338&fit=crop&dpr=1 600w, https://images.theconversation.com/files/394951/original/file-20210414-22-8yzo6o.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=338&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/394951/original/file-20210414-22-8yzo6o.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=338&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/394951/original/file-20210414-22-8yzo6o.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=424&fit=crop&dpr=1 754w, https://images.theconversation.com/files/394951/original/file-20210414-22-8yzo6o.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=424&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/394951/original/file-20210414-22-8yzo6o.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=424&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
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<span class="caption">Astroscale’s ELSA system will use magnets to capture space debris.</span>
<span class="attribution"><span class="source">Astroscale</span></span>
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<h2>Close calls are becoming more common</h2>
<p>Space debris poses a very real threat, and interest in ADR technologies is growing rapidly. The ESA <a href="https://www.esa.int/Safety_Security/Space_Debris/Space_debris_by_the_numbers">estimates</a> there are currently 128 million pieces of debris smaller than 1cm, about 900,000 pieces of debris 1–10cm in length, and around 34,000 pieces larger than 10cm in Earth orbit. </p>
<p>Given the <a href="https://science.howstuffworks.com/satellite6.htm">high speed</a> of objects in space, any collision – with debris or a “live” satellite – could create thousands more pieces of debris. These could create more collisions and more debris, potentially triggering an exponential increase in debris called the “<a href="https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1029/JA083iA06p02637">Kessler effect</a>”. Eventually we could see a “debris belt” around Earth, making space less accessible. </p>
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Read more:
<a href="https://theconversation.com/two-satellites-just-avoided-a-head-on-smash-how-close-did-they-come-to-disaster-130794">Two satellites just avoided a head-on smash. How close did they come to disaster?</a>
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<p>In recent times, we have seen several “near collisions” in space. In late January 2020, we all watched helplessly as two much larger “dead” satellites – IRAS and GGSE-4 – <a href="https://theconversation.com/two-satellites-just-avoided-a-head-on-smash-how-close-did-they-come-to-disaster-130794">passed within metres</a> of each other. NASA often moves the International Space Station when it calculates a higher-than-normal risk of collision with debris. </p>
<h2>More satellites, more risk</h2>
<p>The problem of space debris is becoming <a href="https://spacenews.com/rise-of-the-megaconstellations-breathes-life-into-active-debris-removal-schemes/">more urgent</a> as more <a href="https://spacenews.com/euroconsult-smallsat-launches-to-hit-all-time-high-in-2020/">large constellations of small satellites</a> are launched. In 2019, the ESA sent one of its Earth-observing satellites on a small detour to avoid a high possibility of a <a href="https://www.esa.int/Safety_Security/ESA_spacecraft_dodges_large_constellation">collision</a> with one of SpaceX’s Starlink satellites. </p>
<p>In just the past few days, satellites from One Web and Starlink came <a href="https://www.theverge.com/2021/4/9/22374262/oneweb-spacex-satellites-dodged-potential-collision-orbit-space-force">perilously close</a> to a collision. If the <a href="https://www.cnbc.com/2019/12/14/spacex-oneweb-and-amazon-to-launch-thousands-more-satellites-in-2020s.html">well-publicised plans</a> of just a few large corporations come to fruition, the number of objects launched into space over the coming years will dwarf by a factor of <em>up to ten times</em> the total number launched over the six decades since the first human-made object (Sputnik 1) was sent into orbit in 1957. </p>
<h2>Space law can help</h2>
<p>Any feasible technology to alleviate the problem of space debris should be thoroughly explored. At the same time, actively removing debris raises political and legal problems. </p>
<p>Space is an area beyond national jurisdiction. Like the high seas, space is governed through international law. The 1967 <a href="https://www.unoosa.org/oosa/en/ourwork/spacelaw/treaties/introouterspacetreaty.html">Outer Space Treaty</a> and the four other international treaties that followed set out a framework and key principles to guide responsible behaviour. </p>
<p>While the engineers might envisage nets and harpoons, international law is bad news for aspiring space “pirates”. Any space object or part of a space object, functional or not, remains under the jurisdiction of a “State of registry”. </p>
<p>Under international law, to capture, deflect or interfere with a piece of debris would constitute a “national activity in outer space” – meaning the countries that authorised or agreed to the ADR manoeuvre have an international legal responsibility, even if the action is carried out by a private company. In addition, if something goes wrong (as we know, space is hard), a liability regime applies to the “launching States” under the <a href="https://www.unoosa.org/oosa/en/ourwork/spacelaw/treaties/introliability-convention.html">applicable Treaty</a>, which would include those countries involved in the launch of the ADR vehicle.</p>
<h2>The rules of the road</h2>
<p>Beyond the legal technicalities, debris removal raises complex policy, geopolitical, economic, and social challenges. Whose responsibility is it to remove debris? Who should pay? What rights do non-spacefaring nations have in discussions? Which debris should be <a href="https://theconversation.com/saving-space-junk-our-cultural-heritage-in-orbit-6025">preserved as heritage</a>? </p>
<p>And if a State develops the capability to remove or deflect space debris, how can we be sure they won’t use it to remove or deflect another country’s “live” satellites?</p>
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<a href="https://theconversation.com/saving-space-junk-our-cultural-heritage-in-orbit-6025">Saving space junk, our cultural heritage in orbit</a>
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<p>Experts are working to recognise and determine the appropriate regulatory “rules of the road”. The United Nations <a href="https://www.unoosa.org/oosa/en/ourwork/copuos/index.html">Committee on the Peaceful Uses of Outer Space</a> (COPUOS) deals with space governance, and it has had “legal mechanisms relating to space debris mitigation and remediation measures” on its agenda for years. There are already some widely-accepted and practical guidelines for <a href="https://www.unoosa.org/pdf/publications/st_space_49E.pdf">debris mitigation</a> and <a href="https://www.unoosa.org/oosa/en/ourwork/topics/long-term-sustainability-of-outer-space-activities.html">long-term sustainability</a> of space activities, but each proposed solution brings with it other questions.</p>
<p>In the end, any debris remediation activity will require a negotiated agreement between each of the relevant parties to ensure these legal and other questions are addressed. Eventually, we might see a standardised process emerge, in coordination with an international system of space traffic management. </p>
<p>The future of humanity is inextricably tied to our ability to ensure a viable long-term future for space activities. Developing new debris removal methods, and the legal frameworks to make them usable, are important steps towards finding ways to co-exist with our planet and promote the ongoing safety, security and sustainability of space.</p><img src="https://counter.theconversation.com/content/158790/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Steven Freeland is a Director of the International Institute of Space Law. </span></em></p><p class="fine-print"><em><span>Annie Handmer's research is supported by an Australian Government Research Training Program stipend. She sits on the Advisory Council of the Space Industry Association of Australia, is a member of the Space Generation Advisory Council, and is the host and creator of the Space Junk Podcast. </span></em></p>Earth orbit is filling up with satellites and space junk. Technological fixes can only go so far to deal with the problem.Steven Freeland, Professorial Fellow, Bond University / Emeritus Professor of International Law, Western Sydney University, Western Sydney UniversityAnnie Handmer, PhD candidate, School of History and Philosophy of Science, University of SydneyLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1375722020-05-13T11:40:08Z2020-05-13T11:40:08ZSpace junk: Astronomers worry as private companies push ahead with satellite launches<figure><img src="https://images.theconversation.com/files/334631/original/file-20200513-156641-95sq2q.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Space junk is making low Earth orbit crowded.</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-illustration/space-junk-orbiting-around-earth-conceptual-233084350">Johan Swanepoel/Shuttertock</a></span></figcaption></figure><p>Since the launch of Sputnik 1 in 1957, the lower orbit around the Earth has become an increasingly congested environment with more than 2,200 satellite launches to date. Those satellites – along with launch vehicle components and debris from mechanical disintegration, collisions and explosions – now fill this region with a “fog” of space debris.</p>
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<p><em>You can listen to more article from The Conversation, narrated by Noa, <a href="https://theconversation.com/uk/topics/audio-narrated-99682">here</a>.</em> </p>
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<p>And it’s getting busier. In the last few weeks, SpaceX <a href="https://www.space.com/space-starlink-satellites-launch-rocket-landing-success-april-2020.html">has launched 60 new satellites</a> as part of its Starlink programme. This brings the total to currently around 400 Starlink satellites in low Earth orbit as part of a programme that aims to bring cheap, satellite-based internet access to everyone. Eventually, this programme could place nearly 12,000 satellites in orbit around the Earth.</p>
<p>With Amazon, Canada’s <a href="https://www.telesat.com/services/leo/phase-1">Telesat</a> and others <a href="https://www.cnbc.com/2019/12/14/spacex-oneweb-and-amazon-to-launch-thousands-more-satellites-in-2020s.html">planning satellite constellations</a> of similar scale, low Earth orbit is becoming ever more crowded. </p>
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<p>The debris ranges in size from a few microns to many metres. <a href="https://www.stugrey.com/">Stuart Grey</a>, an aerospace engineer at the University of Strathclyde, has produced a stunning visualisation that highlights the more than 20,000 objects over 10cm in size now orbiting the Earth (see video above). But there are many millions of particles 1mm in size and smaller.</p>
<h2>Closing our window on the universe?</h2>
<p>Amateur astronomers are <a href="https://edition.cnn.com/2020/04/21/tech/starlink-satellites-stargazers-complaints-scli-intl-gbr/index.html">already expressing concern</a> over the increasing number of bright, moving objects in the night sky. But the worry is perhaps much greater for the professionals.</p>
<p>Crowding in low Earth orbit has inevitable consequences for ground-based astronomers. Bright surfaces on satellites can reflect rays from the sun – giving rise to a burst of sunlight directed towards the surface of the Earth. Such intense bursts of light are much stronger than the weak light sources typically being observed by astronomers and will impede observations of distant objects in space. </p>
<p>Billions have already been spent on existing optical telescopes, and many more billions will be poured into new platforms in the next decade, such as the <a href="https://www.eso.org/sci/facilities/eelt/">European Extremely Large Telescope</a> being built on the Atacama plateau in Chile. There is intense competition for observing time on such resources, so any potential threat from satellite reflections must be taken seriously as they may make some of the observations driving our understanding of the evolution of the universe impossible.</p>
<p>SpaceX has assured the public that Starlink will not contribute to this problem and says it <a href="https://time.com/5225670/spacex-space-junk-cleaner-launch/">has been taking steps</a> to mitigate the impacts of its satellites on observational astronomy – even to the extent of testing whether a black coating on its satellites can reduce visibility, and adjusting some of the satellites’ orbits if necessary.</p>
<p>With some 3% of its planned constellation launched, SpaceX is at least responding to the concerns raised by astronomers. Hopefully other agencies planning satellite constellation launches will also be upfront with their plans to reduce this serious problem to astronomical observation.</p>
<p>But crowding in low Earth orbit also has consequences for satellites and other space vehicles, including those designed to carry humans. To achieve orbit, satellites seek a balance between their speed and the effect of Earth’s gravity on them. The speed with which a satellite must travel to achieve this balance depends on its altitude above Earth. The nearer to Earth, then the faster the required orbital speed. </p>
<p>At an altitude of 124 miles (200km), the required orbital velocity is a little more than 17,000 miles per hour (about 7.4 km/s). Any object shed by a satellite or other vehicle in orbit will maintain the same orbital speed. Collisions between such objects can therefore occur at combined speeds of potentially up to 34,000 mph at 124 miles (if it is head-on). The effects of such impacts can be serious for astronauts and space stations – as the dramatic opening scenes of the 2013 movie Gravity depict. </p>
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<p>There is impact shielding on satellites and space vehicles which is designed to stop objects smaller than 1cm crashing into them. At best, the shielding will do so – though the electromagnetic impulse created may interfere with electronic systems. At worst, larger pieces of space junk could penetrate the vehicles. This could result in internal damage and disintegration that threaten the safety of the mission.</p>
<p>Space agencies such as NASA and ESA have therefore established <a href="https://www.orbitaldebris.jsc.nasa.gov/">orbital debris research programmes</a> to observe such debris and develop strategies to control its effects. </p>
<p>There is little doubt that, with the increasing use and commercialisation of space, we boost the risk of catastrophic events associated with orbital debris. Agencies, both state and commercial, must recognise this and support efforts to reduce the likelihood of such events by taking steps to remove existing debris and reduce the potential for further debris by removing redundant satellites and other space vehicles. For example the <a href="https://www.surrey.ac.uk/news/harpoon-successfully-captures-space-debris">RemoveDEBRIS satellite</a> uses an on-board harpoon to capture junk.</p>
<p>Only when we resolve the problem of space junk will our window on, and pathway to, space be truly fully open.</p><img src="https://counter.theconversation.com/content/137572/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Martin McCoustra does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>SpaceX recently launched 60 satellites into orbit around Earth as part of its Starlink programme.Martin McCoustra, ScotCHEM Chair in Chemical Physics, Heriot-Watt UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1307942020-01-30T03:36:39Z2020-01-30T03:36:39ZTwo satellites just avoided a head-on smash. How close did they come to disaster?<figure><img src="https://images.theconversation.com/files/312729/original/file-20200130-41532-ve90i6.jpg?ixlib=rb-1.1.0&rect=8%2C0%2C799%2C622&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">The now defunct Infrared Astronomical Telescope was one of the satellites involved in the near-collision.</span> <span class="attribution"><a class="source" href="https://commons.wikimedia.org/wiki/File:IRAS_in_orbit.jpg">NASA/JPL</a></span></figcaption></figure><p>It appears we have missed another close call between two satellites – but how close did we really come to a catastrophic event in space?</p>
<p>It all began with a <a href="https://twitter.com/LeoLabs_Space/status/1221908248305061889">series of tweets from LeoLabs</a>, a company that uses radar to track satellites and debris in space. It predicted that two obsolete satellites orbiting Earth had a 1 in 100 chance of an almost direct head-on collision at 9:39am AEST on 30 January, with potentially devastating consequences. </p>
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<p>LeoLabs estimated that the satellites could pass within 15-30m of one another. Neither satellite could be controlled or moved. All we could do was watch whatever unfolded above us.</p>
<p>Collisions in space can be disastrous and can send high-speed debris in all directions. This endangers other satellites, future launches, and especially crewed space missions. </p>
<p>As a point of reference, NASA often moves the International Space Station when the risk of collision is just 1 in 100,000. Last year the European Space Agency moved one of its satellites when the likelihood of collision with a SpaceX satellite was estimated at 1 in 50,000. However, this increased to 1 in 1,000 when the US Air Force, which maintains perhaps the most comprehensive catalogue of satellites, provided more detailed information.</p>
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<a href="https://theconversation.com/you-me-and-debris-australia-should-help-clear-space-junk-9919">You, me and debris: Australia should help clear 'space junk'</a>
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<p>Following LeoLabs’ warning, other organisations such as the Aerospace Corporation began to provide similarly worrying predictions. In contrast, calculations based on publicly available data were far more optimistic. Neither the US Air Force nor NASA issued any warning. </p>
<p>This was notable, as the United States had a role in the launch of both satellites involved in the near-miss. The first is the <a href="https://www.jpl.nasa.gov/missions/infrared-astronomical-satellite-iras/">Infrared Astronomical Satellite (IRAS)</a>, a large space telescope weighing around a tonne and launched in 1983. It successfully completed its mission later that year and has floated dormant ever since. </p>
<p>The second satellite has a slightly more intriguing story. Known as <a href="https://www.n2yo.com/satellite/?s=2828">GGSE-4</a>, it is a formerly secret government satellite launched in 1967. It was part of a much larger project to capture radar emissions from the Soviet Union. This particular satellite also contained an experiment to explore ways to stabilise satellites using gravity. </p>
<p>Weighing in at 83kg, it is much smaller than IRAS, but it has a very unusual and unfortunate shape. It has an 18m protruding arm with a weight on the end, thus making it a much larger target. </p>
<p>Almost 24 hours later, <a href="https://twitter.com/LeoLabs_Space/status/1222304111527374853">LeoLabs tweeted again</a>. It downgraded the chance of a collision to 1 in 1,000, and revised the predicted passing distance between the satellites to 13-87m. Although still closer than usual, this was a decidedly smaller risk. But less than 15 hours after that, the company <a href="https://twitter.com/LeoLabs_Space/status/1222547865567887361">tweeted yet again</a>, raising the probability of collision back to 1 in 100, and then to a very alarming 1 in 20 after learning about the shape of GGSE-4. </p>
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<p>The good news is that the two satellites appear to have missed one another. Although there were a handful of eyewitness accounts of the IRAS satellite appearing to pass unharmed through the predicted point of impact, it can still take a few hours for scientists to confirm that a collision did not take place. LeoLabs has <a href="https://twitter.com/LeoLabs_Space/status/1222702184711757825">since confirmed</a> it has not detected any new space debris. </p>
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<p>But why did the predictions change so dramatically and so often? What happened?</p>
<h2>Tricky situation</h2>
<p>The real problem is that we don’t really know precisely where these satellites are. That requires us to be extremely conservative, especially given the cost and importance of most active satellites, and the dramatic consequences of high-speed collisions.</p>
<p>The tracking of objects in space is often called <a href="https://www.unsw.adfa.edu.au/space-research/research-themes/space-situational-awareness">Space Situational Awareness</a>, and it is a very difficult task. One of the best methods is radar, which is expensive to build and operate. Visual observation with telescopes is much cheaper but comes with other complications, such as weather and lots of moving parts that can break down. </p>
<p>Another difficulty is that our models for predicting satellites’ orbits don’t work well in lower orbits, where drag from Earth’s atmosphere can become a factor.</p>
<p>There is yet another problem. Whereas it is in the best interest of commercial satellites for everyone to know exactly where they are, this is not the case for military and spy satellites. Defence organisations do not share the full list of objects they are tracking. </p>
<p>This potential collision involved an ancient spy satellite from 1967. It is at least one that we can see. Given the difficulty of just tracking the satellites that we know about, how will we avoid satellites that are trying their hardest not to be seen?</p>
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Read more:
<a href="https://theconversation.com/trash-or-treasure-a-lot-of-space-debris-is-junk-but-some-is-precious-heritage-82832">Trash or treasure? A lot of space debris is junk, but some is precious heritage</a>
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<p>In fact, much research has gone into building stealth satellites that are invisible from Earth. Even commercial industry is considering making satellites that are harder to see, partly in response to astronomers’ own concerns about objects blotting out their view of the heavens. SpaceX is considering building “dark satellites” the reflect less light into telescopes on Earth, which will only make them harder to track.</p>
<h2>What should we do?</h2>
<p>The solution starts with developing better ways to track satellites and space debris. Removing the junk is an important next step, but we can only do that if we know exactly where it is. </p>
<p>Western Sydney University is developing <a href="https://www.westernsydney.edu.au/icns/astrosite">biology-inspired cameras</a> that can see satellites during the day, allowing them to work when other telescopes cannot. These sensors can also see satellites when they move in front of bright objects like the Moon.</p>
<p>There is also no clear international space law or policy, but a strong need for one. Unfortunately, such laws will be impossible to enforce if we cannot do a better job of figuring out what is happening in orbit around our planet.</p><img src="https://counter.theconversation.com/content/130794/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Gregory Cohen receives funding for space applications of neuormorphic imaging from the Royal Australian Air Force (RAAF), the United States Air Force Office of Scientific Research (AFOSR), and the Defense Innovation Hub (DIH).</span></em></p>Two defunct satellites passed within metres of one another, prompting renewed focus on the dangers of space debris. But with many satellites treated as military secrets, how do we track the hazards?Gregory Cohen, Associate Professor, Western Sydney UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1216022019-08-08T12:09:29Z2019-08-08T12:09:29ZTardigrades: we’re now polluting the moon with near indestructible little creatures<figure><img src="https://images.theconversation.com/files/287398/original/file-20190808-144868-10mhlpm.jpg?ixlib=rb-1.1.0&rect=0%2C157%2C3000%2C2070&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-illustration/tardigrade-water-bear-3d-rendered-illustration-535109380?src=cjaqEapOnY5_mpZ177xWvA-1-0">3DStock/Shutterstock</a></span></figcaption></figure><p>An Israeli spacecraft <a href="http://www.planetary.org/explore/space-topics/space-missions/beresheet.html">called Beresheet</a> almost made it to <a href="https://theconversation.com/uk/topics/moon-606">the moon</a> in April. It took a selfie with the lunar surface in the background, but then lost contact with Earth and presumably crashed onto the lunar surface. Now <a href="https://www.wired.com/story/a-crashed-israeli-lunar-lander-spilled-tardigrades-on-the-moon/">it’s been revealed</a> that the mission was carrying a cargo of dehydrated microscopic lifeforms known as tardigrades.</p>
<p>Beresheet was the first stage of a privately-funded initiative to <a href="https://www.archmission.org/">transfer living DNA to the moon</a>. The project is designed to act as Noah’s Ark Mark II, providing a repository from which plants and animals could be regenerated to repopulate the Earth should a catastrophe akin to a flood of biblical proportions overtake the planet.</p>
<p>Whether the project is far-sighted or foolish, what has roused interest is the fact that, as a result of the crash, the tardigrades may now be scattered across the lunar surface. They are hardy creatures and could probably survive on the moon for a long time. Is this a matter of concern? I believe so, but possibly not for the reasons you might think.</p>
<p>Tardigrades are <a href="https://www.livescience.com/57985-tardigrade-facts.html">odd little creatures</a>. Measuring up to about half a millimetre long, they have four pairs of stubby legs and a front-end that even the fondest parent couldn’t describe as beautiful. Striking, or distinctive, are my adjectives of choice. Moon-faced would be appropriate, given the context of the story – with a rounded, sucker-like structure in the centre that can project outwards, revealing a set of dangerous-looking sharp teeth. </p>
<p>They’re often called “water bears” but the images of tardigrades that I have seen remind me of a slightly over-inflated blimp, one of those large balloons that float overhead at carnivals. The legs stick out at a slight angle, as if they are too swollen to stand upright. And that is probably the clue as to why it is extremely unlikely that the creatures will survive indefinitely on the moon.</p>
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<img alt="" src="https://images.theconversation.com/files/287345/original/file-20190808-144868-1dp7qa3.jpg?ixlib=rb-1.1.0&rect=474%2C0%2C3610%2C2392&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/287345/original/file-20190808-144868-1dp7qa3.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=200&fit=crop&dpr=1 600w, https://images.theconversation.com/files/287345/original/file-20190808-144868-1dp7qa3.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=200&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/287345/original/file-20190808-144868-1dp7qa3.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=200&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/287345/original/file-20190808-144868-1dp7qa3.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=251&fit=crop&dpr=1 754w, https://images.theconversation.com/files/287345/original/file-20190808-144868-1dp7qa3.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=251&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/287345/original/file-20190808-144868-1dp7qa3.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=251&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
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<span class="caption">Tardigrades in space.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-illustration/tardigrade-vacuum-open-space-water-bear-726719797?src=cjaqEapOnY5_mpZ177xWvA-1-5">Dotted Yeti/Shutterstock</a></span>
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<p>Tardigrades can survive extremes of temperature and pressure, including the frigid vacuum <a href="https://www.cell.com/current-biology/fulltext/S0960-9822(08)00805-1?_returnURL=https%3A%2F%2Flinkinghub.elsevier.com%2Fretrieve%2Fpii%2FS0960982208008051%3Fshowall%3Dtrue">of space</a>. They don’t seem to mind being <a href="https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0064793">exposed to radiation</a> and are all-round tough little creatures. When dehydrated, they roll up into a <a href="https://www.cell.com/biophysj/fulltext/S0006-3495(16)33630-X">spore-like state</a> that slows down their metabolic rate by about a hundred-fold, enabling them to survive for potentially <a href="https://zslpublications.onlinelibrary.wiley.com/doi/abs/10.1017/S095283690200078X">over 100 years</a>. </p>
<p>But to live their life to the fullest requires water. It’s where they get their oxygen and food, typically colonising clumps of algae or burrowing into sediment to ingest nutrients from the fluid of other living creatures, even other tardigrades. So while the tardigrades will technically stay alive on the moon for some length of time in their rolled-up state, unless they are rescued, rehydrated and refuelled, they will eventually perish.</p>
<h2>Interplanetary pollution</h2>
<p>I’m not concerned about polluting the moon with organisms that might reanimate. My concern is about polluting the moon, full stop. There is already a fairly sizeable <a href="https://www.theatlantic.com/technology/archive/2012/12/the-trash-weve-left-on-the-moon/266465/">amount of debris</a> from redundant spacecraft and litter left behind by astronauts. As more missions are planned to the moon, eventually with human passengers and perhaps even settlements, we must learn to clean up as we go along. Otherwise, we are going to have the sort of crisis that we are seeing on Earth with the outcry about environmental damage <a href="https://theconversation.com/uk/topics/plastic-pollution-52714">from plastics</a>. </p>
<p>There is, though, another question to consider. What if the spacecraft had crashed as it approached Mars rather than the moon? The planet has had a poor record for successful landings, although it is much improved in the past decade. Would the tardigrades have survived atmospheric entry? Even though the atmosphere of Mars is thin, it still provides sufficient resistance to cause serious damage to the outer shell of an entry vehicle.</p>
<p>If they had survived, would they ultimately be any more successfully on Mars than on the moon? We know there is plenty of ice below the immediate surface across much of the planet. Would an impacting spacecraft transfer sufficient energy to melt a local region of ice? Could that meltwater survive without sublimating away or refreezing for long enough that the tardigrades rehydrate and wake up?</p>
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<img alt="" src="https://images.theconversation.com/files/287348/original/file-20190808-144878-1qq5a3.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/287348/original/file-20190808-144878-1qq5a3.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=601&fit=crop&dpr=1 600w, https://images.theconversation.com/files/287348/original/file-20190808-144878-1qq5a3.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=601&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/287348/original/file-20190808-144878-1qq5a3.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=601&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/287348/original/file-20190808-144878-1qq5a3.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=755&fit=crop&dpr=1 754w, https://images.theconversation.com/files/287348/original/file-20190808-144878-1qq5a3.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=755&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/287348/original/file-20190808-144878-1qq5a3.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=755&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
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<span class="caption">The surface of Mars should be kept pristine.</span>
<span class="attribution"><a class="source" href="https://www.nasa.gov/multimedia/imagegallery/image_feature_645.html">NASA</a></span>
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<p>I have no idea, but let’s speculate that the answer to the two questions is “yes”, and that following a crash, a flock (herd? shoal? pack?) of tardigrades reactivates. What happens next? As detailed above, tardigrades need water to survive, not just to rehydrate them. They live on fluids derived from other living beings. And, as far as we know, there are no <a href="https://theconversation.com/uk/topics/life-on-mars-6975">living beings on Mars</a>. </p>
<p>But we still keep sending spacecraft to look for life. Sending a cargo of tardigrades to Mars would be irresponsible, even if we don’t believe they would survive. Irresponsible because Mars has the potential for life. Restricted life, for sure, but we have no right to endanger that life. And we have a responsibility to maintain Mars as close to pristine as possible, exploring it with care.</p>
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<p>That is why space agencies take such stringent precautions about spacecraft construction. The rooms in which the craft are built are <a href="https://www.wired.com/story/inside-the-cleanroom-where-nasas-new-mars-lander-waits-to-launch/">cleaner and more sterile</a> than any operating theatre. They take every precaution to ensure that no terrestrial life is transferred to Mars.</p>
<p>NASA and ESA are currently planning a <a href="https://www.space.com/nasa-mars-sample-return-mission-2026.html">mission to return</a> samples from Mars to Earth. And precautions about the possibility of returning Martian life to Earth with the rocks are central to the design and build of the spacecraft.</p>
<p>Last week, we had an asteroid <a href="https://www.technologyreview.com/f/614027/a-huge-asteroid-flew-very-close-to-earth-last-week-how-did-we-miss-it/">passing close to the Earth</a>. Next week, maybe it will be killer bees. Or a plague of thieving magpies. But for now it is water bears on the moon. We should let them shrivel slowly into oblivion.</p><img src="https://counter.theconversation.com/content/121602/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Monica Grady is Professor of Planetary and Space Sciences at the Open University, and Research Fellow at the Natural History Museum, London. She receives funding from the STFC and the UK Space Agency. She is a Trustee of Lunar Mission One.</span></em></p>An Israeli spacecraft carrying tardigrades crashed into the moon. Whether they will survive is irrelevant.Monica Grady, Professor of Planetary and Space Sciences, The Open UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1157572019-05-26T13:52:17Z2019-05-26T13:52:17ZWe need new treaties to address the growing problem of space debris<figure><img src="https://images.theconversation.com/files/275012/original/file-20190516-69186-16aeej2.jpg?ixlib=rb-1.1.0&rect=0%2C0%2C4479%2C2620&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">There are tens of thousands of pieces of space debris orbiting the Earth, and the amount is growing.</span> <span class="attribution"><span class="source">Shutterstock</span></span></figcaption></figure><p><a href="https://earthobservatory.nasa.gov/images/40173/space-debris">Space debris</a> represents the spread of our <a href="https://www.britannica.com/topic/scorched-earth-policy">scorched-earth habits</a> into space. Earth and the orbital space around it are a global commons to which we have been laying waste. And what’s worse, we appear powerless to prevent ourselves. </p>
<p>Since the dawn of the space age in 1957, our spacecraft have been jettisoning bits and pieces both deliberately (like launch shrouds) and inadvertently (like exploding fuel tanks). Then, to add insult to injury, dying spacecraft, following their last gasp, <a href="http://DOI.org/10.1126/science.1121337">are left in orbit as useless relics</a>. </p>
<h2>Space flotsam</h2>
<p>There are 15,888 pieces of debris larger than 10 centimetres in size, including some 2,000 pieces in or intersecting geostationary orbit, <a href="https://room.eu.com/article/urbocop/saving-planet-earth">the rest being dominantly in the polar orbital band at 800-1,000 kilometres in altitude</a>. Smaller sizes are even more plentiful — it’s estimated there are 500,000 pieces one centimetre in size, and 100 million pieces that are a millimetre in size, all rattling along at orbital speeds of eight to 12 kilometres a second (compared to a rifle bullet travelling at approximately one kilometre a second). </p>
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<figcaption><span class="caption">NASA animation showing the movement of man-made objects in orbit.</span></figcaption>
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<p>It’s a small wonder no astronauts have been seriously hurt yet. But spacecraft have: Cerise was the first documented case of a satellite being struck by debris in 1996. Since then, the situation has worsened. </p>
<p>In 2007, the Chinese, in a fit of muscle-flexing bravado, <a href="https://www.space.com/3415-china-anti-satellite-test-worrisome-debris-cloud-circles-earth.html">fired an anti-satellite missile at their defunct Fengyun-1C satellite</a> at 860-kilometre altitude, creating a shower of 2,400 debris pieces larger than 10 centimetres, and 35,000 smaller pieces. This increased the total debris population by 30 per cent. </p>
<p>In 2009, <a href="https://www.nytimes.com/2009/02/12/science/space/12satellite.html">a defunct Russian Cosmos satellite accidentally collided with an operational Iridium satellite</a> at 790-kilometre altitude, generating two clouds of debris comprising 598 fragments from the Iridium satellite and 1,603 fragments from the Cosmos satellite. </p>
<h2>Avoidance manouevres</h2>
<p>The International Space Station has to be manoeuvred around twice a year to avoid incoming debris. If we do nothing, the debris problem will worsen until <a href="https://doi.org/10.1029/JA083iA06p02637">the Kessler Syndrome limit is surpassed</a>. When this happens, debris will become self-perpetuating, creating an exponentially growing ring of projectiles around Earth, effectively entombing us and our planet for centuries to come. Attempts to curtail the growth of debris to date have been to no avail. </p>
<p><a href="http://www.unoosa.org/oosa/en/ourwork/topics/space-debris/index.html">United Nations recommendations</a> to boost ailing and dying satellites into so-called graveyard or decaying orbits have either been ignored or are ineffective. </p>
<p>Even more ominously, there’s expected to be large satellite operations launched in the near future to provide global services. Elon Musk’s space transportation company SpaceX <a href="https://www.businessinsider.com/spacex-starlink-satellite-internet-how-it-works-2019-5">envisages a constellation of 12,000 satellites</a>. The prospects for the future look bleak and we are falling headlong towards entombment of our deteriorating planet. </p>
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<img alt="" src="https://images.theconversation.com/files/276484/original/file-20190526-187172-92secp.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/276484/original/file-20190526-187172-92secp.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=422&fit=crop&dpr=1 600w, https://images.theconversation.com/files/276484/original/file-20190526-187172-92secp.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=422&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/276484/original/file-20190526-187172-92secp.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=422&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/276484/original/file-20190526-187172-92secp.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=531&fit=crop&dpr=1 754w, https://images.theconversation.com/files/276484/original/file-20190526-187172-92secp.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=531&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/276484/original/file-20190526-187172-92secp.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=531&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">A SpaceX Falcon Heavy rocket carrying a communication satellite lifts off from the Kennedy Space Center in Cape Canaveral, Fla., on April 11, 2019.</span>
<span class="attribution"><span class="source">(AP Photo/John Raoux)</span></span>
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<h2>Junk removal</h2>
<p>However, it’s not all doom and gloom. The worst effects of growing debris can be alleviated by removing up to 10 of the largest pieces of debris per year. Perhaps unsurprisingly, Europe — given its greener credentials than most other space-faring powers — has been taking the lead in developing active debris removal techniques. </p>
<p>The <a href="https://directory.eoportal.org/web/eoportal/satellite-missions/r/removedebris">European Union’s removeDEBRIS concept</a> adopted harpoons and nets to capture defunct satellites. However, these are essentially ballistic and uncontrolled, introducing complex dynamic problems. These techniques can also potentially cause more debris if they fracture or fragment spacecraft while trying ensnare them. </p>
<p><a href="https://www.esa.int/Our_Activities/Space_Safety/Clean_Space/ESA_s_e.Deorbit_debris_removal_mission_reborn_as_servicing_vehicle">The European Space Agency’s (ESA) e.Deorbit mission</a> adopted robotic arms to remove, in the first instance, the defunct eight-tonne <a href="https://www.esa.int/Our_Activities/Observing_the_Earth/Envisat/Mission_overview">Envisat satellite</a>. Unfortunately, ESA cancelled the mission due to a lack of a commercial market for space debris removal. Only if e.Deorbit is extended to incorporate commercial on-orbit servicing might it be revived at some unspecified time in the future.</p>
<h2>Human shortcomings</h2>
<p>This is a great shame as it leaves the most potentially dangerous source of debris — the huge Envisat — in orbit. Furthermore, it illustrates the failings of human nature. </p>
<p>Nothing will happen unless we see an opportunity for wealth or we are compelled to act. The only way for the latter is to impose a specific and new UN treaty built on top of the <a href="http://www.unoosa.org/oosa/en/ourwork/spacelaw/treaties/introouterspacetreaty.html">Outer Space Treaty</a> to join <a href="http://www.unoosa.org/oosa/en/ourwork/spacelaw/treaties.html">the other five derivative UN space treaties</a>. </p>
<p>This new treaty – let us call it the “Do Not Soil Your Own Doorstep and if You Must, Clean Up After Yourself” Treaty - must impose demands on space-faring nations to collectively clean up their pollution in orbit. </p>
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<figcaption><span class="caption">The Associated Press</span></figcaption>
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<p>UN Space Treaties have worked in the past. In 1977, the Russian Cosmos-954 reconnaissance satellite, carrying 50 kilograms of uranium-235, accidentally re-entered Earth’s atmosphere without ejecting its nuclear reactor into a safe orbit as intended. Radioactive debris was scattered over a 600-kilometre track in northern Canada, and was cleaned up by the Canadians with American assistance. The <a href="http://www.unoosa.org/oosa/en/ourwork/spacelaw/treaties/introliability-convention.html">UN Space Liability Convention</a> was successfully invoked — for the first and only time — to persuade Russia to foot the majority of the bill. </p>
<p>Likewise, we need a new treaty to coerce us to act to clean up space debris. Without some form of coercion, the problem will grow until we are entombed by an impenetrable layer of space junk.</p><img src="https://counter.theconversation.com/content/115757/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Alex Ellery receives funding from National Science & Engineering Research Council and the Canadian Space Agency. </span></em></p>There needs to be an international approach regarding the management and disposal of space junk.Alex Ellery, Associate Professor, Canada Research Chair in Space Robotics and Space Technology, Carleton UniversityLicensed as Creative Commons – attribution, no derivatives.