tag:theconversation.com,2011:/id/topics/water-on-mars-20947/articlesWater on Mars – The Conversation2019-09-05T05:01:59Ztag:theconversation.com,2011:article/1228572019-09-05T05:01:59Z2019-09-05T05:01:59ZTiny specks in space could be the key to finding martian life<figure><img src="https://images.theconversation.com/files/291046/original/file-20190905-175705-19z1try.jpg?ixlib=rb-1.1.0&rect=30%2C17%2C2845%2C1780&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Much of Mars's surface is covered by fine-grained materials that hide the bedrock. The above bedrock is mostly exposed and it is in these areas that micrometeorites likely to accumulate.</span> <span class="attribution"><span class="source">NASA/JPL-Caltech/Univ. of Arizona</span></span></figcaption></figure><p>Next year, both NASA and the European Space Agency (ESA) will send new rovers to Mars to hunt for evidence of past life.</p>
<p>As previous missions have discovered, Mars had a <a href="https://doi.org/10.1146/annurev-earth-060115-012355">warmer and wetter past</a>, featuring conditions that could probably sustain life. Current satellites orbiting Mars also reveal there are many places where water was once present on the surface. </p>
<p>The difficulty in hunting for life lies not in finding where there was water, but in identifying where the essential nutrients for life coincided with water. </p>
<h2>Micrometeorites mean potential life</h2>
<p>For life to move into a new environment and survive, it needs essential nutrients such as carbon, hydrogen, nitrogen, oxygen, phosphorus, and sulfur (together known as <a href="https://en.wikipedia.org/wiki/CHON">CHNOPS</a>), plus other trace elements. It also needs to acquire energy from the environment. Some of Earth’s earliest life forms gained energy by oxidising minerals.</p>
<p>Mars’s crust is mostly made of intrusive and volcanic basalt (the same rock that forms from Hawaii’s lavas) which is not particularly nutrient-rich. However, meteorites and micrometeorites are known to continuously provide essential nutrients to the surfaces of planets. </p>
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Read more:
<a href="https://theconversation.com/hope-springs-signs-of-life-could-be-waiting-for-us-on-mars-11800">Hope springs: signs of life could be waiting for us on Mars</a>
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<p><a href="https://doi.org/10.1029/2019JE006005">Our team investigated</a> how much cosmic dust (comet and asteroid dust) would survive atmospheric entry to Mars, and where it would accumulate on the surface as micrometeorites.</p>
<p>We <a href="https://doi.org/10.1111/maps.13360">modelled the heating and oxidation</a> effects of atmospheric entry to Mars and found most particles less than about 0.1-0.2mm in diameter would not melt, depending on their composition. In terms of materials accumulating on the martian surface, particles of this size are overwhelmingly more common than larger particles.</p>
<p>On Earth, about 100 times as much cosmic dust in this size range accumulates on the surface, when compared to meteorites larger than 4mm. This is despite extensive melting and evaporation during atmospheric entry to Earth. </p>
<h2>Evidence closer to home</h2>
<p>As part of our research, we used an analogue site on the Nullarbor Plain in South Australia (which, like Mars, has wind-modified sediment sitting on cracked bedrock) to examine whether wind causes micrometeorites to accumulate at predictable locations. </p>
<p>We found more than 1,600 micrometeorites from a variety of sample sites.</p>
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<img alt="" src="https://images.theconversation.com/files/291022/original/file-20190904-175682-fzkd33.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/291022/original/file-20190904-175682-fzkd33.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=471&fit=crop&dpr=1 600w, https://images.theconversation.com/files/291022/original/file-20190904-175682-fzkd33.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=471&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/291022/original/file-20190904-175682-fzkd33.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=471&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/291022/original/file-20190904-175682-fzkd33.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=591&fit=crop&dpr=1 754w, https://images.theconversation.com/files/291022/original/file-20190904-175682-fzkd33.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=591&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/291022/original/file-20190904-175682-fzkd33.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=591&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">Microscope image of a sectioned micrometeorite from the Nullarbor Plain, Australia. The bright sphere is iron-nickel metal, the grey minerals are iron oxides.</span>
<span class="attribution"><span class="source">Angus Rogers</span></span>
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<p>Our observations show that because many micrometeorites are denser than normal sand grains, they are likely to accumulate in bedrock cracks and on gravel-rich surfaces where lighter particles have been blown away. Our samples typically contained several hundred micrometeorites per kilogram. </p>
<p>Several factors added together indicate that micrometeorites should be much more abundant on Mars than on Earth. And this is expected to be true for most of Mars’s 4.5-billion-year history. </p>
<h2>Even martians need nutrients</h2>
<p>Unmelted and partially melted micrometeorites supply complex carbon compounds to the martian surface, which are the building blocks of life. They also supply the only source of reduced phosphorus through the mineral <a href="https://www.mindat.org/min-3582.html">schreibersite</a>, which has been shown to react with simple hydroxyl compounds to <a href="https://www.nature.com/articles/srep17198">form the precursors for life</a>. </p>
<p>Micrometeorites also provide other reduced minerals like sulfides and iron-nickel metal that can be exploited as an energy source by primitive microbes. Therefore, they provide both the essential nutrients and an energy source that can allow existing microbes to migrate and persist. </p>
<h2>Mars 2020</h2>
<p>Many scientists believe life on Earth may have started around <a href="https://en.wikipedia.org/wiki/Hydrothermal_vent">undersea geothermal vents</a> or in volcanic hot springs like those at <a href="https://en.wikipedia.org/wiki/Geothermal_areas_of_Yellowstone">Yellowstone</a> or <a href="https://en.wikipedia.org/wiki/Waiotapu">Rotorua</a>. Beneath these, water circulates through the hot crust, dissolving nutrients from the rocks and carrying them upwards to the vents, where there are dramatic changes in temperature and chemistry. </p>
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Read more:
<a href="https://theconversation.com/evidence-of-ancient-life-in-hot-springs-on-earth-could-point-to-fossil-life-on-mars-77388">Evidence of ancient life in hot springs on Earth could point to fossil life on Mars</a>
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<p>This creates a large range of niche environments, some of which have the ideal combination of water, temperate conditions and chemistry for life.</p>
<p>The expired Spirit rover found evidence of an <a href="https://www.nasa.gov/mission_pages/mer/mer-20070521.html">extinct volcanic spring on Mars</a> and more have been inferred from orbital observations. These volcanic springs were considered as a landing site for NASA’s Mars 2020 rover, but in the end Jezero Crater was chosen.</p>
<p>Jezero Crater has a combination of water-produced channels in a delta system that contains clay and carbonate minerals <a href="https://www.nature.com/articles/ngeo207">in sedimentary rocks</a>. These are ideal for <a href="https://www.nature.com/articles/srep05841">preserving</a> <a href="https://science.sciencemag.org/content/295/5555/657">geochemical signs</a> of life. Similarly, Oxia Planum has been chosen as the landing site for ESA’s ExoMars rover, which also contains clays in sedimentary deposits. </p>
<p>While neither Jezero Crater or Oxia Planum contain known volcanic springs, they are still water-rich environments where life may have existed on Mars. </p>
<p>Micrometeorites provide the nutrients that may have allowed life to migrate into and persist at these locations, and could even provide the ingredients for life to emerge away from Mars’s volcanic springs.</p>
<p>With plans in the works for 2020, we may soon be on the cusp of one of the greatest scientific breakthroughs of all time.</p><img src="https://counter.theconversation.com/content/122857/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Andrew Tomkins receives funding from the Australian Research Council. </span></em></p>It’s established Mars was once a planet with surface-level water. So with multiple MARS missions starting next year, the key to seeking out martian life may instead lie in the contents of its ‘dust’.Andrew Tomkins, Geologist, Monash UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1034052018-09-27T20:24:17Z2018-09-27T20:24:17ZA decade of commercial space travel – what’s next?<figure><img src="https://images.theconversation.com/files/237982/original/file-20180925-149970-hxpzhc.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">A Falcon 9 SpaceX heavy rocket lifts off from pad 39A at the Kennedy Space Center in Cape Canaveral, Fla., Feb. 6, 2018. </span> <span class="attribution"><a class="source" href="http://www.apimages.com/metadata/Index/SpaceX-New-Rocket-Launch/ed31c75793a5454cb8a9fbb1fa5360c3/162/0">AP Photo/ John Raoux </a></span></figcaption></figure><p>In many industries, a decade is barely enough time to cause dramatic change unless something disruptive comes along – a new technology, business model or service design. The space industry has recently been enjoying all three.</p>
<p>But 10 years ago, none of those innovations were guaranteed. In fact, on <a href="https://www.spacex.com/press/2012/12/19/spacex-successfully-launches-falcon-1-orbit">Sept. 28, 2008</a>, an entire company watched and hoped as their flagship product attempted a final launch after three failures. With cash running low, this was <a href="https://www.cnbc.com/2018/03/06/after-rocket-launch-elon-musk-tweets-about-the-spacex-of-10-years-ago.html">the last shot</a>. Over <a href="https://www.spaceflightnow.com/falcon9/001/f9guide.pdf">21,000 kilograms of kerosene and liquid oxygen</a> ignited and powered two booster stages off the launchpad.</p>
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<a href="https://images.theconversation.com/files/238165/original/file-20180926-48644-18z2hxd.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/238165/original/file-20180926-48644-18z2hxd.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/238165/original/file-20180926-48644-18z2hxd.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=784&fit=crop&dpr=1 600w, https://images.theconversation.com/files/238165/original/file-20180926-48644-18z2hxd.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=784&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/238165/original/file-20180926-48644-18z2hxd.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=784&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/238165/original/file-20180926-48644-18z2hxd.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=985&fit=crop&dpr=1 754w, https://images.theconversation.com/files/238165/original/file-20180926-48644-18z2hxd.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=985&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/238165/original/file-20180926-48644-18z2hxd.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=985&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">This first official picture of the Soviet satellite Sputnik I was issued in Moscow Oct. 9, 1957. The satellite measured 1 foot, 11 inches and weighed 184 pounds. The Space Age began as the Soviet Union launched Sputnik, the first man-made satellite, into orbit, on Oct. 4, 1957.</span>
<span class="attribution"><a class="source" href="http://www.apimages.com/metadata/Index/RUSSLAND-RAUMFAHRT-SPUTNIK-JAHRESTAG/3f928fd14c9046d18741411b2631d55e/10/0">AP Photo/TASS</a></span>
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<p>When that Falcon 1 rocket successfully reached orbit and the company secured a subsequent contract with NASA, SpaceX had survived its ‘startup dip’. That milestone – the first privately developed liquid-fueled rocket to reach orbit – ignited a new space industry that is changing our world, on this planet and beyond. What has happened in the intervening years, and what does it mean going forward?</p>
<p>While scientists are busy developing new technologies that address the countless technical problems of space, there is another segment of researchers, including myself, studying the business angle and the operations issues facing this new industry. <a href="https://doi.org/10.1111/deci.12312">In a recent paper</a>, my colleague <a href="http://www.anderson.ucla.edu/faculty-and-research/decisions-operations-and-technology-management/faculty/tang">Christopher Tang</a> and <a href="https://sc.edu/study/colleges_schools/moore/directory/wooten_joel.php">I</a> investigate the questions firms need to answer in order to create a sustainable space industry and make it possible for humans to establish extraterrestrial bases, mine asteroids and extend space travel – all while governments play an increasingly smaller role in funding space enterprises. We believe these business solutions may hold the less-glamorous key to unlocking the galaxy.</p>
<h2>The new global space industry</h2>
<p>When the Soviet Union launched their Sputnik program, putting a satellite in orbit in 1957, they kicked off a race to space fueled by international competition and Cold War fears. The Soviet Union and the United States played the primary roles, stringing together a series of “firsts” for the record books. The first chapter of the space race culminated with Neil Armstrong and Buzz Aldrin’s historic Apollo 11 moon landing which required massive public investment, on the order of <a href="https://babel.hathitrust.org/cgi/pt?id=mdp.39015084762734">US$25.4 billion</a>, almost $200 billion in today’s dollars.</p>
<p>Competition characterized this early portion of space history. Eventually, that evolved into collaboration, with the International Space Station being a stellar example, as governments worked toward shared goals. Now, we’ve entered a new phase – openness – with private, commercial companies leading the way. </p>
<p>The industry for spacecraft and satellite launches is becoming more commercialized, due, in part, to shrinking government budgets. According to a report from the investment firm <a href="https://spaceangels.com/post/space-investment-quarterly-q42017">Space Angels</a>, a record 120 venture capital firms invested over $3.9 billion in private space enterprises last year. The space industry is also becoming global, no longer dominated by the Cold War rivals, the United States and USSR. </p>
<p>In 2018 to date, there have been <a href="http://www.spacelaunchreport.com/log2018.html#log">72 orbital launches</a>, an average of two per week, from launch pads in China, Russia, India, Japan, French Guinea, New Zealand and the U.S. </p>
<p>The uptick in orbital launches of actual rockets as well as spacecraft launches, which includes satellites and probes launched from space, coincides with this openness over the past decade. </p>
<p>More governments, firms and even amateurs engage in various spacecraft launches than ever before. With more entities involved, innovation has flourished. As Roberson notes in <a href="https://www.digitaltrends.com/features/as-billionaires-ogle-mars-the-space-race-is-back-on/">Digital Trends</a>, “Private, commercial spaceflight. Even lunar exploration, mining, and colonization – it’s suddenly all on the table, making the race for space today more vital than it has felt in years.”</p>
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<img alt="" src="https://images.theconversation.com/files/237531/original/file-20180921-88806-oz153.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/237531/original/file-20180921-88806-oz153.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=272&fit=crop&dpr=1 600w, https://images.theconversation.com/files/237531/original/file-20180921-88806-oz153.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=272&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/237531/original/file-20180921-88806-oz153.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=272&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/237531/original/file-20180921-88806-oz153.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=342&fit=crop&dpr=1 754w, https://images.theconversation.com/files/237531/original/file-20180921-88806-oz153.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=342&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/237531/original/file-20180921-88806-oz153.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=342&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">Worldwide launches into space. Orbital launches include manned and unmanned spaceships launched into orbital flight from Earth. Spacecraft launches include all vehicles such as spaceships, satellites and probes launched from Earth or space.</span>
<span class="attribution"><span class="source">Wooten, J. and C. Tang (2018) Operations in space, Decision Sciences; Space Launch Report (Kyle 2017); Spacecraft Encyclopedia (Lafleur 2017)</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
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<p>One can see this vitality plainly in the news. On Sept. 21, Japan announced that two of its unmanned rovers, dubbed Minerva-II-1, had <a href="https://www.nature.com/articles/d41586-018-06808-0">landed on a small, distant asteroid</a>. For perspective, the scale of this landing is similar to hitting a 6-centimeter target from 20,000 kilometers away. And earlier this year, people around the world watched in awe as <a href="https://www.youtube.com/watch?v=A0FZIwabctw&feature=youtu.be">SpaceX’s Falcon Heavy rocket successfully launched</a> and – more impressively – returned its two boosters to a landing pad in a synchronized ballet of epic proportions. </p>
<h2>Challenges and opportunities</h2>
<p>Amidst the growth of capital, firms and knowledge, both researchers and practitioners must figure out how entities should manage their daily operations, organize their supply chain and develop sustainable operations in space. This is complicated by the <a href="https://www.wired.com/2016/02/space-is-cold-vast-and-deadly-humans-will-explore-it-anyway/">hurdles space poses</a>: distance, gravity, inhospitable environments and information scarcity.</p>
<p>One of the greatest challenges involves actually getting the things people want in space, into space. Manufacturing everything on Earth and then launching it with rockets is expensive and restrictive. A company called <a href="http://madeinspace.us">Made In Space</a> is taking a different approach by maintaining an additive manufacturing facility on the International Space Station and 3D printing right in space. Tools, spare parts and medical devices for the crew can all be created on demand. The benefits include more flexibility and better inventory management on the space station. In addition, certain products can be produced better in space than on Earth, such as pure optical fiber. </p>
<p>How should companies determine the value of manufacturing in space? Where should capacity be built and how should it be scaled up? The figure below breaks up the origin and destination of goods between Earth and space and arranges products into quadrants. Humans have mastered the lower left quadrant, made on Earth – for use on Earth. Moving clockwise from there, each quadrant introduces new challenges, for which we have less and less expertise. </p>
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<img alt="" src="https://images.theconversation.com/files/237533/original/file-20180921-129859-15r6len.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/237533/original/file-20180921-129859-15r6len.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=355&fit=crop&dpr=1 600w, https://images.theconversation.com/files/237533/original/file-20180921-129859-15r6len.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=355&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/237533/original/file-20180921-129859-15r6len.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=355&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/237533/original/file-20180921-129859-15r6len.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=447&fit=crop&dpr=1 754w, https://images.theconversation.com/files/237533/original/file-20180921-129859-15r6len.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=447&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/237533/original/file-20180921-129859-15r6len.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=447&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 framework of Earth-space operations.</span>
<span class="attribution"><span class="source">Wooten, J. and C. Tang (2018) Operations in Space, Decision Sciences</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
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<p>I first became interested in this particular problem as I listened to a panel of robotics experts discuss building a colony on Mars (in our third quadrant). You can’t build the structures on Earth and easily send them to Mars, so you must manufacture there. But putting human builders in that extreme environment is equally problematic. Essentially, an entirely new mode of production using robots and automation in an advance envoy may be required.</p>
<h2>Resources in space</h2>
<p>You might wonder where one gets the materials for manufacturing in space, but there is actually an <a href="http://doi.org/10.1080/14777620802391778">abundance of resources</a>: Metals for manufacturing can be found within asteroids, water for rocket fuel is frozen as ice on planets and moons, and rare elements like helium-3 for energy are embedded in the crust of the moon. If we brought that particular isotope back to Earth, we could <a href="https://www.popularmechanics.com/science/energy/a27961/mit-nuclear-fusion-experiment-increases-efficiency/">eliminate our dependence on fossil fuels</a>.</p>
<p>As demonstrated by the recent Minerva-II-1 asteroid landing, people are acquiring the technical know-how to locate and navigate to these materials. But extraction and transport are open questions. </p>
<p>How do these cases change the economics in the space industry? Already, companies like <a href="https://www.planetaryresources.com/">Planetary Resources</a>, <a href="http://www.moonexpress.com/">Moon Express</a>, <a href="http://deepspaceindustries.com/">Deep Space Industries</a>, and <a href="http://www.asterank.com/">Asterank</a> are organizing to address these opportunities. And scholars are beginning to outline <a href="http://doi.org/10.1080/14777620802391778">how to navigate questions of property rights, exploitation and partnerships</a>.</p>
<h2>Threats from space junk</h2>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/238365/original/file-20180927-48665-1698izu.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/238365/original/file-20180927-48665-1698izu.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=480&fit=crop&dpr=1 600w, https://images.theconversation.com/files/238365/original/file-20180927-48665-1698izu.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=480&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/238365/original/file-20180927-48665-1698izu.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=480&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/238365/original/file-20180927-48665-1698izu.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=603&fit=crop&dpr=1 754w, https://images.theconversation.com/files/238365/original/file-20180927-48665-1698izu.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=603&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/238365/original/file-20180927-48665-1698izu.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">
<figcaption>
<span class="caption">A computer-generated image of objects in Earth orbit that are currently being tracked. Approximately 95 percent of the objects in this illustration are orbital debris – not functional satellites. The dots represent the current location of each item. The orbital debris dots are scaled according to the image size of the graphic to optimize their visibility and are not scaled to Earth.</span>
<span class="attribution"><a class="source" href="https://commons.wikimedia.org/wiki/File:Debris-GEO1280.jpg">NASA</a></span>
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<p>The movie “Gravity” opens with a Russian satellite exploding, which sets off a chain reaction of destruction thanks to debris hitting a space shuttle, the Hubble telescope, and part of the International Space Station. The sequence, while not perfectly plausible as written, is a very real phenomenon. In fact, in 2013, a Russian satellite disintegrated when it was hit with fragments from a Chinese satellite that exploded in 2007. Known as the <a href="http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.394.6767&rep=rep1&type=pdf">Kessler effect</a>, <a href="https://doi.org/10.1016/j.spacepol.2012.06.004">the danger from the 500,000-plus pieces of space debris</a> has already gotten some attention in public policy circles. How should one prevent, reduce or mitigate this risk? Quantifying the environmental impact of the space industry and addressing sustainable operations is still to come. </p>
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<img alt="" src="https://images.theconversation.com/files/238203/original/file-20180926-48656-11og1iw.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/238203/original/file-20180926-48656-11og1iw.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=476&fit=crop&dpr=1 600w, https://images.theconversation.com/files/238203/original/file-20180926-48656-11og1iw.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=476&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/238203/original/file-20180926-48656-11og1iw.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=476&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/238203/original/file-20180926-48656-11og1iw.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=599&fit=crop&dpr=1 754w, https://images.theconversation.com/files/238203/original/file-20180926-48656-11og1iw.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=599&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/238203/original/file-20180926-48656-11og1iw.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=599&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">NASA scientist Mark Matney is seen through a fist-sized hole in a 3-inch thick piece of aluminum at Johnson Space Center’s orbital debris program lab. The hole was created by a thumb-size piece of material hitting the metal at very high speed simulating possible damage from space junk.</span>
<span class="attribution"><a class="source" href="http://www.apimages.com/metadata/Index/AP-A-TX-USA-SPACE-JUNK/9cb2de663cb84bf29dc55064be46126d/13/0">AP Photo/Pat Sullivan</a></span>
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<h2>What’s next?</h2>
<p>It’s true that space is becoming just another place to do business. There are companies that will handle the logistics of getting your destined-for-space module on board a rocket; there are companies that will fly those rockets to the International Space Station; and there are others that can make a replacement part once there. </p>
<p>What comes next? In one sense, it’s anybody’s guess, but all signs point to this new industry forging ahead. A new breakthrough could alter the speed, but the course seems set: exploring farther away from home, whether that’s the moon, asteroids or Mars. It’s hard to believe that 10 years ago, SpaceX launches were yet to be successful. Today, a vibrant private sector consists of scores of companies working on everything from commercial spacecraft and rocket propulsion to space mining and food production. The next step is working to solidify the business practices and mature the industry.</p>
<p>Standing in a large hall at the University of Pittsburgh as part of the <a href="https://whitehousefrontiers.pitt.edu/">White House Frontiers Conference</a>, I see the future. Wrapped around my head are state-of-the-art virtual reality goggles. I’m looking at the surface of Mars. Every detail is immediate and crisp. This is not just a video game or an aimless exercise. The scientific community has poured resources into such efforts because exploration is preceded by information. And who knows, maybe 10 years from now, someone will be standing on the actual surface of Mars.</p><img src="https://counter.theconversation.com/content/103405/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Joel Wooten 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>It has been 10 years since Elon Musk’s SpaceX launched the commercial space age. What hurdles must be overcome before private companies begin exploring, colonizing and mining other planets?Joel Wooten, Assistant Professor of Management Science, University of South CarolinaLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/999432018-07-26T05:39:42Z2018-07-26T05:39:42ZHow to grow crops on Mars if we are to live on the red planet<figure><img src="https://images.theconversation.com/files/229365/original/file-20180726-106502-1nt78ux.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">We can create the right kind of food plants to survive on Mars.</span> <span class="attribution"><span class="source">Shutterstock/SergeyDV</span></span></figcaption></figure><p>Preparations are <a href="https://www.nasa.gov/content/journey-to-mars-overview">already underway</a> for <a href="https://theconversation.com/the-new-space-race-why-we-need-a-human-mission-to-mars-73757">missions</a> that will land humans on Mars in a decade or so. But what would people eat if these missions eventually lead to the permanent colonisation of the red planet?</p>
<p>Once (if) humans do make it to Mars, a major challenge for any colony will be to generate a stable supply of food. The enormous costs of launching and resupplying resources from Earth will make that impractical.</p>
<p>Humans on Mars will need to move away from complete reliance on shipped cargo, and achieve a high level of self-sufficient and sustainable agriculture.</p>
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Read more:
<a href="https://theconversation.com/discovered-a-huge-liquid-water-lake-beneath-the-southern-pole-of-mars-100523">Discovered: a huge liquid water lake beneath the southern pole of Mars</a>
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<p>The <a href="http://science.sciencemag.org/content/early/2018/07/24/science.aar7268">recent discovery</a> of liquid water on Mars – which adds new information to the question of whether we will find life on the planet – does raise the possibility of using such supplies to help grow food.</p>
<p>But water is only one of many things we will need if we’re to grow enough food on Mars.</p>
<h2>What sort of food?</h2>
<p>Previous work has suggested the use of <a href="http://rsif.royalsocietypublishing.org/content/12/102/20140715">microbes</a> as a source of food on Mars. The use of <a href="https://www.nasa.gov/feature/lunar-martian-greenhouses-designed-to-mimic-those-on-earth">hydroponic greenhouses</a> and controlled environmental systems, similar to <a href="https://www.nasa.gov/mission_pages/station/research/10-074.html">one being tested</a> onboard the International Space Station to grow crops, is another option.</p>
<p><a href="https://doi.org/10.3390/genes9070348">This month</a>, in the journal Genes, we provide a new perspective based on the use of advanced synthetic biology to improve the potential performance of plant life on Mars.</p>
<p>Synthetic biology is a fast-growing field. It combines principles from engineering, DNA science, and computer science (among many other disciplines) to impart new and improved functions to living organisms.</p>
<p>Not only can we read DNA, but we can also design biological systems, test them, and even engineer whole organisms. <a href="http://syntheticyeast.org/sc2-0/introduction/">Yeast</a> is just one example of an industrial workhorse microbe whose whole genome is currently being re-engineered by an international consortium.</p>
<p>The technology has progressed so far that precision genetic engineering and automation can now be merged into automated robotic facilities, known as biofoundries.</p>
<p>These biofoundries can test millions of DNA designs in parallel to find the organisms with the qualities that we are looking for.</p>
<h2>Mars: Earth-like but not Earth</h2>
<p>Although Mars is the most Earth-like of our neighbouring planets, Mars and Earth differ in many ways.</p>
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Read more:
<a href="https://theconversation.com/dear-diary-the-sun-never-set-on-the-arctic-mars-simulation-84597">Dear diary: the Sun never set on the Arctic Mars simulation</a>
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<p>The gravity on Mars is around a third of that on Earth. Mars receives about half of the sunlight we get on Earth, but much higher levels of harmful ultraviolet (UV) and cosmic rays. The surface temperature of Mars is about -60°C and it has a thin atmosphere primarily made of carbon dioxide.</p>
<p>Unlike Earth’s soil, which is humid and rich in nutrients and microorganisms that support plant growth, Mars is covered with <a href="https://www.britannica.com/science/regolith">regolith</a>. This is an arid material that contains <a href="https://www.space.com/37402-mars-life-soil-toxic-perchlorates-radiation.html">perchlorate chemicals</a> that are toxic to humans.</p>
<p>Also – despite the latest sub-surface lake find – water on Mars mostly exists in the form of ice, and the low atmospheric pressure of the planet makes liquid water boil at around 5°C.</p>
<p>Plants on Earth have evolved for hundreds of millions of years and are adapted to terrestrial conditions, but they will not grow well on Mars. </p>
<p>This means that substantial resources that would be scarce and priceless for humans on Mars, like liquid water and energy, would need to be allocated to achieve efficient farming by artificially creating optimal plant growth conditions.</p>
<h2>Adapting plants to Mars</h2>
<p>A more rational alternative is to use synthetic biology to develop crops specifically for Mars. This formidable challenge can be tackled and fast-tracked by building a plant-focused Mars biofoundry. </p>
<p>Such an automated facility would be capable of expediting the engineering of biological designs and testing of their performance under simulated Martian conditions.</p>
<p>With adequate funding and active international collaboration, such an advanced facility could improve many of the traits required for making crops thrive on Mars within a decade. </p>
<p>This includes improving <a href="https://www.britannica.com/science/photosynthesis">photosynthesis</a> and photoprotection (to help protect plants from sunlight and UV rays), as well as drought and cold tolerance in plants, and engineering high-yield functional crops. We also need to modify microbes to detoxify and improve the Martian soil quality.</p>
<p>These are all challenges that are within the capability of modern synthetic biology.</p>
<h2>Benefits for Earth</h2>
<p>Developing the next generation of crops required for sustaining humans on Mars would also have great benefits for people on Earth.</p>
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Read more:
<a href="https://theconversation.com/before-we-colonise-mars-lets-look-to-our-problems-on-earth-87770">Before we colonise Mars, let's look to our problems on Earth</a>
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<p>The growing global population is <a href="https://theconversation.com/the-future-of-food-growing-more-with-the-same-land-35559">increasing the demand for food</a>. To meet this demand we must increase agricultural productivity, but we have to do so without negatively impacting our environment.</p>
<p>The best way to achieve these goals would be to improve the crops that are already widely used. Setting up facilities such as the proposed Mars Biofoundry would bring immense benefit to the turnaround time of plant research with implications for food security and environmental protection.</p>
<p>So ultimately, the main beneficiary of efforts to develop crops for Mars would be Earth.</p><img src="https://counter.theconversation.com/content/99943/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Briardo Llorente receives funding from the CSIRO Synthetic Biology Future Science Platform and Macquarie University. </span></em></p>If humans are to live on Mars they will need a stable supply of food. Earth plants are not suited to the Mars climate but we can engineer plants that are.Briardo Llorente, CSIRO Synthetic Biology Future Science Fellow, Macquarie UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/837282017-09-15T00:38:20Z2017-09-15T00:38:20ZIce mined on Mars could provide water for humans exploring space<figure><img src="https://images.theconversation.com/files/185582/original/file-20170912-2967-17bq0ii.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">There is water on Mars - but it's buried, and frozen. </span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/martian-sunset-mars-planet-red-landscape-591994049?src=yEGsm8lOHk0TC_yGCNfwhg-1-33">from www.shutterstock.com </a></span></figcaption></figure><p>As humans spread out across the Earth, the locations of new colonies were driven by the accessibility of resources: not only food and water, but also arable land, forests and minerals. </p>
<p>Access to such resources remains important as the economy moves into space. Here, water has emerged as the pre-eminent resource to exploit first. </p>
<p>The question then becomes, from where will we extract the water? Along with the <a href="http://science.sciencemag.org/content/330/6003/463">Moon</a> and <a href="http://www.uapress.arizona.edu/onlinebks/ResourcesNearEarthSpace/resources01.pdf">near Earth asteroids</a> as potential sources, Mars is an <a href="http://onlinelibrary.wiley.com/doi/10.1029/2008GL036379/full">important candidate</a>. </p>
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Read more:
<a href="https://theconversation.com/space-mining-is-closer-than-you-think-and-the-prospects-are-great-45707">Space mining is closer than you think, and the prospects are great</a>
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<h2>Eyes on Mars</h2>
<p>Mars is the focus for human settlement in space, largely due to Elon Musk’s <a href="http://www.spacex.com/mars">Space X</a>, <a href="http://www.mars-one.com/">Mars One</a> and <a href="https://mars.nasa.gov/">NASA’s activities</a> in this regard. </p>
<p>The NASA human landing site selection committee proposed 47 potential sites for a <a href="https://www.nasa.gov/journeytomars/mars-exploration-zones">human occupied base on Mars</a>. They considered not only scientific regions of interest but also “resource regions of interest” – where there is accessible water. </p>
<p>A number of conditions need to be met for an exploration zone to be considered useful for prospecting for water. Water needs to be accessible, located near the surface, and of sufficient size and concentration to meet the user needs. </p>
<p>For operational reasons the Mars water site also needs to be located with a latitude less than 50°. This ruled out the previously identified large surface ice deposits in the high latitude polar regions of Mars.</p>
<h2>Buried ice</h2>
<p>The Protonilus - Deuteronilus Mensae region on Mars is located in the northern mid-latitudes of Mars (~8°E and 60°E 38N and 50°N). </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/185574/original/file-20170912-20832-ocnxrh.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/185574/original/file-20170912-20832-ocnxrh.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/185574/original/file-20170912-20832-ocnxrh.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=294&fit=crop&dpr=1 600w, https://images.theconversation.com/files/185574/original/file-20170912-20832-ocnxrh.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=294&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/185574/original/file-20170912-20832-ocnxrh.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=294&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/185574/original/file-20170912-20832-ocnxrh.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=369&fit=crop&dpr=1 754w, https://images.theconversation.com/files/185574/original/file-20170912-20832-ocnxrh.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=369&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/185574/original/file-20170912-20832-ocnxrh.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=369&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 flattened map of the surface of Mars shows the location (red box) of the buried ice deposits in the Deuteronilus-Protonilus Mensae region.</span>
<span class="attribution"><span class="source">MOLA – NASA/JPL</span>, <span class="license">Author provided</span></span>
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<p>This region is host to numerous land forms which <a href="http://onlinelibrary.wiley.com/doi/10.1029/2008GL036379/full">appear to contain</a> large buried ice deposits, hundreds of meters thick and several kilometres wide. </p>
<p>If the ice is preserved as we believe, these features would represent a significant resource easily capable of satisfying the requirements for a human base. It is for this reason that three exploration zones have been proposed in the region.</p>
<p>At the low pressures in the Martian atmosphere, and the temperatures in equatorial regions, ice can “sublime” directly from the solid to gas state (evaporation being the transition from water to gas). The features we are observing protect ice under a layer of debris. </p>
<p>Because of this, it is not possible to evaluate directly the quantity of ice present. Instead we must rely on data collected by orbital spacecraft to work out the geological properties and potential water resources available. </p>
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<img alt="" src="https://images.theconversation.com/files/185573/original/file-20170912-26996-1wefihj.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/185573/original/file-20170912-26996-1wefihj.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=464&fit=crop&dpr=1 600w, https://images.theconversation.com/files/185573/original/file-20170912-26996-1wefihj.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=464&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/185573/original/file-20170912-26996-1wefihj.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=464&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/185573/original/file-20170912-26996-1wefihj.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=583&fit=crop&dpr=1 754w, https://images.theconversation.com/files/185573/original/file-20170912-26996-1wefihj.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=583&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/185573/original/file-20170912-26996-1wefihj.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=583&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">Image of a buried ice deposit in the Protonilus Mensae region on Mars. These features are considered analogous to debris-covered glaciers on Earth.</span>
<span class="attribution"><span class="source">CTX-NASA/JPL</span>, <span class="license">Author provided</span></span>
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<p>If we were able to make measurements on the planet itself (as we can usually do on Earth), things would be much clearer. However, there have been no landed rover missions to this region of Mars, so we are reliant on remotely sensed data. </p>
<p>There is still a lot to be learned from data collected by satellites orbiting Mars. These give us high resolution imagery of the surface, along with insight into the geological properties of these features. </p>
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Read more:
<a href="https://theconversation.com/dear-diary-another-day-in-the-life-on-mars-75929">Dear diary: another day in the life on Mars</a>
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<p>We can make informed assessments about how much water there is, and where it is distributed, as well as about what lies over it (which will have to either be drilled through or excavated to reach the water). These interpretations can be used to guide future exploration activities, and assist equipment design and mine planning operations. </p>
<p>Rover missions could provide more certainty but planning such a mission will not occur until after site selection, and insight into the feasibility of mining ice deposits on Mars to support human missions to the Red Planet. </p>
<h2>Other mining in space</h2>
<p>It’s not only Mars which is being investigated as a potential source of water in space. The Moon with its supply of polar water ice is being considered as a potential resource to supply proposed lunar bases or propellant for Mars missions. The <a href="https://arc.aiaa.org/doi/abs/10.2514/6.2014-4378">Lunar Resource Prospector mission</a> set to launch in the early 2020s will help us better understand the resource potential of the Moon. </p>
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Read more:
<a href="https://theconversation.com/all-of-humanity-should-share-in-the-space-mining-boom-57740">All of humanity should share in the space mining boom</a>
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<p>Asteroid mining companies such as <a href="http://deepspaceindustries.com/">Deep Space Industries</a> and <a href="http://www.planetaryresources.com/#home-intro">Planetary Resources</a> are looking to exploit water stored in near Earth asteroids and are working towards exploratory missions in the near future. </p>
<p>There are a large number of technical issues that must be navigated before such an ambitious mining enterprise is considered low-risk enough to be feasible. These are challenging, but not insurmountable. A <a href="http://www.spaceresources.public.lu/en.html">significant international effort</a> is afoot to solve the problems with several companies, the major space agencies and the government of Luxembourg committed to the task.</p>
<p>Representatives from these stakeholder groups will be in Australia to discuss these issues at the <a href="http://www.acser.unsw.edu.au/oemf2017">Off-Earth Mining Forum</a> to be held in Sydney, September 20-21, 2017.</p><img src="https://counter.theconversation.com/content/83728/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Sophia Casanova is a PhD Candidate at the University of New South Wales. She is a recipient of the University Postgraduate Award. </span></em></p><p class="fine-print"><em><span>Andrew Dempster works for UNSW. He receives funding from the Australian Research Council. He is co-chair of the Forum mentioned in the article</span></em></p><p class="fine-print"><em><span>Serkan Saydam receives funding from Australian Research Council and ACARP, he is co-chair of Off Earth Mining Forum mentioned in the article. </span></em></p>Space exploration is exciting - but there are barriers for humans hoping to visit and even stay on planets. Buried ice on Mars could be a water source for interplanetary visits of the future.Sophia Casanova, PhD Candidate - Mining Engineering, UNSW SydneyAndrew Dempster, Director, Australian Centre for Space Engineering Research; Professor, School of Electrical Engineering and Telecommunications, UNSW SydneyLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/571642016-04-04T12:17:24Z2016-04-04T12:17:24ZHow exploring Mars could help us fight climate change on Earth<figure><img src="https://images.theconversation.com/files/117171/original/image-20160402-6809-15zd5cq.jpg?ixlib=rb-1.1.0&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>The surface of Mars is a cold desert. Scars in the landscape point to a history of flowing rivers, standing lakes and possibly even planetary oceans. Yet the <a href="http://nssdc.gsfc.nasa.gov/planetary/factsheet/marsfact.html">current Martian atmosphere</a> has a density that’s around 0.6% of Earth’s, making it far too thin to support liquid water – or life – on the barren surface. </p>
<p>At some point in the planet’s history, however, there must have been a thicker, denser atmosphere, probably dominated by carbon dioxide (CO<sub>2</sub>). And working out what happened to all that CO<sub>2</sub> could help us deal with the increasing amount of the gas in our own atmosphere, which is pushing us towards dangerous climate change.</p>
<p>So where did the Martian atmosphere go? A large amount was lost to space, stripped away <a href="https://www.youtube.com/watch?v=gX5JCYBZpcg">by the solar wind</a>. Some has been stored as CO<sub>2</sub> ice at the poles, where it remains today. But part of the atmosphere was transformed into carbonate minerals and preserved through the millennia. <a href="http://www.nasa.gov/mission_pages/mer/news/mer20100603.html">Using a combination</a> of satellites and rovers, as well as evidence from meteorites that have been ejected from Mars and landed on Earth, we are beginning to understand how this process of mineral carbonation can change an entire planet’s atmosphere.</p>
<p>Humanity has actually become very good at <a href="https://theconversation.com/explainer-what-is-carbon-capture-and-storage-16052">capturing</a> CO<sub>2</sub> from the atmosphere through a wide <a href="https://theconversation.com/explainer-what-is-carbon-capture-and-utilisation-19311">variety of techniques</a>. Once captured, the CO<sub>2</sub> is usually compressed into a dense liquid. The problem comes in storing this liquid safely and stably, over millions of years. One exciting new development is called “mineral carbon sequestration”. This is the process of transforming CO<sub>2</sub> gas into a stable mineral called carbonate.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/117299/original/image-20160404-27129-kn3ruo.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/117299/original/image-20160404-27129-kn3ruo.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/117299/original/image-20160404-27129-kn3ruo.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/117299/original/image-20160404-27129-kn3ruo.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/117299/original/image-20160404-27129-kn3ruo.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/117299/original/image-20160404-27129-kn3ruo.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/117299/original/image-20160404-27129-kn3ruo.jpg?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">
<figcaption>
<span class="caption">Filling the cracks.</span>
<span class="attribution"><span class="license">Author provided</span></span>
</figcaption>
</figure>
<h2>Turning CO<sub>2</sub> into rock</h2>
<p>How does CO<sub>2</sub> gas become solid rock? If CO<sub>2</sub> gas dissolves in water it produces a weak acid, called carbonic acid. When this acidic fluid comes into contact with rocks known as basalts and peridotites, which contain lots of the minerals olivine and pyroxene, they <a href="http://alliance.la.asu.edu/temporary/students/Phil/MineralCarbonation.pdf">release charged particles</a> of elements such as magnesium, iron and calcium into the fluid. </p>
<p>More chemical reactions between the rocks and carbonic fluid produce the solid, carbon-rich mineral carbonate, which fills cracks and pore spaces in the rocks. The carbon goes from being an atmospheric gas to a mineral deposit. During this process of alteration, the original rock minerals absorb huge amounts of water into their structure. This hydration causes the rocks to expand and crack, exposing fresh rocks that can also react with the water.</p>
<p>This process of mineral carbon sequestration happens naturally on Earth, particularly in ophiolites, pieces of oceanic crust that have been transported and pushed up onto continental plates. The natural reaction proceeds very slowly, over hundreds of thousands of years, and the carbon extracted from the atmosphere is an important sink for carbon ejected by <a href="https://www.whoi.edu/page.do?pid=97063&tid=7342&cid=86851">volcanic eruptions</a>.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/117291/original/image-20160404-27154-19jqyiq.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/117291/original/image-20160404-27154-19jqyiq.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=470&fit=crop&dpr=1 600w, https://images.theconversation.com/files/117291/original/image-20160404-27154-19jqyiq.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=470&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/117291/original/image-20160404-27154-19jqyiq.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=470&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/117291/original/image-20160404-27154-19jqyiq.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=590&fit=crop&dpr=1 754w, https://images.theconversation.com/files/117291/original/image-20160404-27154-19jqyiq.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=590&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/117291/original/image-20160404-27154-19jqyiq.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=590&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Iceland is experimenting with carbon mineralisation.</span>
<span class="attribution"><a class="source" href="https://www.flickr.com/photos/thinkgeoenergy/4473298115/">PROThinkGeoEnergy/Flickr</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
</figcaption>
</figure>
<p>But if we can artificially recreate this process, making it proceed at a faster rate, we can more safely store the CO<sub>2</sub> we remove from the atmosphere. This kind of mineral carbon storage geoengineering is now being experimented with at a number of pilot projects including <a href="http://www.or.is/en/projects/carbfix">Iceland</a>, <a href="https://str.llnl.gov/str/Johnson.html">Norway</a> and the <a href="http://www.pnl.gov/publications/abstracts.asp?report=300909">United States</a>.</p>
<p>Researchers in these countries have discovered that the reaction happens <a href="http://www.pnas.org/content/105/45/17295.full.pdf">much more quickly</a> if the fluid temperature is raised to around 185°C. This heated fluid is injected down a borehole to the desired rock formation, where it stays hot because of the natural warmth below the Earth’s surface and because the reaction itself produces heat.</p>
<p>However, many questions need answering before the technique can be carried out on a large enough scale to be useful against global climate change. Ideally, we will need many hundreds of carbon injection sites, such as <a href="http://www.nytimes.com/2015/02/10/science/burying-a-mountain-of-co2.html?_r=0">the CarbFix facility</a>, dotted across Earth’s vast basalt wilderness regions. The challenges include fully understanding the chemical reactions between the rock and water, learning how to deploy these reactions fast enough, and more accurately estimating how quickly the CO<sub>2</sub> will mineralise and the space it will take up.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/117288/original/image-20160404-27112-1676vbb.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/117288/original/image-20160404-27112-1676vbb.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=366&fit=crop&dpr=1 600w, https://images.theconversation.com/files/117288/original/image-20160404-27112-1676vbb.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=366&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/117288/original/image-20160404-27112-1676vbb.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=366&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/117288/original/image-20160404-27112-1676vbb.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=459&fit=crop&dpr=1 754w, https://images.theconversation.com/files/117288/original/image-20160404-27112-1676vbb.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=459&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/117288/original/image-20160404-27112-1676vbb.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=459&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Fighting climate change on another planet.</span>
<span class="attribution"><span class="source">NASA/JPL-Caltech/MSSS</span></span>
</figcaption>
</figure>
<h2>Mars’s loss, Earth’s gain</h2>
<p>This is where we can learn from Mars. There is a near-endless variety of ways that unpicking the chemical evolution of one planet might better inform geoengineering actions on our own. For example, understanding the long-term fate of Martian carbonates and how they interact with the atmosphere and hydrosphere, will teach us how effective this form of carbon storage might be on Earth.</p>
<p>Analysing the carbonates found on Mars, the way reactions have taken place, and how carbon concentrations have changed across the planet, may help us to better understand the process of mineral carbon sequestration. New carbonate types <a href="https://deepcarbon.net/feature/announcing-carbon-mineral-challenge-worldwide-hunt-new-carbon-minerals#.VwEdD_krK70">might be discovered</a> that provide clues about carbon-based minerals we think exist but haven’t yet been found on Earth.</p>
<p>The problem is there this is surprisingly little communication between Mars scientists and Earth climate change specialists. By combining the knowledge of these two groups, we may be able to control our global climate problems by using the planet’s rocky crust. Mars’ atmosphere loss may eventually become Earth’s climate change saviour.</p><img src="https://counter.theconversation.com/content/57164/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Adrienne Macartney receives funding from the UK Space Agency, and works in collaboration with the British Geological Survey. She is an SNP party member. This article does not represent the views of any public bodies.</span></em></p>Working out how Mars’s carbon dioxide was turned into rock could help with carbon capture efforts on our own planet.Adrienne Macartney, PhD researcher, School of Geographical and Earth Sciences, University of GlasgowLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/480742015-10-01T08:24:28Z2015-10-01T08:24:28ZHow close are we to actually becoming Martians?<p>Like any long-distance relationship, our love affair with Mars has had its ups and downs. The planet’s red tint made it a distinctive – but ominous – nighttime presence <a href="https://books.google.com/books/about/Martian_Metamorphoses.html?id=jz3eqRGuM0wC">to the ancients</a>, who gazed at it with the naked eye. Later we got closer views through telescopes, but the planet still remained a mystery, ripe for speculation. </p>
<p>A century ago, the American astronomer Percival Lowell <a href="http://www.space.com/13197-mars-canals-water-history-lowell.html">mistakenly interpreted</a> Martian surface features as canals that intelligent beings had built to distribute water across a dry world. This was just one example in a long history of imagining life on Mars, from H G Wells <a href="https://en.wikipedia.org/wiki/The_War_of_the_Worlds">portraying</a> Martians as bloodthirsty invaders of Earth, to <a href="https://www.edgarriceburroughs.com/?page_id=46">Edgar Rice Burroughs</a>, <a href="https://en.wikipedia.org/wiki/Kim_Stanley_Robinson">Kim Stanley Robinson</a> and others wondering how we could visit Mars and meet the Martians.</p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/96703/original/image-20150930-30970-1wigjs2.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/96703/original/image-20150930-30970-1wigjs2.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/96703/original/image-20150930-30970-1wigjs2.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=600&fit=crop&dpr=1 600w, https://images.theconversation.com/files/96703/original/image-20150930-30970-1wigjs2.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=600&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/96703/original/image-20150930-30970-1wigjs2.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=600&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/96703/original/image-20150930-30970-1wigjs2.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=754&fit=crop&dpr=1 754w, https://images.theconversation.com/files/96703/original/image-20150930-30970-1wigjs2.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=754&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/96703/original/image-20150930-30970-1wigjs2.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=754&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 red planet, as seen by the Hubble Space Telescope.</span>
<span class="attribution"><a class="source" href="http://hubblesite.org/newscenter/archive/releases/1999/07/image/b/">Jim Bell (Cornell University), Justin Maki (JPL), and Mike Wolff (Space Sciences Institute) and NASA</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
</figcaption>
</figure>
<p>The latest entry in this long tradition is the sci-fi flick <a href="http://www.foxmovies.com/movies/the-martian">The Martian</a>, to be released on October 2. Directed by Ridley Scott and based on Andy Weir’s <a href="http://andyweirauthor.com/books/the-martian-hc">self-published novel</a>, it tells the story of an astronaut (played by Matt Damon) stranded on Mars. Both book and movie <a href="http://www.space.com/30365-how-to-kill-or-save-a-martian-author-andy-weir-knows-video.html">try to be as true to the science as possible</a> – and, in fact, the science and the fiction around missions to Mars are rapidly converging.</p>
<p>NASA’s <a href="https://www.nasa.gov/mission_pages/msl/index.html">Curiosity rover</a> and other instruments have shown that Mars <a href="https://www.nasa.gov/press/2015/march/nasa-research-suggests-mars-once-had-more-water-than-earth-s-arctic-ocean/">once had oceans</a> of liquid water, a tantalizing hint that life was once present.</p>
<p>And now NASA has <a href="http://www.nasa.gov/press-release/nasa-confirms-evidence-that-liquid-water-flows-on-today-s-mars">just reported</a> the electrifying news that liquid water is flowing on Mars today. </p>
<p>This discovery increases the odds that there is currently life on Mars – picture microbes, not little green men – while heightening interest in NASA’s <a href="https://www.nasa.gov/content/nasas-journey-to-mars">proposal</a> to send astronauts there by the 2030s as the next great exploration of space and alien life. </p>
<p>So how close are we to actually sending people to Mars and having them survive on an inhospitable planet?</p>
<h2>First we have to get there</h2>
<p>Making it to Mars won’t be easy. It’s the next planet out from the sun, but a daunting <a href="http://www.space.com/24701-how-long-does-it-take-to-get-to-mars.html">140 million miles</a> away from us, on average – far beyond the Earth’s moon, which, at nearly 250,000 miles away, is the only other celestial body human beings have set foot on. </p>
<p>Nevertheless, <a href="http://www.nasa.gov/content/nasas-orion-flight-test-and-the-journey-to-mars">NASA</a> and several private <a href="http://www.space.com/23762-manned-mars-mission-ideas.html">ventures</a> believe that by further developing existing propulsion methods, they can send a manned spacecraft to Mars.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/96690/original/image-20150929-30967-myegq6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/96690/original/image-20150929-30967-myegq6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/96690/original/image-20150929-30967-myegq6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=398&fit=crop&dpr=1 600w, https://images.theconversation.com/files/96690/original/image-20150929-30967-myegq6.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=398&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/96690/original/image-20150929-30967-myegq6.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=398&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/96690/original/image-20150929-30967-myegq6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=500&fit=crop&dpr=1 754w, https://images.theconversation.com/files/96690/original/image-20150929-30967-myegq6.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=500&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/96690/original/image-20150929-30967-myegq6.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=500&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">It’s going to take the largest, most powerful rocket booster ever built to make it all the way to Mars. Tests are already under way.</span>
<span class="attribution"><a class="source" href="https://www.nasa.gov/content/test-firing-of-booster-for-nasas-new-rocket">Orbital ATK</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
</figcaption>
</figure>
<p>One NASA <a href="http://www.space.com/29562-nasa-manned-mars-mission-phobos.html">scenario</a> would, over several years, pre-position supplies on the Martian moon Phobos, shipped there by unmanned spacecraft; land four astronauts on Phobos after an eight-month trip from Earth; and ferry them and their supplies down to Mars for a 10-month stay, before returning the astronauts to Earth.</p>
<p>We know less, though, about how a long voyage inside a cramped metal box would affect crew health and morale. Extended time in space under essentially zero gravity has adverse effects, including loss of <a href="http://www.nasa.gov/home/hqnews/2012/aug/HQ_12-291_ISS_Bone_Density.html">bone density</a> and <a href="http://www.nasa.gov/mission_pages/station/research/experiments/245.html">muscle strength</a>, which astronauts experienced after months aboard the International Space Station (<a href="http://www.nasa.gov/mission_pages/station/main/index.html">ISS</a>). </p>
<p>There are psychological factors, too. ISS astronauts in Earth orbit can see and communicate with their home planet, and could reach it in an escape craft, if necessary. </p>
<p>For the isolated Mars team, home would be a distant dot in the sky; contact would be made difficult by the long time lag for radio signals. Even at the closest approach of Mars to the Earth, 36 million miles, nearly seven minutes would go by before anything said over a radio link could receive a response. </p>
<p>To cope with all this, the crew would have to be carefully screened and trained. NASA is now simulating the psychological and physiological effects of such a journey in an <a href="http://www.space.com/30425-yearlong-mock-mars-mission-begins.html">experiment</a> that is isolating six people for a year within a small structure in Hawaii. </p>
<h2>Surviving in an inhospitable Martian landscape</h2>
<p>These concerns would continue during the astronauts’ stay on Mars, which is a harsh world. With <a href="http://www.space.com/16907-what-is-the-temperature-of-mars.html">temperatures</a> that average -80 Fahrenheit (-62 Celsius) and can drop to -100F (-73C) at night, it is cold beyond anything we encounter on Earth; its thin atmosphere, mostly carbon dioxide (CO₂), is unbreathable and supports <a href="http://science.nasa.gov/science-news/science-at-nasa/2001/ast11oct_2/">huge dust storms</a>; it is subject to ultraviolet radiation from the sun that may be harmful; and its size and mass give it a gravitational pull that is only <a href="http://mars.nasa.gov/allaboutmars/extreme/quickfacts/">38% of the Earth’s</a> – which astronauts exploring the surface in heavy protective suits would welcome, but could also further exacerbate bone and muscle problems. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/96689/original/image-20150929-30999-vpcji.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/96689/original/image-20150929-30999-vpcji.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/96689/original/image-20150929-30999-vpcji.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=399&fit=crop&dpr=1 600w, https://images.theconversation.com/files/96689/original/image-20150929-30999-vpcji.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=399&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/96689/original/image-20150929-30999-vpcji.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=399&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/96689/original/image-20150929-30999-vpcji.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=502&fit=crop&dpr=1 754w, https://images.theconversation.com/files/96689/original/image-20150929-30999-vpcji.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=502&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/96689/original/image-20150929-30999-vpcji.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"></a>
<figcaption>
<span class="caption">Engineers and technicians are already testing the spacesuit astronauts will wear in the Orion spacecraft on trips to deep space, including Mars.</span>
<span class="attribution"><a class="source" href="https://www.nasa.gov/content/astronaut-spacesuit-testing-for-orion-spacecraft">NASA/Bill Stafford</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
</figcaption>
</figure>
<p>As the astronauts establish their base, NASA is planning to use Mars’ own resources to overcome some of these obstacles. </p>
<p>Fortunately, water and oxygen should be available. NASA had planned to try a form of mining to retrieve water existing just below the Martian surface, but the new finding of surface water may provide an easier solution for the astronauts. Mars also has considerable oxygen bound up in its atmospheric CO₂. In the <a href="http://mars.nasa.gov/mars2020/news/whatsnew/index.cfm?FuseAction=ShowNews&NewsID=1683">MOXIE</a> process (Mars Oxygen In situ resource utilization Experiment), electricity breaks up CO₂ molecules into carbon monoxide and breathable oxygen. NASA proposes to test this oxygen factory aboard a new Mars rover in 2020 and then scale it up for the manned mission. </p>
<p>There is also potential to <a href="http://nssdc.gsfc.nasa.gov/planetary/mars/marssurf.html">produce</a> the compound methane from Martian sources as rocket fuel for the return to Earth. The astronauts should be able to grow food, too, using techniques that recently allowed the ISS astronauts to <a href="http://www.nytimes.com/2015/08/11/science/growing-vegetables-in-space-nasa-astronauts-tweet-their-lunch.html?_r=0">taste the first lettuce grown in space</a>.</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/RqtAK-FBtXU?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">Harvesting and eating the first food grown in microgravity.</span></figcaption>
</figure>
<p>Without utilizing some of Mars’ raw materials, NASA would have to ship every scrap of what the astronauts would need: equipment, their habitation, food, water, oxygen and rocket fuel for the return trip. Every extra pound that has to be hauled up from Earth makes the project that much more difficult. “Living off the land” on Mars, though it might affect the local environment, would hugely improve the odds for success of the initial mission – and for eventual settlements there. </p>
<p>NASA will continue to learn about Mars and hone its planning over the next 15 years. Of course, there are formidable difficulties ahead; but it’s key that the effort does not require any major scientific breakthroughs, which, by their nature, are unpredictable. Instead, all the necessary elements depend on known science being applied via enhanced technology. </p>
<p>Yes, we’re closer to Mars than many may think. And a successful manned mission could be the signature human achievement of our century.</p><img src="https://counter.theconversation.com/content/48074/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Sidney Perkowitz 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>NASA has set a target date of 2030 for a manned mission to Mars. With no real scientific breakthroughs needed, success depends on developing the proper technology.Sidney Perkowitz, Emeritus Candler Professor of Physics, Emory UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/481822015-09-28T15:03:42Z2015-09-28T15:03:42ZNASA: streaks of salt on Mars mean flowing water, and raise new hopes of finding life<figure><img src="https://images.theconversation.com/files/96234/original/image-20150925-17725-1smuei0.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">The mysterious ephemeral dark streaks on Mars. </span> <span class="attribution"><a class="source" href="http://redplanet.asu.edu/?p=756">NASA/JPL-Caltech/UArizona</a></span></figcaption></figure><p>Salty streaks <a href="http://nature.com/articles/doi:10.1038/ngeo2546">have been discovered on Mars</a>, which could be a sign that salt water seeps to the surface in the summers. Scientists have previously observed dark streaks (see image above) on the planet’s slopes which are thought to have resulted from seeps of water wetting surface dust. Evidence of salts left behind in these streaks as the water dried up are the best evidence for this yet. The discovery is important – not least as it raises the tantalising prospect of a viable habitat for microbial life on Mars.</p>
<p>I have lost track of how many times water has been “discovered” on Mars. In this case, the researchers have detected hydrated salts rather than salty water itself. But the results, published in <a href="http://nature.com/articles/doi:10.1038/ngeo2546">Nature Geoscience</a>, are an important step to finding actual, liquid water. So how close are we? Let’s take a look at what we know so far and where the new findings fit in.</p>
<h2>Ice versus liquid water</h2>
<p>Back in the 18th century, <a href="http://www.bbc.co.uk/science/space/solarsystem/scientists/william_herschel">William Herschel</a> suggested that Mars’s polar caps, which even a small telescope can detect, were made of ice or snow – but he had no proof. It wasn’t until the 1950s that <a href="http://onlinelibrary.wiley.com/doi/10.1029/JC075i003p00510/pdf">data from telescopes fitted with spectrometers</a>, which analyse reflected sunlight, was interpreted as showing frozen water (water-ice). However, <a href="http://www.space.com/18787-mariner-4.html">the first spacecraft to Mars</a> found this difficult to confirm, as water-ice is in most places usually covered by ice made up of carbon dioxide.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/96236/original/image-20150925-17725-1k6o7rp.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/96236/original/image-20150925-17725-1k6o7rp.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=379&fit=crop&dpr=1 600w, https://images.theconversation.com/files/96236/original/image-20150925-17725-1k6o7rp.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=379&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/96236/original/image-20150925-17725-1k6o7rp.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=379&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/96236/original/image-20150925-17725-1k6o7rp.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=476&fit=crop&dpr=1 754w, https://images.theconversation.com/files/96236/original/image-20150925-17725-1k6o7rp.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=476&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/96236/original/image-20150925-17725-1k6o7rp.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=476&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Part of Nirgal Vallis, a valley on Mars first seen on this image by Mariner 9 in 1972. This image is 120km from side to side.</span>
<span class="attribution"><a class="source" href="http://www.nasa.gov/mission_pages/msl/multimedia/pia15090.html">NASA</a></span>
</figcaption>
</figure>
<p>In the 1970s attention turned to the much juicier topic of liquid water on Mars, with <a href="http://www.space.com/18439-mariner-9.html">the discovery by Mariner 9</a> of ancient river channels that must have been carved by flowing water. These channel systems were evidently very ancient (billions of years old), so although they showed an abundance of liquid water in the past they had no bearing on the occurrence of water at the present time.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/96240/original/image-20150925-17725-9mvhyw.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/96240/original/image-20150925-17725-9mvhyw.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=307&fit=crop&dpr=1 600w, https://images.theconversation.com/files/96240/original/image-20150925-17725-9mvhyw.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=307&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/96240/original/image-20150925-17725-9mvhyw.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=307&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/96240/original/image-20150925-17725-9mvhyw.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=385&fit=crop&dpr=1 754w, https://images.theconversation.com/files/96240/original/image-20150925-17725-9mvhyw.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=385&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/96240/original/image-20150925-17725-9mvhyw.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=385&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">‘Canals’ on Mars drawn by Percival Lowell in 1896.</span>
<span class="attribution"><a class="source" href="https://en.wikipedia.org/wiki/Percival_Lowell#/media/File:Lowell_Mars_channels.jpg">Percival Lowell/wikipedia</a></span>
</figcaption>
</figure>
<h2>Gullies & droplets</h2>
<p>Things became more interesting in 2000, with <a href="http://science.nasa.gov/science-news/science-at-nasa/2000/ast22jun_2/http://science.nasa.gov/science-news/science-at-nasa/2000/ast22jun_2/">the announcement</a> that high-resolution images from the <a href="http://www.msss.com/all_projects/mgs-mars-orbiter-camera.php">Mars Orbiter Camera</a> on board <a href="http://mars.nasa.gov/mgs/">Mars Global Surveyor</a> showed gullies several metres deep and hundreds of metres long running down the internal slopes of craters. </p>
<p>It was suggested that they were carved by water that had escaped from underground storage. Such small and sharp features had to be young. They could still have been thousands of years old but annual changes were soon noticed in a few gullies which appeared to suggest that they were <a href="http://science.nasa.gov/science-news/science-at-nasa/2000/ast22jun_2/">still active today</a>. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/96242/original/image-20150925-17729-40b5lb.gif?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/96242/original/image-20150925-17729-40b5lb.gif?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=308&fit=crop&dpr=1 600w, https://images.theconversation.com/files/96242/original/image-20150925-17729-40b5lb.gif?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=308&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/96242/original/image-20150925-17729-40b5lb.gif?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=308&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/96242/original/image-20150925-17729-40b5lb.gif?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=387&fit=crop&dpr=1 754w, https://images.theconversation.com/files/96242/original/image-20150925-17729-40b5lb.gif?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=387&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/96242/original/image-20150925-17729-40b5lb.gif?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=387&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Gullies inside a crater in Noachis Terra, 47 degrees south.</span>
<span class="attribution"><a class="source" href="http://photojournal.jpl.nasa.gov/catalog/PIA03205">NASA/JPL/Malin Space Science Systems</a></span>
</figcaption>
</figure>
<p>Are gullies really evidence of flowing water? Some probably are, but there are <a href="http://www.jpl.nasa.gov/news/news.php?release=2014-226">other explanations</a> such as dry rock avalanches or slabs of frozen carbon dioxide scooting downhill. Some gullies start near the tops of sand dunes where an underground reservoir of water is very improbable.</p>
<p>In 2008 the <a href="https://www.nasa.gov/mission_pages/phoenix/main/index.html">lander Phoenix</a> actually saw water on Mars. When it scraped away at the dirt, it found water-ice a few centimetres down, <a href="http://www.space.com/6394-phoenix-mars-lander-liquid-water-scientists.html">but more excitingly droplets</a> that could hardly be anything other than water were seen to form on the lander’s legs. It was suggested that the water had condensed around wind-blown grains of <a href="http://pubchem.ncbi.nlm.nih.gov/compound/61629">calcium perchlorate</a>, a salt mineral whose properties enable it to scavenge water from the air and then dissolve it. Moreover, whereas pure water would freeze at the local temperature at the time (between -10°C and -80°C), water containing enough dissolved salts could stay liquid. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/96231/original/image-20150925-17725-r1tx90.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/96231/original/image-20150925-17725-r1tx90.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=300&fit=crop&dpr=1 600w, https://images.theconversation.com/files/96231/original/image-20150925-17725-r1tx90.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=300&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/96231/original/image-20150925-17725-r1tx90.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=300&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/96231/original/image-20150925-17725-r1tx90.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=377&fit=crop&dpr=1 754w, https://images.theconversation.com/files/96231/original/image-20150925-17725-r1tx90.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=377&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/96231/original/image-20150925-17725-r1tx90.jpg?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">Water droplets on the leg of the Phoenix lander in 2008. Arrow points to the relevant leg.</span>
<span class="attribution"><a class="source" href="https://en.wikipedia.org/wiki/Martian_soil#/media/File:PIA10741_Possible_Ice_Below_Phoenix.jpg">NASA/JPL-Caltech/University of Arizona/Max Planck Institute</a></span>
</figcaption>
</figure>
<h2>Water seeps?</h2>
<p>In 2011 <a href="http://space.unibe.ch/pig/science/lapis/recurring-slope-lineae-rsl.html">a new phenomenon was recognised</a> on high resolution images from orbit by the Mars Reconnaissance Orbiter. These are “recurrent slope lineae” or RSLs, dark downhill streaks that come and go with the seasons (which last about twice as long as seasons on Earth). </p>
<p>They are usually between 0.5m to 5m wide, and not much more than 100m long. These could mark avalanches of dry dust, but the favoured explanation has always been – and which the new NASA find also suggests – is that water is seeping from the ground and wetting the surface enough to darken it, though without flowing in sufficient volume to erode a gully.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/96243/original/image-20150925-17725-1j0ge10.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/96243/original/image-20150925-17725-1j0ge10.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=312&fit=crop&dpr=1 600w, https://images.theconversation.com/files/96243/original/image-20150925-17725-1j0ge10.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=312&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/96243/original/image-20150925-17725-1j0ge10.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=312&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/96243/original/image-20150925-17725-1j0ge10.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=392&fit=crop&dpr=1 754w, https://images.theconversation.com/files/96243/original/image-20150925-17725-1j0ge10.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=392&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/96243/original/image-20150925-17725-1j0ge10.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=392&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Artificial perspective view of the streaks.</span>
<span class="attribution"><span class="source">NASA/JPL/University of Arizona</span></span>
</figcaption>
</figure>
<p>What is most noteworthy about the new research is that it is the first determination of the composition of the streaks. They used an instrument called CRISM (<a href="http://mars.nasa.gov/mro/mission/instruments/crismcompactreconnaissanceimagingspectrometerformars/">Compact Reconnaissance Imaging Spectrometer for Mars</a>) on board the orbiter to analyse the light reflected off the surface of these streaks. In this way, they could show that they contain salts that are most likely to be <a href="http://www.sigmaaldrich.com/catalog/product/sial/222283?lang=en&region=GB">magnesium perchlorate</a>, <a href="http://www.endmemo.com/chem/compound/mgclo3_2.php">magnesium chlorate</a> and <a href="http://www.sigmaaldrich.com/catalog/product/sial/410241?lang=en&region=GB">sodium perchlorate</a>. These kinds of salts have antifreeze properties that would keep water flowing in the cold temperature, and tallies with what Phoenix had suggested in 2008.</p>
<p>There are no signs that liquid water was present when the NASA measurements were made. Scientists will surely keep looking in the same spot in the hope of finding the features that would indicate liquid water instead of those indicative of salts left behind after the water has dried up. However, few can doubt that the salts were put there by flowing water.</p>
<p>Importantly, with liquid water comes the prospect of life on Mars. The researchers cannily conclude by pointing out that in the most arid parts of Earth’s Atacama desert the only source of water for microbes is what they can get from salts dissolved in water. If it can happen on Earth, maybe it can happen on Mars too.</p><img src="https://counter.theconversation.com/content/48182/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>David Rothery is author of Planets: A Very Short Introduction (Oxford University Press, 2010) and Moons: A Very Short Introduction (Oxford University Press, 2015). He receives funding from the UK Space Agency and the Science & Technology Facilities Council for work related to Mercury and the European Space Agency's Mercury orbiter BepiColombo.</span></em></p>New research suggests that salty water exists on Mars in the summer months. But that wouldn’t be the first time we hear of water on the red planet. So what’s new and what isn’t?David Rothery, Professor of Planetary Geosciences, The Open UniversityLicensed as Creative Commons – attribution, no derivatives.