tag:theconversation.com,2011:/uk/topics/space-mission-13320/articlesSpace mission – The Conversation2022-02-21T05:00:45Ztag:theconversation.com,2011:article/1759182022-02-21T05:00:45Z2022-02-21T05:00:45ZJupiter, Saturn, Uranus, Neptune: why our next visit to the giant planets will be so important (and just as difficult)<figure><img src="https://images.theconversation.com/files/446075/original/file-20220213-17-1s3hlo0.jpg?ixlib=rb-1.1.0&rect=15%2C3%2C2580%2C1191&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="https://www.youtube.com/watch?v=sOpMrVnjYeY&t=2225s&ab_channel=SpaceX">SpaceX</a></span></figcaption></figure><p>The giant planets – Jupiter, Saturn, Uranus and Neptune - are some of the most awe-inspiring in our Solar System, and have great importance for space research and our comprehension of the greater universe.</p>
<p>Yet they remain the least explored – especially the “ice giants” Uranus and Neptune – due to their distance from Earth, and the extreme conditions spacecraft must survive to enter their atmospheres. As such, they’re also the least understood planets in the Solar System.</p>
<p>Our <a href="https://arc.aiaa.org/doi/10.2514/1.A34282">ongoing</a> <a href="https://doi.org/10.2514/1.J060560">research</a> looks at how to overcome the harsh entry conditions experienced during giant planet missions. As we look forward to potential future missions, here’s what we might expect.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/446070/original/file-20220213-13-wp9do.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/446070/original/file-20220213-13-wp9do.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/446070/original/file-20220213-13-wp9do.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=227&fit=crop&dpr=1 600w, https://images.theconversation.com/files/446070/original/file-20220213-13-wp9do.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=227&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/446070/original/file-20220213-13-wp9do.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=227&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/446070/original/file-20220213-13-wp9do.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=286&fit=crop&dpr=1 754w, https://images.theconversation.com/files/446070/original/file-20220213-13-wp9do.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=286&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/446070/original/file-20220213-13-wp9do.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=286&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Jupiter is about ten times as large as Earth – with a 69,911km radius (compared to Earth’s 6,371km radius).</span>
<span class="attribution"><span class="source">Beinahegut</span></span>
</figcaption>
</figure>
<h2>But first, what are giant planets?</h2>
<p>Unlike rocky planets, giant planets don’t have a surface to land on. Even in their lower atmospheres they remain gaseous, reaching extremely high pressures that would crush any spacecraft well before it could land on anything solid.</p>
<p>There are two types of giant planets: gas giants and ice giants. </p>
<p>The larger Jupiter and Saturn are gas giants. These are mainly made of hydrogen and helium, with an outer gaseous layer and a partially liquid “metallic” layer below that. They’re also believed to have a small rocky core. </p>
<p>Uranus and Neptune have similar outer atmospheres and rocky cores, but their inner layer is made up of about 65% water and other so-called “ices” (although these technically remain liquid) such as <a href="https://www.lpi.usra.edu/icegiants/mission_study/Exec-Summary.pdf">methane and ammonia</a>.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/446068/original/file-20220213-17-gke7kv.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/446068/original/file-20220213-17-gke7kv.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/446068/original/file-20220213-17-gke7kv.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=338&fit=crop&dpr=1 600w, https://images.theconversation.com/files/446068/original/file-20220213-17-gke7kv.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=338&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/446068/original/file-20220213-17-gke7kv.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=338&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/446068/original/file-20220213-17-gke7kv.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=424&fit=crop&dpr=1 754w, https://images.theconversation.com/files/446068/original/file-20220213-17-gke7kv.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=424&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/446068/original/file-20220213-17-gke7kv.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=424&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Relative size and composition of the giant planets in our solar system (with Earth also shown for comparison).</span>
<span class="attribution"><span class="source">JPL/Caltech (based on material from the Lunar and Planetary Institute)</span></span>
</figcaption>
</figure>
<h2>Slingshots to the edge of the Solar System</h2>
<p>Any giant planet mission is extremely difficult. Still, there have been some past missions sent to the gas giants.</p>
<p>NASA’s 1989 Galileo mission had to slingshot around Venus and Earth to give it enough momentum to <a href="https://www.nasa.gov/feature/30-years-ago-galileo-off-to-orbit-jupiter">get to Jupiter</a>, which it orbited for eight years. The 2011 <a href="https://spaceflight101.com/juno/juno-mission-trajectory-design/">Juno mission</a> spent five years in transit, using a flyby around Earth to reach Jupiter (which it still orbits).</p>
<p>Similarly, the Cassini-Huygens mission run by NASA and the European Space Agency (ESA) <a href="https://sci.esa.int/web/cassini-huygens/-/31240-getting-to-saturn">took seven years</a> to reach Saturn. The spacecraft spent 13 years exploring the planet and its surrounds, and launched a probe to explore Saturn’s moon, <a href="https://solarsystem.nasa.gov/missions/cassini/science/titan/">Titan</a>.</p>
<p>Flight times get even longer for the two ice giants, which are much further from the Sun. Neither has had a dedicated mission so far. </p>
<h2>A complex journey</h2>
<p>The last and only spacecraft to visit the ice giants was <a href="https://solarsystem.nasa.gov/missions/voyager-2/in-depth/">Voyager 2</a>, which flew by Uranus in 1986 and Neptune in 1989. </p>
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<img alt="" src="https://images.theconversation.com/files/446498/original/file-20220215-17-rqmzoy.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/446498/original/file-20220215-17-rqmzoy.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/446498/original/file-20220215-17-rqmzoy.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/446498/original/file-20220215-17-rqmzoy.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/446498/original/file-20220215-17-rqmzoy.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/446498/original/file-20220215-17-rqmzoy.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/446498/original/file-20220215-17-rqmzoy.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">Voyager 2, the only spacecraft ever to have visited Neptune, took a photo of the planet in 1989.</span>
<span class="attribution"><span class="source">NASA/JPL</span></span>
</figcaption>
</figure>
<p>While momentum is building for a return, it won’t be simple. If we launch during the next convenient <a href="https://www.lpi.usra.edu/icegiants/mission_study/Exec-Summary.pdf">launch windows</a> of 2030–34 for Uranus and 2029–30 for Neptune, flight times would vary from 11 to 15 years.</p>
<p>A major issue is power. The Juno spacecraft is the most distant object from the Sun to have <a href="https://www.jpl.nasa.gov/news/nasas-juno-spacecraft-breaks-solar-power-distance-record">used solar panels</a>. It orbits Jupiter, which is <a href="https://solarsystem.nasa.gov/planets/jupiter/in-depth/">five times further away</a> from the Sun than Earth is. Yet, where Juno’s solar cells would generate 14 kilowatts of continuous power on Earth, they only <a href="https://www.jpl.nasa.gov/news/nasas-juno-spacecraft-breaks-solar-power-distance-record">generate 0.5kW at Jupiter</a>. </p>
<p>Meanwhile, Uranus and Neptune are <a href="https://solarsystem.nasa.gov/planets/uranus/in-depth/">20</a> and <a href="https://solarsystem.nasa.gov/planets/neptune/in-depth/">30</a> times further away, respectively, from the Sun than Earth is. Power for these missions would have to be generated from the radioactive <a href="https://solarsystem.nasa.gov/missions/galileo/in-depth/#otp_spacecraft_and_instruments">decay of plutonium</a> (the power source for both the Galileo and Cassini missions). </p>
<p>This radioactive decay can damage and interfere with instruments. It is therefore reserved for spacecraft which really need it, such as missions operating far away from the Sun. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/so-a-helicopter-flew-on-mars-for-the-first-time-a-space-physicist-explains-why-thats-such-a-big-deal-159334">So a helicopter flew on Mars for the first time. A space physicist explains why that's such a big deal</a>
</strong>
</em>
</p>
<hr>
<h2>Fighting the heat</h2>
<p>The massive scale of giant planets means orbit speeds for incoming spacecraft are incredibly fast. And these speeds greatly heat up the spacecraft. </p>
<p>The Galileo probe entered Jupiter’s atmosphere at <a href="https://solarsystem.nasa.gov/missions/galileo-probe/in-depth/">47.5 kilometres per second</a>, surviving the harshest entry conditions ever experienced by an entry probe. The shock layer which formed at the front of the spacecraft during entry reached a temperature of 16,000°C – around three times the temperature of the Sun’s surface.</p>
<p>Even so, the distribution of the <a href="https://arc.aiaa.org/doi/10.2514/2.3293">heat shield’s</a> mass was found to be inefficient – showing we still have a lot to learn about entering giant planets.</p>
<p>Proposed future probe missions to Uranus and Neptune would occur at slower entry speeds of <a href="https://link.springer.com/article/10.1007/s11214-020-0638-2">22km/s and 26km/s</a>, respectively. </p>
<p>For this, NASA have developed a tough but relatively lightweight material woven from carbon fibre, called <a href="https://www.nasa.gov/ames/heeet">HEEET</a> (Heatshield for Extreme Entry Environment Technology), designed specifically for surviving giant planet and Venusian entry. </p>
<p>While the material has been tested with a <a href="https://www.nasa.gov/centers/ames/entry-systems-vehicle-development/tps-materials.html">full-scale prototype</a>, it has yet to fly on a mission.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/446526/original/file-20220215-8037-1brq7ct.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/446526/original/file-20220215-8037-1brq7ct.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/446526/original/file-20220215-8037-1brq7ct.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/446526/original/file-20220215-8037-1brq7ct.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/446526/original/file-20220215-8037-1brq7ct.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/446526/original/file-20220215-8037-1brq7ct.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/446526/original/file-20220215-8037-1brq7ct.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">It’s planned NASA’s HEEET material will be used for future ice giant entry missions.</span>
<span class="attribution"><span class="source">NASA</span></span>
</figcaption>
</figure>
<h2>The next steps</h2>
<p>In 2024, NASA’s Europa Clipper mission <a href="https://europa.nasa.gov/">will launch</a> to investigate Jupiter’s moon Europa, which is believed to house an <a href="https://europa.nasa.gov/why-europa/overview/">ocean of liquid water</a> below its icy surface, where signs of life may be found. The <a href="https://www.nasa.gov/press-release/nasas-dragonfly-will-fly-around-titan-looking-for-origins-signs-of-life/">Dragonfly</a> mission, planned to launch in 2026, will similarly aim to search for signs of life on Saturn’s moon Titan.</p>
<p>There are plans for a joint <a href="https://www.sciencedirect.com/science/article/pii/S0032063318303507">NASA-ESA mission</a> to visit one of the ice giants within the upcoming launch window. But while there has been <a href="https://www.lpi.usra.edu/icegiants/documents_presentations/">extensive</a> <a href="https://sci.esa.int/web/future-missions-department/-/61307-cdf-study-report-ice-giants">preparation</a>, it’s undecided which ice giant will be visited. </p>
<p>A single mission to both planets is being considered. An entry probe is planned, too. But if the mission visits both planets, it’s undecided which planet’s <a href="https://www.sciencedirect.com/science/article/pii/S003206331830350">atmosphere the probe would explore</a>.</p>
<p>If we want to meet the upcoming launch window, it’s expected mission concepts will need to be finalised <a href="https://www.sciencedirect.com/science/article/pii/S0032063320300040">by 2025</a>, at the latest. In other words, crunch time is coming. </p>
<p>Should a mission go forward, the two most important <a href="https://www.lpi.usra.edu/icegiants/mission_study/Full-Report.pdf">goals</a> for NASA’s scientists will be to determine the interior makeup of ice giants (exactly what they are made of) and their composition (how they are formed).</p>
<p>Other objectives will include studying their magnetic fields, which are <a href="https://www.lpi.usra.edu/icegiants/mission_study/Full-Report.pdf">very different</a> to gas giants and all other types of planets. </p>
<p>They’ll also want to study the heat released by both Uranus and Neptune, which both have average temperatures of around -200°C. All giant planets are meant to be very slowly cooling down, as they release energy gained during their formation. </p>
<p>This heat release can be detected for Jupiter, Saturn and Neptune. Uranus, however, doesn’t seem to release heat – and scientists don’t know why.</p><img src="https://counter.theconversation.com/content/175918/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Chris James receives funding from the University of Queensland, the Australian Research Council, and the U.S. Office of Naval Research. </span></em></p><p class="fine-print"><em><span>Yu Liu does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>There has never been a dedicated mission sent to the “ice giants”, Uranus and Neptune. But there may be one on the horizon.Chris James, ARC DECRA Fellow, Centre for Hypersonics, School of Mechanical and Mining Engineering, The University of QueenslandYu Liu, Honorary Fellow, The University of QueenslandLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1726032021-11-26T05:23:39Z2021-11-26T05:23:39ZCould we really deflect an asteroid heading for Earth? An expert explains NASA’s latest DART mission<figure><img src="https://images.theconversation.com/files/434110/original/file-20211126-19-h79etv.jpeg?ixlib=rb-1.1.0&rect=0%2C72%2C5376%2C2945&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><span class="source">Shutterstock</span></span></figcaption></figure><p>A NASA spacecraft the size of a golf cart has been directed to smash into an asteroid, with the intention of knocking it slightly off course. The test aims to demonstrate our technological readiness in case an actual asteroid threat is detected in the future.</p>
<p>The Double Asteroid Redirection Test (DART) lifted off aboard a SpaceX rocket from California on November 23, and will arrive at the target asteroid system in September, next year. </p>
<p>The mission will travel to the asteroid Didymos, a member of the <a href="https://cneos.jpl.nasa.gov/about/neo_groups.html">Amor group of asteroids</a>. Every 12 hours Didymos is orbited by a mini-moon, or “moonlet”, Dimorphos. This smaller half of the pair will be DART’s target.</p>
<h2>Are we facing an extinction threat from asteroids?</h2>
<p>We’ve all seen disaster movies in which an asteroid hits Earth, creating an extinction event similar to the one that killed off the dinosaurs millions of years ago. Could that happen now? </p>
<p>Well, Earth is actually bombarded frequently by small asteroids, ranging from 1-20 metres in diameter. Almost all asteroids of this size disintegrate in the atmosphere and are usually harmless. </p>
<p>There is an <a href="https://en.wikipedia.org/wiki/Impact_event">inverse relationship</a> between the size of these objects and the frequency of impact events. This means we get hit much more frequently by small objects than larger ones – simply because there are many more smaller objects in space.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/434047/original/file-20211125-21-1lg3gh9.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/434047/original/file-20211125-21-1lg3gh9.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/434047/original/file-20211125-21-1lg3gh9.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=420&fit=crop&dpr=1 600w, https://images.theconversation.com/files/434047/original/file-20211125-21-1lg3gh9.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=420&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/434047/original/file-20211125-21-1lg3gh9.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=420&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/434047/original/file-20211125-21-1lg3gh9.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=528&fit=crop&dpr=1 754w, https://images.theconversation.com/files/434047/original/file-20211125-21-1lg3gh9.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=528&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/434047/original/file-20211125-21-1lg3gh9.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=528&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Small asteroid impacts showing day-time impacts (in yellow) and night-time impacts (in blue). The size of each dot is proportional to the optical radiated energy of the impact.</span>
<span class="attribution"><span class="source">NASA JPL</span></span>
</figcaption>
</figure>
<p>Asteroids with a 1km diameter strike Earth every 500,000 years, on average. The most “recent” impact of this size is thought to have formed the <a href="https://en.wikipedia.org/wiki/Tenoumer_crater">Tenoumer impact crater in Mauritania</a>, 20,000 years ago. Asteroids with an approximate 5km diameter impact Earth about once every 20 million years. </p>
<p>The <a href="https://earthsky.org/space/meteor-asteroid-chelyabinsk-russia-feb-15-2013/">2013 Chelyabinsk meteoroid</a>, which damaged buildings in six Russian cities and injured around 1,500 people, was estimated to be about 20m in diameter.</p>
<h2>Assessing the risk</h2>
<p>NASA’s DART mission has been sparked by the threat and fear of a major asteroid hitting Earth in the future. </p>
<p>The <a href="https://en.wikipedia.org/wiki/Torino_scale">Torino scale</a> is a method for categorising the impact hazard associated with a near-Earth object (NEO). It uses a scale from 0 to 10, wherein 0 means there is negligibly small chance of collision, and 10 means imminent collision, with the impacting object being large enough to precipitate a global disaster.</p>
<p>The <a href="https://www.planetary.org/notable-asteroid-impacts-in-earths-history">Chicxulub impact</a> (which is attributed to the extinction of non-avian dinosaurs) was a Torino scale 10. The impacts that created the Barringer Crater, and the 1908 Tunguska event, both correspond to Torino Scale 8. </p>
<p>With the increase of online news and individuals’ ability to film events, asteroid “near-misses” tend to generate fear in the public. Currently, NASA is keeping a close eye on asteroid Bennu, which is the object with the largest “cumulative hazard rating” right now. (You can keep <a href="https://cneos.jpl.nasa.gov/sentry/">up to date too</a>).</p>
<p>With a 500m diameter, Bennu is capable of creating a 5km crater on Earth. However, NASA has also said there is a 99.943% chance the asteroid will miss us.</p>
<h2>Brace for impact</h2>
<p>At one point in their orbit around the Sun, Didymos and Dimorphos come within about 5.9 million km of Earth. This is still further away than our Moon, but it’s very close in astronomical terms, so this is when DART will hit Dimorphos.</p>
<p><a href="https://dart.jhuapl.edu/Mission/Impactor-Spacecraft.php">DART</a> will spend about ten months travelling towards Didymos and, when it’s close by, will change direction slightly to crash into Dimorphos at a speed of about 6.6km per second.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/434097/original/file-20211126-15-1ve7m9j.gif?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/434097/original/file-20211126-15-1ve7m9j.gif?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/434097/original/file-20211126-15-1ve7m9j.gif?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/434097/original/file-20211126-15-1ve7m9j.gif?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/434097/original/file-20211126-15-1ve7m9j.gif?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/434097/original/file-20211126-15-1ve7m9j.gif?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/434097/original/file-20211126-15-1ve7m9j.gif?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">This animation shows DART’s trajectory around the Sun. Pink = DART | Green = Didymos | Blue = Earth | Turquoise = 2001 CB21 | Gold = 3361 Orpheus.</span>
</figcaption>
</figure>
<p>The larger Didymos is 780m in diameter and thus makes a better target for DART to aim for. Once DART has detected the much smaller Dimorphos, just 160m in diameter, it can make a last-minute course correction to collide with the moonlet. </p>
<p>The mass of Dimorphos is 4.8 million tonnes and the mass of DART at impact will be about 550kg. Travelling at 6.6km/s, DART will be able to transfer a huge amount of momentum to Dimorphos, to the point where it’s expected to actually change the moonlet’s orbit around Didymos.</p>
<p>This change, to the tune of about 1%, will be detected by ground telescopes within weeks or months. While this may not seem like a lot, 1% is actually a promising shift. If DART were to slam into a lone asteroid, its orbital period around the Sun would change by only about 0.000006%, which would take many years to measure. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/433919/original/file-20211125-1794-vtv1ni.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/433919/original/file-20211125-1794-vtv1ni.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/433919/original/file-20211125-1794-vtv1ni.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=340&fit=crop&dpr=1 600w, https://images.theconversation.com/files/433919/original/file-20211125-1794-vtv1ni.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=340&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/433919/original/file-20211125-1794-vtv1ni.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=340&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/433919/original/file-20211125-1794-vtv1ni.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=427&fit=crop&dpr=1 754w, https://images.theconversation.com/files/433919/original/file-20211125-1794-vtv1ni.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=427&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/433919/original/file-20211125-1794-vtv1ni.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=427&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 DART mission dates and timeline events.</span>
<span class="attribution"><span class="source">Johns Hopkins University</span></span>
</figcaption>
</figure>
<p>So we’ll be able to detect the 1% change from Earth, and meanwhile the pair will continue along its orbit around the Sun. DART will also deploy a small satellite ten days before impact to capture everything.</p>
<p>This is NASA’s first mission dedicated to demonstrating a <a href="https://www.nasa.gov/feature/nasa-s-first-planetary-defense-technology-demonstration-to-collide-with-asteroid-in-2022">planetary defence technique</a>. At a cost of US$330 million, it’s relatively cheap in space mission terms. The <a href="https://www.nasa.gov/mission_pages/webb/about/index.html">James Webb Telescope</a> set to launch next month, costs close to <a href="https://www.planetary.org/articles/cost-of-the-jwst">US$10 billion</a>.</p>
<p>There will be little to no debris from DART’s impact. We can think of it in terms of a comparable event on Earth; imagine a train parked on the tracks but with no brakes on. Another train comes along and collides with it. </p>
<p>The trains won’t break apart, or destroy one another, but will move off together. The stationary one will gain some speed, and the one impacting it will lose some speed. The trains combine to become a new system with different speeds than before. </p>
<p>So we won’t experience any impact, ripples or debris from the DART mission.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/434099/original/file-20211126-21-1jrvgbd.PNG?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/434099/original/file-20211126-21-1jrvgbd.PNG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=426&fit=crop&dpr=1 600w, https://images.theconversation.com/files/434099/original/file-20211126-21-1jrvgbd.PNG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=426&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/434099/original/file-20211126-21-1jrvgbd.PNG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=426&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/434099/original/file-20211126-21-1jrvgbd.PNG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=535&fit=crop&dpr=1 754w, https://images.theconversation.com/files/434099/original/file-20211126-21-1jrvgbd.PNG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=535&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/434099/original/file-20211126-21-1jrvgbd.PNG?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=535&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Typical asteroid orbits remain between Mars and Jupiter, but some with elliptical orbits can pass close to Earth.</span>
<span class="attribution"><span class="source">Pearson</span></span>
</figcaption>
</figure>
<h2>Is the effort really worth it?</h2>
<p>Results from the mission will tell us just how much mass and speed is needed to hit an asteroid that may pose a threat in the future. We already track the vast majority of asteroids that come close to Earth, so we would have early warning of any such object.</p>
<p>That said, we have <a href="https://www.livescience.com/surprise-asteroid-flyby">missed objects in the past</a>. In October 2021, <a href="https://en.wikipedia.org/wiki/2021_UA1">Asteroid UA_1</a> passed about 3,047km from Earth’s surface, over Antarctica. We missed it because it approached from the direction of the Sun. At just 1m in size it wouldn’t have caused much damage, but we should have seen it coming. </p>
<p>Building a deflection system for a potential major asteroid threat would be difficult. We would have to act quickly and hit the target with very good aim. </p>
<p>One candidate for such a system could be the new technology developed by the US spaceflight company <a href="https://www.spinlaunch.com/">SpinLaunch</a>, which has designed technology to launch satellites into orbit at rapid speeds. This device could also be used to fire masses at close-passing asteroids. </p>
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Read more:
<a href="https://theconversation.com/where-do-meteorites-come-from-we-tracked-hundreds-of-fireballs-streaking-through-the-sky-to-find-out-160096">Where do meteorites come from? We tracked hundreds of fireballs streaking through the sky to find out</a>
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<img src="https://counter.theconversation.com/content/172603/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Gail Iles does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>An asteroid that landed in Russia in 2013 injured 1,500 people – and was just 20 metres in diameter. What could we do if a major threat was detected?Gail Iles, Senior Lecturer in Physics, RMIT UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1700972021-11-03T19:07:36Z2021-11-03T19:07:36ZAustralia is putting a rover on the Moon in 2024 to search for water<figure><img src="https://images.theconversation.com/files/429881/original/file-20211103-13-g3sduq.png?ixlib=rb-1.1.0&rect=2%2C15%2C1495%2C613&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><span class="source">ispace</span></span></figcaption></figure><p>Last month the Australian Space Agency <a href="https://www.theguardian.com/science/2021/oct/13/australia-to-build-20kg-rover-to-head-to-moon-in-joint-mission-with-nasa">announced</a> plans to send an Australian-made rover to the Moon by as early as 2026, under a deal with NASA. The rover will collect lunar soil containing oxygen, which could eventually be used to support human life in space. </p>
<p>Although the <a href="https://www.pm.gov.au/media/australias-first-mission-moon">deal with NASA</a> made headlines, a separate mission conducted by private companies in Australia and Canada, in conjunction with the University of Technology Sydney, may see Australian technology hunting water on the Moon as soon as mid-2024.</p>
<p>If all goes according to plan, it will be the first rover with Australian-made components to make it to the Moon. </p>
<h2>Roving in search of water</h2>
<p>The ten-kilogram rover, measuring 60x60x50cm, will be launched on board the Hakuto lander made by <a href="https://ispace-inc.com/">ispace</a>, a lunar robotic exploration company based in Japan. </p>
<p>The rover itself, also built by ispace, will have an integrated robotic arm created by the private companies <a href="https://stardust-technologies.com/">Stardust Technologies</a> (based in Canada) and Australia’s <a href="https://www.explorespace.com.au/">EXPLOR Space Technology</a> (of which I am one of the founders).</p>
<p>Using cameras and sensors, the arm will collect high-resolution visual and haptic data to be sent back to the mission control centre at the University of Technology Sydney.</p>
<p>It will also collect information on the physical and chemical composition of lunar dust, soil and rocks — specifically with a goal of finding water. We know water is present within the Moon’s soil, but we have yet to find a way to extract it for practical use. </p>
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<strong>
Read more:
<a href="https://theconversation.com/water-on-the-moon-research-unveils-its-type-and-abundance-boosting-exploration-plans-148669">Water on the Moon: research unveils its type and abundance – boosting exploration plans</a>
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<p>The big push now is to identify regions on the Moon where water sources are more abundant, and which can deliver more usable water for human consumption, sample processing, mining operations and food growth.</p>
<p>This would also set the foundation for the establishment of a manned Moon base, which could serve as a transit station for further space exploration (including on Mars). </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/429440/original/file-20211031-15910-fccea3.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/429440/original/file-20211031-15910-fccea3.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=800&fit=crop&dpr=1 600w, https://images.theconversation.com/files/429440/original/file-20211031-15910-fccea3.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=800&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/429440/original/file-20211031-15910-fccea3.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=800&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/429440/original/file-20211031-15910-fccea3.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1005&fit=crop&dpr=1 754w, https://images.theconversation.com/files/429440/original/file-20211031-15910-fccea3.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1005&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/429440/original/file-20211031-15910-fccea3.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1005&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
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<span class="caption">The ispace moon lander was displayed in Washington DC.</span>
<span class="attribution"><span class="source">Courtesy of Australian Embassy staff</span></span>
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</figure>
<h2>Moon-grade materials</h2>
<p>Once the Hakuto lander takes off, the first challenge will be to ensure it lands successfully with the rover intact. The rover will have to survive an extreme environment on the lunar surface.</p>
<p>As the moon rotates relative to the Sun, it experiences day and night cycles, just like Earth. But one day on the Moon lasts 29.5 Earth days. And surface temperatures shift dramatically during this time, reaching up to 127°C during the day and falling as low as -173°C at night.</p>
<p>The rover and robotic arm will also need to withstand the effects of space radiation, vibrations during launch, shock from the launch and landing, and exposure to dust and water. </p>
<p>At the same time, the arm must be light enough to conduct advanced manoeuvres, such as grabbing and collecting moon rocks. Advanced space-grade aluminium developed in Australia will help protect it from damage. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/429443/original/file-20211031-15-1csuz38.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/429443/original/file-20211031-15-1csuz38.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/429443/original/file-20211031-15-1csuz38.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/429443/original/file-20211031-15-1csuz38.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/429443/original/file-20211031-15-1csuz38.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/429443/original/file-20211031-15-1csuz38.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/429443/original/file-20211031-15-1csuz38.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">The TechLab antenna chamber at the The University of Technology Sydney is being used to test communication signals which will be critical to this mission.</span>
</figcaption>
</figure>
<p>The team behind the mission is currently in the process of testing different designs of the robotic arm, and figuring out the best way to integrate it with the rover. It will be tested together with the rover at a new lunar test bed, at the EXPLOR Space Technologies facility in New South Wales. </p>
<p>Like the one used by NASA, this test bed can mimic the physical and chemical conditions on the Moon. It will be critical to determining whether the rover can stay mobile and continue to function under different environmental stressors.</p>
<h2>Step into your astronaut boots</h2>
<p>The rover will also send back data that allows people on Earth to experience the Moon with virtual reality (VR) goggles and a sensor glove. Haptic data collected back by the robotic arm will essentially let us “feel” anything the arm touches on the lunar surface.</p>
<p>We plan to make the experience available as a free app — and hope it inspires future generations of space explorers.</p>
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Read more:
<a href="https://theconversation.com/so-a-helicopter-flew-on-mars-for-the-first-time-a-space-physicist-explains-why-thats-such-a-big-deal-159334">So a helicopter flew on Mars for the first time. A space physicist explains why that's such a big deal</a>
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<img src="https://counter.theconversation.com/content/170097/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Joshua Chou is the co-founder of EXPLOR Space Technologies. </span></em></p>A 10kg rover, due to land on the Moon by 2024, will be fitted with an advanced robotic arm design and manufactured in Australia.Joshua Chou, Senior lecturer, University of Technology SydneyLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1593342021-04-20T05:00:32Z2021-04-20T05:00:32ZSo a helicopter flew on Mars for the first time. A space physicist explains why that’s such a big deal<p>Yesterday at 9pm Australian Eastern standard time, the Ingenuity helicopter — which landed on Mars with <a href="https://mars.nasa.gov/mars2020/mission/overview/">the Perseverance rover</a> in February — <a href="https://www.abc.net.au/news/science/2021-04-19/nasa-ingenuity-helicopter-makes-historic-first-flight-on-mars/100056708">took off</a> from the Martian surface. More importantly, it hovered for about 30 seconds, three metres above the surface and came right back down again.</p>
<p>It may not sound like a huge feat, but it is. Ingenuity’s flight is the first powered flight of an aircraft on another planet. It marks a milestone in the story of human space exploration. </p>
<p>While the Apollo 11 spacecraft famously touched down on the Moon, upon re-launch it simply had to exit the Moon’s gravity and return to Earth. To sustain flight within the environment of a world with no atmosphere, however, is a different story.</p>
<p>The now historic Ingenuity helicopter took <a href="https://www.nasa.gov/press-release/nasa-ingenuity-mars-helicopter-prepares-for-first-flight">six years</a> to make. We can understand why, once we understand the complexities of what was required.</p>
<p><div data-react-class="Tweet" data-react-props="{"tweetId":"1384209173924089863"}"></div></p>
<h2>Why local flight on Mars is a big deal</h2>
<p>There are several technological challenges to conducting a helicopter flight on another world. First, and most significantly, helicopters need an atmosphere to fly.</p>
<p>The blades, or “rotors” of a helicopter must spin fast enough to generate a force called “lift”. But lift can only be generated in the presence of some kind of atmosphere. While Mars does have an atmosphere, it’s much, much thinner than Earth’s — <a href="https://www.space.com/16903-mars-atmosphere-climate-weather.html">about 100 times thinner, in fact</a>.</p>
<p>Flying Ingenuity in Mars’s atmosphere is therefore the equivalent of flying a helicopter on Earth at a height of 100,000 feet. For reference, commercial aircraft fly between 30,000-40,000 feet above the Earth’s surface and the highest we’ve ever been in a <a href="https://en.wikipedia.org/wiki/Flight_altitude_record">helicopter on Earth is 42,000 feet</a>.</p>
<p>Testing the craft on Earth required a pressurised room, from which a lot of air would have been extracted to emulate Mars’s atmosphere. </p>
<p>Then there’s the Martian gravity to consider, which is about one-third the strength of gravity on Earth. This actually gives us a slight advantage. If Mars had the same atmosphere as Earth, it’s lesser gravity means we’d be able to lift Ingenuity with less power than would be required here.</p>
<p>But while Mars’s gravity works to our advantage, this is offset by the lack of atmosphere. </p>
<p>Ingenuity’s success marks the first time such a flight has even been attempted outside of Earth. And the reason for this may simply be that, as laid out above, this task is very, very difficult. </p>
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Read more:
<a href="https://theconversation.com/7-minutes-of-terror-a-look-at-the-technology-perseverance-will-need-to-survive-landing-on-mars-155046">'7 minutes of terror': a look at the technology Perseverance will need to survive landing on Mars</a>
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<h2>Advanced manufacturing</h2>
<p>There are two main ways Ingenuity was able to overcome the hurdles presented in Mars’s atmosphere. Firstly, to generate lift, the two rotors (<a href="https://www.nasa.gov/feature/jpl/6-things-to-know-about-nasas-ingenuity-mars-helicopter">made from carbon fibre</a>) had to spin much faster than any helicopter’s on Earth.</p>
<p>On Earth, most helicopters and drones have rotors that spin at about 400-500 revolutions per minute. The Ingenuity’s rotor spun at about 2,400 revolutions per minute.</p>
<p>It also has a distinct aircraft-to-wingspan ratio. While Ingenuity’s body is about the size of a tissue box, its blades are 1.2m from tip to tip. </p>
<p>Even transmitting the signal for the flight to begin required an array of advanced technology. Whilst it only requires minutes for radio signals to travel between Earth and Mars, there was still a <a href="https://www.jpl.nasa.gov/news/nasas-ingenuity-mars-helicopter-succeeds-in-historic-first-flight">delay of hours</a> for those signals to reach the helicopter. </p>
<p>This makes sense when you consider the journey those signals have to take – from a computer on Earth, to a satellite dish, to the Mars Reconnaissance Orbiter, to the Perseverance rover and then, finally, to the helicopter.</p>
<h2>Remote controlled flight on Mars</h2>
<p>Ingenuity is what we call a “technology demonstrator”. Simply, its only purpose is to prove it can complete a series of simple missions. Over the next few weeks, the helicopter will undertake three or four more flights, the most adventurous of which will involve taking off and travelling about 300m away from Perseverance.</p>
<p>Data retrieved from the flights will be analysed and used as crucial input for future designs of more sophisticated aircraft. Once this technology is applied, its potential will be vast. </p>
<p>Drones and helicopters operating on Mars could act as scouts, checking the land ahead of a rover to confirm whether it’s safe to travel there. Such aircraft could even assist in the search for water and life on the Martian surface.</p>
<p>And in 2035, <a href="https://www.space.com/nasa-aims-for-2035-mars-landings-iac.html">it’s expected</a> the first humans will land on Mars. There’s a good chance these crews will be trained in operating aircraft locally and in real-time, surveying the land for obstacles and dangerous terrain that could harm humans, or damage suits, aircraft or rovers.</p>
<h2>Homage to the past, with the future in sight</h2>
<p>As a touching tribute to the first powered flight on Earth, scientists at the NASA Jet Propulsion Laboratory added a historic artefact to the Mars helicopter. Attached to a cable underneath one of its solar panels is a small piece of the wing from the Wright brothers’ 1903 Wright flyer. </p>
<p>This item of flight history is the second piece of an Earth aircraft to go into space; a similar piece of the wing was taken to the Moon during the Apollo missions.</p>
<p>Missions are already in work to push the barriers of powered flight on other worlds. In particular, the <a href="https://www.nasa.gov/press-release/nasas-dragonfly-will-fly-around-titan-looking-for-origins-signs-of-life">Dragonfly helicopter</a> is planned to fly above the surface of Titan, one of Saturn’s moons, with arrival scheduled for 2034. </p>
<p>Maybe it too will take a piece of Earth’s history along for the ride as we continue our exploration of other planetary bodies, one world at a time. </p>
<p><div data-react-class="Tweet" data-react-props="{"tweetId":"1384099929128202240"}"></div></p><img src="https://counter.theconversation.com/content/159334/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Gail Iles does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Flying the Ingenuity helicopter on Mars is the equivalent of flying one at about 100,000 feet on Earth. Tricky, considering the highest helicopter flight ever recorded maxed out at 42,000 feet.Gail Iles, Senior Lecturer in Physics, RMIT UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1347622020-04-20T12:27:09Z2020-04-20T12:27:09ZCoronavirus quarantine could provide lessons for future space travel on how regular people weather isolation<figure><img src="https://images.theconversation.com/files/328945/original/file-20200419-152607-srew47.jpg?ixlib=rb-1.1.0&rect=94%2C176%2C2208%2C1376&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">A researcher in a spacesuit on "Mars" outside the Mars Society Desert Research Station in Utah.</span> <span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/news-photo/researcher-in-a-space-suit-on-mars-at-the-mars-society-news-photo/528988124">David Howells/Corbis Historical via Getty Images</a></span></figcaption></figure><p>I was supposed to travel to “Mars” this month. The plan was to stay two weeks at the <a href="http://mdrs.marssociety.org/">Mars Desert Research Station</a> – actually in the Utah desert – to simulate human operations on the red planet. Eight of us were to live in a two-story cylinder, 24 feet in diameter. We would conserve water and put on mock spacesuits every time we ventured outside.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/328946/original/file-20200419-152602-19ls8ka.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/328946/original/file-20200419-152602-19ls8ka.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/328946/original/file-20200419-152602-19ls8ka.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=389&fit=crop&dpr=1 600w, https://images.theconversation.com/files/328946/original/file-20200419-152602-19ls8ka.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=389&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/328946/original/file-20200419-152602-19ls8ka.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=389&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/328946/original/file-20200419-152602-19ls8ka.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=489&fit=crop&dpr=1 754w, https://images.theconversation.com/files/328946/original/file-20200419-152602-19ls8ka.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=489&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/328946/original/file-20200419-152602-19ls8ka.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=489&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Previous visitors explore the terrain outside the research station.</span>
<span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/news-photo/veronica-ann-zabala-aliberto-from-arizona-state-university-news-photo/53090509">George Frey/Getty Images News via Getty Images</a></span>
</figcaption>
</figure>
<p>But, in an ironic twist, the coronavirus pandemic and the worldwide spread of social distancing put on hold our simulation of isolation on Mars.</p>
<p>My main goal had been to collect data for my dissertation. <a href="https://scholar.google.com/citations?user=IgwvhPwAAAAJ&hl=en&oi=ao">I research groups in space-analog environments</a> – isolated and confined places that share characteristics with human space missions. I’m especially interested in the way gender contributes to individuals’ influence within a group and how men and women manage their emotions in isolation and confinement.</p>
<p>I will not go to “Mars” this spring. As I am self-isolating at home, though, I keep thinking about what lessons for future space travel the current situation can provide. <a href="https://www.nytimes.com/2020/03/21/opinion/scott-kelly-coronavirus-isolation.html">Astronauts have shared tips</a> on how to survive long periods of loneliness and isolation. Maybe in return, the experiences of millions living under lockdown can offer insights into previously understudied social effects of isolation and aid future space travel.</p>
<p>Let me be clear: By no means am I denying the seriousness of the pandemic, and I am not reducing vitally important social distancing measures to a set of convenient social observations.</p>
<p>However, the more researchers understand the social effects of isolation on regular people – as opposed to those certified to have “the right stuff” – the better we will be prepared for the future, whether another wave of pandemic or interplanetary space travel.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/328816/original/file-20200417-152558-2kbd75.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/328816/original/file-20200417-152558-2kbd75.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/328816/original/file-20200417-152558-2kbd75.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=399&fit=crop&dpr=1 600w, https://images.theconversation.com/files/328816/original/file-20200417-152558-2kbd75.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=399&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/328816/original/file-20200417-152558-2kbd75.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=399&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/328816/original/file-20200417-152558-2kbd75.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=501&fit=crop&dpr=1 754w, https://images.theconversation.com/files/328816/original/file-20200417-152558-2kbd75.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=501&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/328816/original/file-20200417-152558-2kbd75.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=501&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Tight quarters, nowhere to go – sound familiar?</span>
<span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/handsome-gay-couple-experiencing-relationship-royalty-free-image/871172826">Fertnig/E+ via Getty Images</a></span>
</figcaption>
</figure>
<h2>Homes as real-world isolation capsules</h2>
<p>Most group behavior research in space and space-analog environments <a href="https://www.ncbi.nlm.nih.gov/pubmed/11865866">focuses on leadership, cohesion and conflict</a> – factors that affect teams’ performance and their ability to complete tasks. It makes sense, as astronauts are first and foremost a team of co-workers on a specific mission.</p>
<p>But, by focusing on the professional level, researchers overlook other potential relationships between crew members – such as family ties or intimacy. It is not a minor detail: <a href="https://doi.org/10.1037/0022-3514.72.4.775">Interpersonal relationships can certainly change</a> dynamics of group behavior. If you’ve ever shared a workplace with a romantic couple, for instance, you probably know there can be some drama.</p>
<p>So far, only <a href="https://www.vice.com/en_us/article/3dky9w/sex-in-space">one married couple</a> has been to space. Researchers suggest that <a href="https://doi.org/10.1016/S0094-5765(03)80003-6">couples are better equipped to handle isolation</a> because of mutual social support. Having couples on board makes the team feel closer as a whole.</p>
<p>However, anecdotal evidence from China suggests that <a href="https://www.bloomberg.com/news/articles/2020-03-31/divorces-spike-in-china-after-coronavirus-quarantines">divorce rates jumped after the quarantine</a>. This factoid suggests that it’s not clear whether average real-world couples are better suited for isolation than single individuals.</p>
<h2>Gender dynamics, at home and in space</h2>
<p>Now, researchers like me have an opportunity to understand how couple dynamics influence life in isolation – including sex and sexuality, questions that NASA is <a href="https://fivethirtyeight.com/features/space-sex-is-serious-business/">not eager to address</a>. While pregnancy can be dangerous, intimacy and sexuality can <a href="https://theconversation.com/sex-in-space-could-technology-meet-astronauts-intimate-needs-131630">improve emotional and mental well-being</a> over long periods of social isolation.</p>
<p>In addition to intimate relationships, current isolation conditions mean researchers could pay more attention to structural gender inequalities accentuated by the pandemic. Women in general do <a href="https://www.penguinrandomhouse.com/books/310593/the-second-shift-by-arlie-hochschild-with-anne-machung/9780143120339">more unpaid domestic and care labor</a>, as well as more <a href="https://doi.org/10.1111/j.0022-2445.2005.00120.x">emotional labor</a> – taking care of others’ feelings and well-being in addition to their own.</p>
<p>Now, their toll is <a href="https://www.theatlantic.com/international/archive/2020/03/feminism-womens-rights-coronavirus-covid19/608302/">increasing</a>. Men and women have the same general goal – to survive the pandemic and its aftermath – but they experience the quarantine differently. In most middle-class families, the traditional work-home divide is now gone, as both partners work from home. But women are still likely to <a href="https://thehill.com/changing-america/respect/equality/488509-the-hidden-burden-of-the-coronavirus-on-women">spend more time</a> running the household, including child and elderly care.</p>
<p>While at this stage there are no screaming toddlers in space, space-analog research shows similar trends of <a href="https://www.ncbi.nlm.nih.gov/pubmed/15943200">women taking care of other crew members</a>. The widespread lockdown could allow researchers to get more data on how social norms and expectations about each gender – for example, who is supposed to offer more emotional support – influence behavior in mixed-gender groups in highly uncertain and stressful situations.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/328817/original/file-20200417-152602-1splj72.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/328817/original/file-20200417-152602-1splj72.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/328817/original/file-20200417-152602-1splj72.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=441&fit=crop&dpr=1 600w, https://images.theconversation.com/files/328817/original/file-20200417-152602-1splj72.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=441&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/328817/original/file-20200417-152602-1splj72.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=441&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/328817/original/file-20200417-152602-1splj72.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=554&fit=crop&dpr=1 754w, https://images.theconversation.com/files/328817/original/file-20200417-152602-1splj72.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=554&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/328817/original/file-20200417-152602-1splj72.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=554&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Will screens prove to be enough?</span>
<span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/chinese-woman-sitting-on-sofa-with-friend-using-royalty-free-image/1006511974">10'000 Hours/DigitalVision via Getty Images</a></span>
</figcaption>
</figure>
<h2>Connecting while physically apart</h2>
<p>Whether you are in deep space or in quarantine, communication with family and friends outside is crucial for your well-being. </p>
<p>In the past weeks, social lives have <a href="https://www.theatlantic.com/family/archive/2020/03/zoom-college-party-memes-page-dating-ok-zoomer/608617/">moved online</a>, from work conference calls to Friday night trivia. The current situation can help to settle the debate <a href="https://doi.org/10.1016/j.jagp.2018.10.014">whether online communication can</a> or <a href="https://doi.org/10.1037/0033-3204.40.1-2.155">cannot replace</a> real-life conversations. What forms of digital communications are closest to meeting a friend for a real cup of coffee? How often should astronauts host a digital happy hour en route to Mars?</p>
<p>There is no doubt that coronavirus-caused social isolation will take a toll on individual and collective mental health. But staying home saves lives. Maybe this experience will also provide lessons on how to plan for <a href="https://techcrunch.com/2019/11/07/elon-musk-says-building-the-first-sustainable-city-on-mars-will-take-1000-starships-and-20-years/">future cities and social life</a> on another planet.</p>
<p>[<em>You need to understand the coronavirus pandemic, and we can help.</em> <a href="https://theconversation.com/us/newsletters?utm_source=TCUS&utm_medium=inline-link&utm_campaign=newsletter-text&utm_content=upper-coronavirus-help">Read The Conversation’s newsletter</a>.]</p><img src="https://counter.theconversation.com/content/134762/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Inga Popovaite 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>Understanding isolation’s effects on regular people, rather than those certified to have ‘the right stuff,’ will help prepare us for the future, whether another pandemic or interplanetary space travel.Inga Popovaite, Ph.D. Candidate in Sociology, University of IowaLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1231712019-09-10T03:34:04Z2019-09-10T03:34:04ZIndia’s moon mission should be considered a success, and a lesson in spacefaring<p>Over the weekend, India attempted to make history by becoming just the fourth nation to successfully land a probe on the Moon. It came agonisingly close, but after journeying millions of kilometres, the Vikram lander lost contact in the final few hundred metres and crash-landed on the lunar surface.</p>
<p>But it would be both unfair and plain wrong to label the mission a failure.</p>
<h2>Two-month trip</h2>
<p>After a postponed launch, India’s Chandrayaan-2 spacecraft began its journey to the Moon on July 22. </p>
<p>Onboard it carried the Vikram lander and Pragyan rover, equipped to search the lunar south pole for water and other valuable resources. Everything seemed to be going according to plan. Chandrayaan-2 completed several orbits around Earth and then the Moon, slowly making its way closer to the lunar surface and taking photographs the whole time.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/291446/original/file-20190909-109915-fxfe7p.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/291446/original/file-20190909-109915-fxfe7p.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/291446/original/file-20190909-109915-fxfe7p.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/291446/original/file-20190909-109915-fxfe7p.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/291446/original/file-20190909-109915-fxfe7p.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=502&fit=crop&dpr=1 754w, https://images.theconversation.com/files/291446/original/file-20190909-109915-fxfe7p.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=502&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/291446/original/file-20190909-109915-fxfe7p.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=502&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Trajectory of the Chandrayaan 2 spacecraft.</span>
<span class="attribution"><span class="source">Source: Indian Space Research Organisation.</span></span>
</figcaption>
</figure>
<p>On September 2, the Vikram lander separated and began to make its descent. All communications were normal until the lander was within 2km of its goal. </p>
<p>Then it went silent – a space engineer’s worst nightmare. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/291454/original/file-20190909-109923-dak5dd.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/291454/original/file-20190909-109923-dak5dd.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=560&fit=crop&dpr=1 600w, https://images.theconversation.com/files/291454/original/file-20190909-109923-dak5dd.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=560&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/291454/original/file-20190909-109923-dak5dd.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=560&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/291454/original/file-20190909-109923-dak5dd.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=704&fit=crop&dpr=1 754w, https://images.theconversation.com/files/291454/original/file-20190909-109923-dak5dd.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=704&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/291454/original/file-20190909-109923-dak5dd.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=704&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Chandrayaan-2 Surveys the lunar surface.</span>
<span class="attribution"><span class="source">Indian Space Research Organisation</span></span>
</figcaption>
</figure>
<h2>Vikram, do you copy?</h2>
<p>So far, the Indian Space Research Organisation’s (ISRO) engineers have not been able to reestablish communications with the lander. It’s likely Vikram landed with enough force to damage its communications equipment, as well as other instruments. </p>
<p>But all hope was not lost, as Chandrayaan-2 remained in orbit above the Moon and, with its high-resolution camera, was able to spot the lander. If oriented favourably, Vikram could still manage to power itself up. </p>
<p>ISRO has not admitted defeat and will keep trying to connect to Vikram for the next two weeks. However, the chances of success diminish with time.</p>
<p>While the Chandrayaan-2 mission has not gone as expected, it cannot be called a failure. The <a href="https://nssdc.gsfc.nasa.gov/nmc/spacecraft/display.action?id=CHANDRYN2">Chandrayaan-2</a> orbiter will continue to monitor the Moon for up to seven years and the high-resolution images it takes will be vital to future international efforts to land on the Moon.</p>
<h2>Technically a success</h2>
<p>The near success of Vikram’s landing should be celebrated. To appreciate just how hard it is, let’s delve into some physics. </p>
<p>Earth is rotating and also hurtling through space at more than 100,000km per hour. The Moon is almost 400,000km away and travelling around 4,000km per hour as it orbits Earth. </p>
<p>To reach the Moon, you first have to escape Earth’s gravity and ensure you’re going at the right speed to orbit Earth a few times before moving far enough to be caught by the Moon. Then you slowly decrease your distance to the lunar surface, inching closer over several orbits until you are low enough to use powered assistance to land. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/india-has-it-right-nations-either-aim-for-the-moon-or-get-left-behind-in-the-space-economy-121497">India has it right: nations either aim for the Moon or get left behind in the space economy</a>
</strong>
</em>
</p>
<hr>
<p>It took the United States and Russia decades to design, plan and execute missions to the Moon. In fact, the ISRO was founded shortly after the successful Apollo 11 mission. </p>
<p>We should applaud the hard work India has done over the past 50 years to get this far. This sentiment was clear as Indian prime minister Narendra Modi <a href="https://www.space.com/india-prime-minister-chandrayaan-2-moon-landing-video-transcript.html">addressed</a> his country, all of whom stood in solidarity with the scientists who spent countless hours in pursuit of their goal.</p>
<h2>A global space community</h2>
<p>The story of the Indian lander echoes that of the <a href="https://theconversation.com/first-private-spacecraft-shoots-for-the-moon-109994">failed Israeli landing attempt</a> earlier this year. </p>
<p>The Beresheet lander was built by private company SpaceIL, which was chasing the coveted <a href="https://www.xprize.org/prizes/google-lunar">Google Lunar XPrize</a> when an engine malfunction caused it to swan dive into the Moon’s surface.</p>
<p>I mention this mission to reiterate just how hard the task is, but also to demonstrate that the old Cold War space superpowers are no longer the only ones in the game. Countries and even private companies across the world are gaining spacefaring capabilities and undertaking incredible missions that will enable humankind to go further than ever before. </p>
<p>In the next five years, more than a dozen missions to the Moon from six different countries, including Japan and Korea, are slated. This doesn’t include NASA’s ambitious <a href="https://www.nasa.gov/what-is-artemis">Artemis</a> mission that seeks to put the first woman on the Moon. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/five-reasons-india-china-and-other-nations-plan-to-travel-to-the-moon-87589">Five reasons India, China and other nations plan to travel to the Moon</a>
</strong>
</em>
</p>
<hr>
<p>But as the cliché goes, with great power comes great responsibility.</p>
<p>Now that countries across the world can send things into space, we must have solidarity as a global spacefaring community to consider how our actions up there will affect us on Earth and to ensure long-term success in space ventures. </p>
<p>This is not the last international space mission you will hear about in the news this year. </p>
<p>In coming years, we may even be discussing Australian ventures into space – and maybe even <a href="https://theconversation.com/australia-can-pick-up-its-game-and-land-a-moon-mission-121109">to the Moon itself</a>.</p><img src="https://counter.theconversation.com/content/123171/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Rebecca Allen does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Despite a last-minute crash-landing, efforts behind India’s moon mission should be applauded. The endeavor has set an example for emerging space programs across the globe.Rebecca Allen, Swinburne Space Office Project Coordinator | Manager Swinburne Astronomy Productions, Swinburne University of TechnologyLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1216022019-08-08T12:09:29Z2019-08-08T12:09:29ZTardigrades: we’re now polluting the moon with near indestructible little creatures<figure><img src="https://images.theconversation.com/files/287398/original/file-20190808-144868-10mhlpm.jpg?ixlib=rb-1.1.0&rect=0%2C157%2C3000%2C2070&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-illustration/tardigrade-water-bear-3d-rendered-illustration-535109380?src=cjaqEapOnY5_mpZ177xWvA-1-0">3DStock/Shutterstock</a></span></figcaption></figure><p>An Israeli spacecraft <a href="http://www.planetary.org/explore/space-topics/space-missions/beresheet.html">called Beresheet</a> almost made it to <a href="https://theconversation.com/uk/topics/moon-606">the moon</a> in April. It took a selfie with the lunar surface in the background, but then lost contact with Earth and presumably crashed onto the lunar surface. Now <a href="https://www.wired.com/story/a-crashed-israeli-lunar-lander-spilled-tardigrades-on-the-moon/">it’s been revealed</a> that the mission was carrying a cargo of dehydrated microscopic lifeforms known as tardigrades.</p>
<p>Beresheet was the first stage of a privately-funded initiative to <a href="https://www.archmission.org/">transfer living DNA to the moon</a>. The project is designed to act as Noah’s Ark Mark II, providing a repository from which plants and animals could be regenerated to repopulate the Earth should a catastrophe akin to a flood of biblical proportions overtake the planet.</p>
<p>Whether the project is far-sighted or foolish, what has roused interest is the fact that, as a result of the crash, the tardigrades may now be scattered across the lunar surface. They are hardy creatures and could probably survive on the moon for a long time. Is this a matter of concern? I believe so, but possibly not for the reasons you might think.</p>
<p>Tardigrades are <a href="https://www.livescience.com/57985-tardigrade-facts.html">odd little creatures</a>. Measuring up to about half a millimetre long, they have four pairs of stubby legs and a front-end that even the fondest parent couldn’t describe as beautiful. Striking, or distinctive, are my adjectives of choice. Moon-faced would be appropriate, given the context of the story – with a rounded, sucker-like structure in the centre that can project outwards, revealing a set of dangerous-looking sharp teeth. </p>
<p>They’re often called “water bears” but the images of tardigrades that I have seen remind me of a slightly over-inflated blimp, one of those large balloons that float overhead at carnivals. The legs stick out at a slight angle, as if they are too swollen to stand upright. And that is probably the clue as to why it is extremely unlikely that the creatures will survive indefinitely on the moon.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/287345/original/file-20190808-144868-1dp7qa3.jpg?ixlib=rb-1.1.0&rect=474%2C0%2C3610%2C2392&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/287345/original/file-20190808-144868-1dp7qa3.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=200&fit=crop&dpr=1 600w, https://images.theconversation.com/files/287345/original/file-20190808-144868-1dp7qa3.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=200&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/287345/original/file-20190808-144868-1dp7qa3.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=200&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/287345/original/file-20190808-144868-1dp7qa3.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=251&fit=crop&dpr=1 754w, https://images.theconversation.com/files/287345/original/file-20190808-144868-1dp7qa3.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=251&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/287345/original/file-20190808-144868-1dp7qa3.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=251&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
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<span class="caption">Tardigrades in space.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-illustration/tardigrade-vacuum-open-space-water-bear-726719797?src=cjaqEapOnY5_mpZ177xWvA-1-5">Dotted Yeti/Shutterstock</a></span>
</figcaption>
</figure>
<p>Tardigrades can survive extremes of temperature and pressure, including the frigid vacuum <a href="https://www.cell.com/current-biology/fulltext/S0960-9822(08)00805-1?_returnURL=https%3A%2F%2Flinkinghub.elsevier.com%2Fretrieve%2Fpii%2FS0960982208008051%3Fshowall%3Dtrue">of space</a>. They don’t seem to mind being <a href="https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0064793">exposed to radiation</a> and are all-round tough little creatures. When dehydrated, they roll up into a <a href="https://www.cell.com/biophysj/fulltext/S0006-3495(16)33630-X">spore-like state</a> that slows down their metabolic rate by about a hundred-fold, enabling them to survive for potentially <a href="https://zslpublications.onlinelibrary.wiley.com/doi/abs/10.1017/S095283690200078X">over 100 years</a>. </p>
<p>But to live their life to the fullest requires water. It’s where they get their oxygen and food, typically colonising clumps of algae or burrowing into sediment to ingest nutrients from the fluid of other living creatures, even other tardigrades. So while the tardigrades will technically stay alive on the moon for some length of time in their rolled-up state, unless they are rescued, rehydrated and refuelled, they will eventually perish.</p>
<h2>Interplanetary pollution</h2>
<p>I’m not concerned about polluting the moon with organisms that might reanimate. My concern is about polluting the moon, full stop. There is already a fairly sizeable <a href="https://www.theatlantic.com/technology/archive/2012/12/the-trash-weve-left-on-the-moon/266465/">amount of debris</a> from redundant spacecraft and litter left behind by astronauts. As more missions are planned to the moon, eventually with human passengers and perhaps even settlements, we must learn to clean up as we go along. Otherwise, we are going to have the sort of crisis that we are seeing on Earth with the outcry about environmental damage <a href="https://theconversation.com/uk/topics/plastic-pollution-52714">from plastics</a>. </p>
<p>There is, though, another question to consider. What if the spacecraft had crashed as it approached Mars rather than the moon? The planet has had a poor record for successful landings, although it is much improved in the past decade. Would the tardigrades have survived atmospheric entry? Even though the atmosphere of Mars is thin, it still provides sufficient resistance to cause serious damage to the outer shell of an entry vehicle.</p>
<p>If they had survived, would they ultimately be any more successfully on Mars than on the moon? We know there is plenty of ice below the immediate surface across much of the planet. Would an impacting spacecraft transfer sufficient energy to melt a local region of ice? Could that meltwater survive without sublimating away or refreezing for long enough that the tardigrades rehydrate and wake up?</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/287348/original/file-20190808-144878-1qq5a3.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/287348/original/file-20190808-144878-1qq5a3.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=601&fit=crop&dpr=1 600w, https://images.theconversation.com/files/287348/original/file-20190808-144878-1qq5a3.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=601&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/287348/original/file-20190808-144878-1qq5a3.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=601&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/287348/original/file-20190808-144878-1qq5a3.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=755&fit=crop&dpr=1 754w, https://images.theconversation.com/files/287348/original/file-20190808-144878-1qq5a3.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=755&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/287348/original/file-20190808-144878-1qq5a3.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=755&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">The surface of Mars should be kept pristine.</span>
<span class="attribution"><a class="source" href="https://www.nasa.gov/multimedia/imagegallery/image_feature_645.html">NASA</a></span>
</figcaption>
</figure>
<p>I have no idea, but let’s speculate that the answer to the two questions is “yes”, and that following a crash, a flock (herd? shoal? pack?) of tardigrades reactivates. What happens next? As detailed above, tardigrades need water to survive, not just to rehydrate them. They live on fluids derived from other living beings. And, as far as we know, there are no <a href="https://theconversation.com/uk/topics/life-on-mars-6975">living beings on Mars</a>. </p>
<p>But we still keep sending spacecraft to look for life. Sending a cargo of tardigrades to Mars would be irresponsible, even if we don’t believe they would survive. Irresponsible because Mars has the potential for life. Restricted life, for sure, but we have no right to endanger that life. And we have a responsibility to maintain Mars as close to pristine as possible, exploring it with care.</p>
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Read more:
<a href="https://theconversation.com/to-the-moon-and-beyond-podcast-series-trailer-119250">To the moon and beyond podcast series – Trailer</a>
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</p>
<hr>
<p>That is why space agencies take such stringent precautions about spacecraft construction. The rooms in which the craft are built are <a href="https://www.wired.com/story/inside-the-cleanroom-where-nasas-new-mars-lander-waits-to-launch/">cleaner and more sterile</a> than any operating theatre. They take every precaution to ensure that no terrestrial life is transferred to Mars.</p>
<p>NASA and ESA are currently planning a <a href="https://www.space.com/nasa-mars-sample-return-mission-2026.html">mission to return</a> samples from Mars to Earth. And precautions about the possibility of returning Martian life to Earth with the rocks are central to the design and build of the spacecraft.</p>
<p>Last week, we had an asteroid <a href="https://www.technologyreview.com/f/614027/a-huge-asteroid-flew-very-close-to-earth-last-week-how-did-we-miss-it/">passing close to the Earth</a>. Next week, maybe it will be killer bees. Or a plague of thieving magpies. But for now it is water bears on the moon. We should let them shrivel slowly into oblivion.</p><img src="https://counter.theconversation.com/content/121602/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Monica Grady is Professor of Planetary and Space Sciences at the Open University, and Research Fellow at the Natural History Museum, London. She receives funding from the STFC and the UK Space Agency. She is a Trustee of Lunar Mission One.</span></em></p>An Israeli spacecraft carrying tardigrades crashed into the moon. Whether they will survive is irrelevant.Monica Grady, Professor of Planetary and Space Sciences, The Open UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/761952017-04-21T20:30:02Z2017-04-21T20:30:02ZWater, weather, new worlds: Cassini mission revealed Saturn’s secrets<figure><img src="https://images.theconversation.com/files/166237/original/file-20170421-12662-1kfv8oj.jpg?ixlib=rb-1.1.0&rect=563%2C8%2C1718%2C1354&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Saturn and its rings backlit by the sun, which is blocked by the planet in this view. Encircling the planet and inner rings is the much more extended E-ring.</span> <span class="attribution"><span class="source">NASA/JPL/Space Science Institute</span>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span></figcaption></figure><p><a href="https://saturn.jpl.nasa.gov">Cassini</a> is the most sophisticated space probe ever built. Launched in 1997 as a joint NASA/European Space Agency mission, it took seven years to journey to Saturn. It’s been orbiting the sixth planet from the sun ever since, sending back data of immense scientific value and images of magnificent beauty.</p>
<p>Cassini has begun one last campaign. Dubbed <a href="https://saturn.jpl.nasa.gov/mission/grand-finale/overview/">the Grand Finale</a>, it will end on Sept. 15, 2017 with the probe plunging into Saturn’s atmosphere, where it will burn up. Although Saturn <a href="https://solarsystem.nasa.gov/missions/pioneer11/indepth">was visited</a> by <a href="http://voyager.jpl.nasa.gov">three spacecraft</a> in the 1970s and 1980s, <a href="https://saturn.jpl.nasa.gov/mission/team/">my fellow scientists and I</a> couldn’t have imagined what the Cassini space probe would discover during its sojourn at the ringed planet when it launched 20 years ago.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/166306/original/file-20170421-12645-14drs45.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/166306/original/file-20170421-12645-14drs45.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/166306/original/file-20170421-12645-14drs45.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=600&fit=crop&dpr=1 600w, https://images.theconversation.com/files/166306/original/file-20170421-12645-14drs45.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=600&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/166306/original/file-20170421-12645-14drs45.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=600&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/166306/original/file-20170421-12645-14drs45.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=754&fit=crop&dpr=1 754w, https://images.theconversation.com/files/166306/original/file-20170421-12645-14drs45.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=754&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/166306/original/file-20170421-12645-14drs45.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">A huge storm churning across the face of Saturn. At the time this image was taken, 12 weeks after the storm began, it had completely wrapped around the planet.</span>
<span class="attribution"><a class="source" href="https://saturn.jpl.nasa.gov/resources/5329/">NASA/JPL-Caltech/SSI</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
</figcaption>
</figure>
<h2>A planet of dynamic change</h2>
<p>Massive storms periodically appear in Saturn’s cloud tops, known as Great White Spots, observable by Earthbound telescopes. Cassini has a front-row seat to these events. We have discovered that just like Earth’s thunderstorms, these storms contain <a href="https://saturn.jpl.nasa.gov/resources/4943/">lightning</a> and hail. </p>
<p>Cassini has been orbiting Saturn long enough to observe seasonal changes that cause variations in its weather patterns, not unlike the seasons on Earth. Periodic storms often appear in late summer in Saturn’s northern hemisphere. </p>
<p>In 2010, during northern springtime, an unusually early and intense storm appeared in Saturn’s cloud tops. It was a storm of such immensity that it <a href="http://doi.org/10.1016/j.icarus.2012.12.013">encircled the entire planet</a> and lasted for almost a year. It was not until the storm ate its own tail that it eventually sputtered and faded. Studying storms such as this and comparing them to similar events on other planets (think Jupiter’s Great Red Spot) help scientists better understand weather patterns throughout the solar system, even here on Earth. </p>
<p>Having made hundreds of orbits around Saturn, Cassini was also able to deeply investigate other features only glimpsed from Earth or earlier probes. <a href="https://saturn.jpl.nasa.gov/mission/spacecraft/navigation/">Close encounters with Saturn’s largest moon, Titan</a>, have allowed navigators to use the moon’s gravity to reorient the probe’s orbit so that it could swing over Saturn’s poles. Because of <a href="https://saturn.jpl.nasa.gov/science/magnetosphere/">Saturn’s strong magnetic field</a>, the poles are home to <a href="https://saturn.jpl.nasa.gov/resources/4452/">beautiful Aurorae</a>, just like those of Earth and Jupiter.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/166304/original/file-20170421-22929-dgvpi6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/166304/original/file-20170421-22929-dgvpi6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/166304/original/file-20170421-22929-dgvpi6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=600&fit=crop&dpr=1 600w, https://images.theconversation.com/files/166304/original/file-20170421-22929-dgvpi6.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=600&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/166304/original/file-20170421-22929-dgvpi6.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=600&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/166304/original/file-20170421-22929-dgvpi6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=754&fit=crop&dpr=1 754w, https://images.theconversation.com/files/166304/original/file-20170421-22929-dgvpi6.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=754&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/166304/original/file-20170421-22929-dgvpi6.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">Saturn’s six-sided vortex at Saturn’s north pole known as ‘the hexagon.’ This is a superposition of images taken with different filters, with different wavelengths of light assigned colors.</span>
<span class="attribution"><span class="source">NASA/JPL-Caltech/SSI/Hampton University</span>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
</figcaption>
</figure>
<p>Cassini has also confirmed the existence of a bizarre <a href="https://saturn.jpl.nasa.gov/news/2509/nasas-cassini-spacecraft-obtains-best-views-of-saturn-hexagon/">hexagon-shaped polar vortex</a> originally glimpsed by the Voyager mission in 1981. The vortex, a mass of whirling gas much like a hurricane, is larger than the Earth and has top wind speeds of 220 mph. </p>
<h2>Home to dozens of diverse worlds</h2>
<p>Cassini discovered that Saturn has 45 more moons than the 17 previously known – placing the total now at 62.</p>
<p>The largest, <a href="https://saturn.jpl.nasa.gov/science/titan/">Titan</a>, is bigger than the planet Mercury. It possesses a dense nitrogen-rich atmosphere with a surface pressure one and a half times that of Earth’s. Cassini was able to probe beneath this moon’s cloud cover, discovering rivers flowing into lakes and seas and being replenished by rain. But in this case, the liquid is not water, but rather liquid methane and ethane.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/166307/original/file-20170421-22929-1ieknjz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/166307/original/file-20170421-22929-1ieknjz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/166307/original/file-20170421-22929-1ieknjz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=572&fit=crop&dpr=1 600w, https://images.theconversation.com/files/166307/original/file-20170421-22929-1ieknjz.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=572&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/166307/original/file-20170421-22929-1ieknjz.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=572&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/166307/original/file-20170421-22929-1ieknjz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=719&fit=crop&dpr=1 754w, https://images.theconversation.com/files/166307/original/file-20170421-22929-1ieknjz.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=719&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/166307/original/file-20170421-22929-1ieknjz.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=719&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">False-color image of Ligeia Mare, the second largest known body of liquid on Saturn’s moon Titan. It’s filled with liquid hydrocarbons.</span>
<span class="attribution"><a class="source" href="https://saturn.jpl.nasa.gov/news/2824/titan-flyby-t-93-monitoring-the-lakes/">NASA/JPL-Caltech/ASI/Cornell</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
</figcaption>
</figure>
<p>That’s not to say that water is not abundant there – but it’s so cold on Titan (with a surface temperature of -180°C) that water behaves like rock and sand. Although it has all the ingredients for life, Titan is essentially a “frozen Earth,” trapped at that moment in time before life could form.</p>
<p>The sixth-largest moon of Saturn, <a href="https://saturn.jpl.nasa.gov/science/enceladus/">Enceladus</a>, is an icy world about 300 miles in diameter. And for me, it’s the site of the Mission’s most spectacular finding.</p>
<p>The discovery started humbly, with a curious blip in magnetic field readings during the first flyby of Enceladus in 2004. As Cassini passed over the moon’s southern hemisphere, it detected strange fluctuations in Saturn’s magnetic field. From this, the Cassini magnetometer team inferred that Enceladus must be a source of ionized gas.</p>
<p>Intrigued, they instructed the Cassini navigators to make an even closer flyby in 2005. To our amazement, the two instruments designed to determine the composition of the gas that the spacecraft flies through, the <a href="https://saturn.jpl.nasa.gov/cassini-plasma-spectrometer/">Cassini Plasma Spectrometer (CAPS)</a> and the <a href="https://saturn.jpl.nasa.gov/ion-and-neutral-mass-spectrometer/">Ion and Neutral Mass Spectrometer (INMS)</a>, determined that Cassini was unexpectedly passing through a cloud of ionized water. Emanating from cracks in the ice at Enceladus’ south pole, these water plumes gush into space at speeds up to 800 mph. </p>
<p>I am on the team that made the <a href="https://doi.org/10.1126/science.1121061">positive identification of water</a>, and I have to say it was the most thrilling moment in my professional career. As far as Saturn’s moons were concerned, everyone thought all of the action would be at Titan. No one expected small, unassuming Enceladus to harbor any surprises.</p>
<p>Geologic activity happening in real time is quite rare in the solar system. Before Enceladus, the only known active world beyond Earth was <a href="http://www.space.com/16419-io-facts-about-jupiters-volcanic-moon.html">Jupiter’s moon Io</a>, which possesses erupting volcanoes. To find something akin to Old Faithful on a moon of Saturn was practically unimaginable. The fact that it all started with someone noticing an odd reading in the magnetic field data is a wonderful example of the serendipitous nature of discovery.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/166303/original/file-20170421-12650-nds7qd.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/166303/original/file-20170421-12650-nds7qd.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/166303/original/file-20170421-12650-nds7qd.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=350&fit=crop&dpr=1 600w, https://images.theconversation.com/files/166303/original/file-20170421-12650-nds7qd.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=350&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/166303/original/file-20170421-12650-nds7qd.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=350&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/166303/original/file-20170421-12650-nds7qd.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=439&fit=crop&dpr=1 754w, https://images.theconversation.com/files/166303/original/file-20170421-12650-nds7qd.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=439&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/166303/original/file-20170421-12650-nds7qd.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=439&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 geyser basin at the south pole of Enceladus, with its water plumes illuminated by scattered sunlight.</span>
<span class="attribution"><span class="source">NASA/JPL-Caltech/Space Science Institute</span>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
</figcaption>
</figure>
<p>The story of Enceladus only becomes more extraordinary. In 2009, the plumes were directly imaged for the first time. We now know that water from Enceladus comprises the largest component of Saturn’s magnetosphere (the area of space controlled by Saturn’s magnetic field), and the plumes are responsible for the very existence of Saturn’s vast <a href="https://saturn.jpl.nasa.gov/resources/3276/">E-ring</a>, the second outermost ring of the planet.</p>
<p>More amazingly, we now know that beneath the crust of Enceladus is a global ocean of liquid saltwater and organic molecules, all being heated by hydrothermal vents on the seafloor. Detailed analysis of the plumes show they contain hydrocarbons. All this points to the possibility that Enceladus is an ocean world harboring life, right here in our solar system. </p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/xrGAQCq9BMU?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">NASA at Saturn: Cassini’s Grand Finale.</span></figcaption>
</figure>
<p>When Cassini plunges into the cloud tops of Saturn later this year, it will mark the end of one of the most successful missions of discovery ever launched by humanity.</p>
<p>Scientists are now considering targeted missions to Titan, Enceladus or possibly both. One of the most valuable lessons one can take from Cassini is the need to continue exploring. As much as we learned from the first spacecraft to reach Saturn, nothing prepared us for what we would find with Cassini. Who knows what we will find next?</p><img src="https://counter.theconversation.com/content/76195/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Dan Reisenfeld receives funding from NASA. </span></em></p>With the probe now on its ‘Grand Finale,’ a Cassini team member describes the amazing discoveries it made about the ringed planet and its many moons.Dan Reisenfeld, Professor of Physics & Astronomy, University of MontanaLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/410152015-04-30T14:56:26Z2015-04-30T14:56:26ZRussian spacecraft falling to Earth poses no danger – we have survived bigger objects<p>A Russian spacecraft is <a href="http://www.theguardian.com/science/2015/apr/29/unmanned-russian-spacecraft-iss-plunging-to-earth-says-official">spinning uncontrollably</a> around Earth after it broke down travelling to the International Space Station with food and fuel supplies. The vessel, Progress M-27M, will burn up when re-entering the Earth’s atmosphere in <a href="https://www.youtube.com/watch?v=8dQ2mUIieQQ&app=desktop">a week or two</a>, although there is a small chance that parts of it could crash down on the planet. The risk to us humans is minute – we have survived far greater objects falling back towards Earth before.</p>
<p>The <a href="https://www.nasa.gov/mission_pages/station/main/index.html">six people</a> currently at the ISS are not in any great danger of running out of food either, as the next supply vessel is scheduled to dock at the ISS on June 19 – long before its current <a href="http://www.welt.de/wirtschaft/article140267666/Russischer-Raumfrachter-stuerzt-Richtung-Erde.htmlhttp://www.welt.de/wirtschaft/article140267666/Russischer-Raumfrachter-stuerzt-Richtung-Erde.html">food supply is due to run out</a> in September.</p>
<h2>The problem with Progress</h2>
<p>Progress M-27M launched on April 28 but soon started developing some serious problems. It was not inserted into the correct orbit and ended up in what was described as an “emergency state” when detaching from the rocket used to bring it into orbit. It has only been able to establish limited communication and control with the ground.</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/9VmzMP2aKQI?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">Progress breaks down and starts tumbling. NASA.</span></figcaption>
</figure>
<p>At the moment the module is in a low safe orbit that does not <a href="https://theconversation.com/space-debris-what-can-we-do-with-unwanted-satellites-40736">endanger any other satellites</a> or the ISS. The module was designed to burn up in high atmosphere after supplying the ISS and being filled with rubbish from the station. </p>
<p>As long as the engineers in Russia manage to control its path there should be no danger of the vessel reaching Earth’s surface. The problem is that since there is very limited control of the vessel at the moment, there might be a slim chance that some parts of the craft might not fully burn up. Because the majority of out planet is filled with oceans and sparsely populated areas, the probability of parts actually hitting people is tiny, however the risk cannot be reliably calculated at the moment since the trajectory of the time of re-entry is not yet clear. But if the conditions are the same as were for <a href="http://www.nasa.gov/mission_pages/uars/">NASA’s Upper Atmosphere Research Satellite</a>, which fell back to Earth in September 2011, <a href="http://m.livescience.com/33511-falling-nasa-satellite-uars-risk.html">the probability</a> of hitting any human would be one in 3,200.</p>
<p>A more pressing matter might be that the six-person ISS crew run out of food. However, not only is the next supply vessel <a href="http://www.spacex.com/dragon">DragonX</a> scheduled <a href="https://www.youtube.com/watch?v=8dQ2mUIieQQ&app=desktop">to dock</a> at the ISS on June 19, there will also be a larger Japanese supply vessel arriving in mid-August. In the worst case scenario of no supply reaching the station, the ISS astronauts would run out of food by September 5, with a system of rationing in place from July 24. Water would run out by mid-September. Handily, the ISS has a permanently docked module that would allow the team to return safely to Earth. So overall the crew has only to put up with a delay in delivery of equipment and supplies.</p>
<h2>Lessons from the past</h2>
<p>Looking back into history there have been far greater objects re-entering Earth’s atmosphere and we have survived such events without tidal waves occurring or being cast into a nuclear winter. The 150-tonne <a href="http://history.nasa.gov/SP-4225/mir/mir.htm">MIR space station</a> burnt up in 2001. The result? A few tourists on the remote Fiji islands captured some nice holiday snaps of fragments and heard sonic booms. The 77-tonne <a href="http://www.history.com/news/the-day-skylab-crashed-to-earth-facts-about-the-first-u-s-space-stations-re-entry">Skylab</a> re-entered 1979 over the Indian Ocean without much ado. The Progress module weighs in at only approximately ten tonnes and none of its material is classed as dangerous. Therefore issues as arising from the <a href="http://web.archive.org/web/20110929125210/http://gsc.nrcan.gc.ca/gamma/ml_e.php">Cosmos 954 crash</a> in Canada in 1977 with radioactive debris is not expected either.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/79916/original/image-20150430-6271-ixn98t.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/79916/original/image-20150430-6271-ixn98t.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=604&fit=crop&dpr=1 600w, https://images.theconversation.com/files/79916/original/image-20150430-6271-ixn98t.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=604&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/79916/original/image-20150430-6271-ixn98t.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=604&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/79916/original/image-20150430-6271-ixn98t.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=759&fit=crop&dpr=1 754w, https://images.theconversation.com/files/79916/original/image-20150430-6271-ixn98t.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=759&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/79916/original/image-20150430-6271-ixn98t.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=759&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">We survived MIR crashing – and it was way bigger!</span>
<span class="attribution"><a class="source" href="http://history.nasa.gov/SP-4225/sts86/photo/sts-86-photo-65.htm">NASA</a></span>
</figcaption>
</figure>
<p>The main lesson learnt from this incident is that when it comes to space flight and even unmanned supply missions you always have to plan for the unexpected. The next step would be now a detailed analysis of why Progress failed, especially since the rocket and module are similar to the ones used for manned missions carried out by the Russians. If it takes too long to establish the cause, it might <a href="http://www.history.com/news/the-day-skylab-crashed-to-earth-facts-about-the-first-u-s-space-stations-re-entry">cause a delay</a> to the next scheduled Russian manned mission on May 26.</p>
<p>The problem also shows why international collaboration is essential for ensuring the safety of the ISS crew and the successful performance of a space station – and why these ties should be strengthened for future space ventures.</p><img src="https://counter.theconversation.com/content/41015/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Daniel Brown receives funding from STFC, IoP, Royal Astronomical Society and !Ignite. However his views are his own and do not represent those of the STFC.</span></em></p>Russian space vessel Progress M-27M is falling towards Earth but what risk does it pose?Daniel Brown, Lecturer in Astronomy, Nottingham Trent UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/391182015-04-05T22:49:12Z2015-04-05T22:49:12ZThe pale blue dot and other ‘selfies’ of Earth<figure><img src="https://images.theconversation.com/files/75632/original/image-20150323-26729-1ocuw8j.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Pale Blue Dot -- Earth, imaged by Voyager 1 from 6 billion kilometres away.</span> <span class="attribution"><a class="source" href="https://solarsystem.nasa.gov/multimedia/display.cfm?IM_ID=2148">NASA.</a></span></figcaption></figure><p>Twenty-five years ago a set of images were taken that provided a unique view of Earth and helped highlight the fragility of our existence, and the importance of our stewardship.</p>
<p>As the <a href="https://theconversation.com/au/topics/voyager">Voyager 1</a> planetary spacecraft went beyond the orbit of Pluto on February 14, 1990, it took one last look at Earth. Three exposures, each one in a different filter, contained a very small and faint Earth.</p>
<p>The images were then stored on-board, on a tape recorder but because of competing planetary missions the data took until May 1990 to arrive back on Earth.</p>
<p>Despite Voyager 1 being more than 6 billion kilometres from Earth, the three exposures ranged only between 0.48 and 0.72 seconds in duration. But the data took five and a half hours, travelling at the speed of light, to span the distance between the spacecraft and Earth.</p>
<h2>A ‘selfie’ of Earth</h2>
<p>Three images (separately in blue, green and violet light) were combined to produce the now famous Pale Blue Dot image, Voyager 1’s “selfie” of Earth.</p>
<p>It is an image that contains all of Earth and yet <a href="http://visibleearth.nasa.gov/view.php?id=52392">NASA says</a> Earth was a crescent at the time and only 0.12 of one pixel in size.</p>
<p>Earth has a blue appearance due to reflected light scattering off oceans, clouds and land. The faint band of light in which it is seemingly suspended is not some celestial filament but an artifact of scattered sunlight.</p>
<p>Pale Blue Dot was part of a remarkable larger “<a href="http://www.planetary.org/multimedia/space-images/charts/solar-system-family-portrait.html">family</a>” portrait of the solar system, an idea the famous American astronomer Carl Sagan, a member of the Voyager imaging team, came up with many years before 1990.</p>
<p>Despite our planet being so small, the image has a strangely magical quality in which for the first time we can begin to appreciate our place, not only in the much larger solar system, but in the galaxy we reside, that is part of our universe.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/75596/original/image-20150323-14630-1t8g4so.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/75596/original/image-20150323-14630-1t8g4so.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/75596/original/image-20150323-14630-1t8g4so.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=475&fit=crop&dpr=1 600w, https://images.theconversation.com/files/75596/original/image-20150323-14630-1t8g4so.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=475&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/75596/original/image-20150323-14630-1t8g4so.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=475&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/75596/original/image-20150323-14630-1t8g4so.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=596&fit=crop&dpr=1 754w, https://images.theconversation.com/files/75596/original/image-20150323-14630-1t8g4so.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=596&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/75596/original/image-20150323-14630-1t8g4so.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=596&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">These six narrow-angle colour images were made from the first ever.
‘portrait’ of the solar system taken by Voyager 1.</span>
<span class="attribution"><a class="source" href="http://nssdc.gsfc.nasa.gov/photo_gallery/photogallery-solarsystem.html">NASA, Voyager 1</a></span>
</figcaption>
</figure>
<p>Our Earth dot is not distinguishable from the other dots in the larger solar system portrait. </p>
<p>Yet, it is of course special. For one thing, in 1977 we launched a spacecraft called Voyager 1 from that dot.</p>
<p>Sagan titled his 1994 book <a href="https://www.goodreads.com/book/show/61663.Pale_Blue_Dot">Pale Blue Dot: A Vision of the Human Future in Space</a> after the image, and in it he said:</p>
<blockquote>
<p>Our posturings, our imagined self-importance, the delusion that we have some privileged position in the universe, are challenged by this point of pale light.</p>
</blockquote>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/wupToqz1e2g?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
</figure>
<h2>Other ‘selfies’ of Earth</h2>
<p>The Pale Blue Dot was not the first image of Earth taken from space. On Christmas Eve 1968, Apollo 8 astronauts William Anders, James Lovell and Frank Borman were in lunar orbit and took several images of an Earth rising above the moon’s horizon.</p>
<p>One image in particular – known as Earthrise – has resonated like the Pale Blue Dot.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/75607/original/image-20150323-14609-1x0mv4q.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/75607/original/image-20150323-14609-1x0mv4q.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/75607/original/image-20150323-14609-1x0mv4q.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/75607/original/image-20150323-14609-1x0mv4q.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/75607/original/image-20150323-14609-1x0mv4q.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/75607/original/image-20150323-14609-1x0mv4q.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/75607/original/image-20150323-14609-1x0mv4q.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/75607/original/image-20150323-14609-1x0mv4q.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Earthrise.</span>
<span class="attribution"><a class="source" href="https://www.nasa.gov/multimedia/imagegallery/image_feature_1249.html#.VQ9lO_l9J2A">NASA</a></span>
</figcaption>
</figure>
<p>The image of a hemispherically illuminated blue sea, white cloud (with traces of brown land) Earth seemingly floating above the lunar horizon as the astronauts orbited the moon, is iconic.</p>
<p>The Earth was too small to easily identify known features. Craters and other features of the moon’s surface clearly show that the photographers had left their home.</p>
<p>You can watch a recreation of the time in the mission when the images were taken in this video (below).</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/dE-vOscpiNc?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
</figure>
<p>Apollo astronauts, the first to journey to the moon, were also the first humans to take images of the whole Earth. At such distances, at least in the daylight part, cities and evidence of humans are invisible.</p>
<p>Apollo 8 command module pilot Jim Lovell, picturing himself as a first-time Earth visitor, <a href="http://www.hq.nasa.gov/pao/History/SP-4205/ch11-6.html">commented</a> to his mission commander Frank Borman:</p>
<blockquote>
<p>Frank, what I keep imagining is if I am some lonely traveller from another planet what I would think about the Earth at this altitude, whether I think it would be inhabited or not […] I was just curious if I would land on the blue or brown part of the Earth.</p>
</blockquote>
<p>In December 1972, only four years after Apollo 8, the Apollo 17 crew took one of the most famous and widely used whole-Earth images from a distance of 45,000km on its outbound leg, dubbed the “The Blue Marble” for obvious reasons.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/75612/original/image-20150323-14609-13syqje.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/75612/original/image-20150323-14609-13syqje.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/75612/original/image-20150323-14609-13syqje.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=600&fit=crop&dpr=1 600w, https://images.theconversation.com/files/75612/original/image-20150323-14609-13syqje.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=600&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/75612/original/image-20150323-14609-13syqje.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=600&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/75612/original/image-20150323-14609-13syqje.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=754&fit=crop&dpr=1 754w, https://images.theconversation.com/files/75612/original/image-20150323-14609-13syqje.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=754&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/75612/original/image-20150323-14609-13syqje.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 Blue Marble.</span>
<span class="attribution"><a class="source" href="http://earthobservatory.nasa.gov/IOTD/view.php?id=1133">NASA</a></span>
</figcaption>
</figure>
<p>Similar whole-Earth images had been taken as early as 1967 by satellites but the Blue Marble combines human photographer, a unique alignment of sun, spacecraft and Earth and the most artistic (even abstract!) mix of land, ocean and cloud.
This combination has elevated this image above many similar ones. It is an Earth we know. </p>
<h2>The human ‘selfie’ in space</h2>
<p>The first human selfie in space – which also includes Earth – was seemingly taken by Edwin “Buzz” Aldrin in 1966 during the Gemini 12 mission. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/75626/original/image-20150323-26733-1yogiqf.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/75626/original/image-20150323-26733-1yogiqf.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/75626/original/image-20150323-26733-1yogiqf.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=540&fit=crop&dpr=1 600w, https://images.theconversation.com/files/75626/original/image-20150323-26733-1yogiqf.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=540&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/75626/original/image-20150323-26733-1yogiqf.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=540&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/75626/original/image-20150323-26733-1yogiqf.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=679&fit=crop&dpr=1 754w, https://images.theconversation.com/files/75626/original/image-20150323-26733-1yogiqf.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=679&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/75626/original/image-20150323-26733-1yogiqf.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=679&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Edwin ‘Buzz’ Aldrin during the Gemini 12 mission in 1966.</span>
<span class="attribution"><a class="source" href="http://spaceflight.nasa.gov/gallery/images/gemini/gemini12/html/s66-62926.html">NASA</a></span>
</figcaption>
</figure>
<p>Note that this was taken while in a bulky spacesuit, wearing thick gloves, pre-smartphone and many years before the common use of the <a href="http://en.wikipedia.org/wiki/Selfie_stick">selfie-stick</a>.</p>
<p>Selfies of International Space Station (ISS) residents and even ISS spacewalkers appear regularly in social media and these images now seem to be somewhat expected and slightly mundane.</p>
<p><div data-react-class="Tweet" data-react-props="{"tweetId":"577169264114728960"}"></div></p>
<p>Not to be outdone, machines have joined the quest for self reflection. As far back as 1976 the Viking 2 lander on Mars took partial self-portraits, containing part of the lander with the Martian horizon in the background.</p>
<p>In 2013, also on Mars, NASA’s Curiosity rover took 66 high-resolution images, which together made this wonderful self-portrait. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/75628/original/image-20150323-26733-8jh8jr.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/75628/original/image-20150323-26733-8jh8jr.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/75628/original/image-20150323-26733-8jh8jr.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=462&fit=crop&dpr=1 600w, https://images.theconversation.com/files/75628/original/image-20150323-26733-8jh8jr.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=462&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/75628/original/image-20150323-26733-8jh8jr.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=462&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/75628/original/image-20150323-26733-8jh8jr.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=581&fit=crop&dpr=1 754w, https://images.theconversation.com/files/75628/original/image-20150323-26733-8jh8jr.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=581&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/75628/original/image-20150323-26733-8jh8jr.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=581&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">A self-portrait of NASA’s Mars rover Curiosity.</span>
<span class="attribution"><a class="source" href="http://photojournal.jpl.nasa.gov/catalog/PIA16763">NASA/JPL-Caltech/MSSS</a></span>
</figcaption>
</figure>
<p>But selfies of robots do not strongly resonate with me. What strikes me the most are images of Earth taken by us or our machines. Whether it is from high orbit, en route to the moon, from another part of the solar system or even from outside the solar system, our ability to take images of our planet has changed our perspective forever. It is us we are looking back upon. </p>
<p>Most of the Apollo astronauts commented that their original mission objective was the moon, yet their biggest impact came from viewing the (their) Earth. </p>
<p>Some 40 years after his mission to the moon, Apollo 8’s William (Bill) Anders told a television documentary that:</p>
<blockquote>
<p>It’s tiny out there […] it’s inconsequential. It’s ironic that we had come to study the moon and it was really discovering the Earth.</p>
</blockquote>
<p>In the near future the images taken during Apollo will be joined by images of Earth taken from human travellers to, and residents of Mars.</p>
<p>In the short term though the Pale Blue Dot will not be matched in the impact and reaction it creates.</p>
<p>In that one dot is our 5 billion year old planet with its unique mix of favourable position from the sun, liquid water, tectonic activity, thin atmosphere, life and unique flora and fauna.</p>
<p>It represents all human history, our discoveries, our evolved intellect, our social achievements, our destructive wars, our families and loved ones, all those before us and the current seven billion humans and rising, in lockstep with increasing environmental and resources impact.</p>
<h2>Beyond the Pale Blue Dot</h2>
<p>Voyager 1 is now more than 19 billion kilometres from Earth. It has travelled 13 billion kilometres in the 25 years since since taking the original Pale Blue Dot. Even if the camera that took the image could be brought back to life, it is unlikely a similar set of images would detect Earth. </p>
<p>From the more distant Voyager 1 perspective Earth is both fainter by a factor of ten and closer to a still bright sun.</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/L4hf8HyP0LI?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
</figure>
<p>Voyager 1 is now regarded as being in <a href="https://theconversation.com/voyager-1-is-leaving-the-solar-system-but-the-journey-continues-11184">interstellar space</a>, as it is outside the influence of our sun and is travelling toward the constellation Ophiuchus. In the year 40,272 AD, Voyager 1’s <a href="http://www.space.com/22783-voyager-1-interstellar-space-star-flyby.html">next encounter</a> will be to come within 1.7 light years of a star in the constellation Ursa Minor called AC+79 3888.</p>
<p>What will Earth look like in 40,272 AD? More importantly, what will Earth look like in 4027 AD, only slightly more than 2,000 years from now? Will future spacecraft over the next 2,000 years take as potent images as Pale Blue Dot, Earthrise or the Blue Marble? </p>
<p>Apollo showed a recognisable but seemingly fragile home planet. Voyager 1 showed an unremarkable dot much like several others in our star’s planetary system. Has the evolving Earth “selfie” changed our behaviour?</p>
<p>Human selfies are often perceived as having a negative narcissistic component. The Earth “selfie” has only positive attributes.</p>
<p>A century ago, the famous naturalist John Muir seemed to anticipate the Earth “selfie” when he wrote in his book <a href="https://www.goodreads.com/book/show/453231.Travels_in_Alaska">Travels in Alaska</a>:</p>
<blockquote>
<p>[…] when we contemplate the whole globe as one great dewdrop, striped and dotted with continents and islands, flying through space with other stars all singing and shining together as one, the whole universe appears as an infinite storm of beauty.</p>
</blockquote>
<p>Such self-portraits of Earth should make us continually ask are we worthy stewards to help navigate our home through John Muir’s stormy yet beautiful universe?</p><img src="https://counter.theconversation.com/content/39118/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Glen Mackie does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>From a big blue marble to a tiny dot in space – reflections on our images of Earth.Glen Mackie, Senior Lecturer in Astronomy & Astrophysics, Coordinator of Swinburne Astronomy Online, Swinburne University of TechnologyLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/355092014-12-19T06:16:33Z2014-12-19T06:16:33ZAfter Rosetta, Japanese mission aims for an asteroid in search of origins of Earth’s water<p>The <a href="http://www.esa.int/ESA">European Space Agency</a>’s <a href="http://www.esa.int/Our_Activities/Space_Science/Rosetta">Rosetta mission</a> to land on comet 67P was one of the most audacious in space history. The idea of landing on a small chunk of icy rock 300m kilometres away from Earth and hurtling towards the sun at speeds approaching 135,000km/hour is incredible – made more so by the fact they <a href="http://www.bbc.co.uk/news/live/science-environment-29985988">actually achieved it</a>.</p>
<p>What scientists have learned from the data returned by Rosetta supports the need for another ambitious space mission that has just begun: the Japanese Aerospace Exploration Agency (JAXA) <a href="http://www.jspec.jaxa.jp/e/activity/hayabusa2.html">Hayabusa2</a> mission will intercept not a comet, but an asteroid, landing on its surface no fewer than three times.</p>
<p>Data returned by the Rosetta mission has already provided us with many surprises, including <a href="http://www.sciencemag.org/content/early/2014/12/09/science.1261952">the results now published</a> in the journal Science, which reveal that the nature of the water found on comet 67P does not match that found on Earth. </p>
<p>Examining the vaporous cloud that encloses the comet nucleus, Rosetta measured the ratio of hydrogen to its heavier form, <a href="http://www.britannica.com/EBchecked/topic/159684/deuterium">deuterium</a>, and found it was <a href="http://www.esa.int/Our_Activities/Space_Science/Rosetta/Rosetta_fuels_debate_on_origin_of_Earth_s_oceans">three times higher</a> than that found on Earth. This is an important discovery, since while water is vital to our existence on Earth, it is not at all obvious where it came from.</p>
<h2>In the beginning</h2>
<p>The Earth was formed from small rocky <a href="http://www.britannica.com/EBchecked/topic/463084/planetesimal">planetesimals</a> that circled the young sun, coalescing into a planet that was most likely born a dry world. Ices are not found in the planetary formation process until we reach lower temperatures much further out into the solar system. This means that the Earth must have had a water delivery at a later time.</p>
<p>One hypothesis is that water came via <a href="https://solarsystem.nasa.gov/faq/index.cfm?Category=Comets#q3">comet impacts</a>. Comets are formed in the chilly reaches around the giant planets of Jupiter, Saturn, Uranus and Neptune and are heavy in ice. During the end of our solar system’s formation, a large number of these were scattered towards the inner planets via gravitational kicks from their mammoth planetary neighbours. Striking our dry world, their icy contents could have begun the formation of our oceans. </p>
<p>But Rosetta’s analysis of comet 67P suggests that our oceans are not filled with fresh comet water. What we need is an alternative source, which leads us to Hayabusa2’s mission to the asteroids. </p>
<h2>Answers from asteroids</h2>
<p>The <a href="http://spaceflightnow.com/2014/12/03/hayabusa-2-launches-on-audacious-asteroid-adventure/">JAXA Hayabusa2</a> mission, which launched in early December, aims to intercept <a href="http://iopscience.iop.org/1538-3881/146/2/26">asteroid 1999 JU3</a>, touch down on its surface three times, deploy a lander with a trio of rovers and return to Earth with the asteroid samples in 2020. In short, it is a worthy successor to Rosetta. </p>
<p>Both comets and asteroids are left-over rocky parts from the planet formation process, but asteroids sit much closer to the Earth. The majority form a band orbiting the sun beyond Mars, known as the <a href="http://space-facts.com/asteroid-belt/">asteroid belt</a>, but Hayabusa2’s target is far closer, currently orbiting the sun between the Earth and Mars. </p>
<p>Asteroids come in <a href="http://www.astronomysource.com/tag/s-type-asteroids/">different flavours</a>. The S-type group have been heated during their lifetime in processes that alter their original composition, while C-type asteroids – the target of Hayabusa2 – are thought to have changed very little since their original formation. </p>
<p>As its name implies, Hayabusa2 has a predecessor that visited the S-type asteroid, <a href="http://global.jaxa.jp/article/special/hayabusa_sp3/index_e.html">Itokawa</a>, which showed evidence of experiencing heating up to 800°C. While its exploration illuminated much about the evolution of such space rocks, it held no answers as to the arrival of water on Earth.</p>
<h2>Answers in clay</h2>
<p>At only around 1km across, 1999 JU3 has insufficient gravity to hold liquid water, but observations suggest it contains clays, which require water to form. This, and its current unstable orbit, implies that it was once part of a larger object that broke apart.</p>
<p>After completing an initial analysis, Hayabusa2’s first touchdown will be at the site of the discovered clays. While Rosetta deployed a lander to reach the comet surface, Hayabusa2 will itself make contact with the asteroid, firing a bullet as it descends to break up surface material that it can gather. It will do this twice more at different locations; the third descent will preceded by the firing of a larger missile to bring up rocky debris from beneath the surface of the asteroid. While making a direct landing is risky, the advantage is that these samples can be brought back to Earth for thorough analysis. </p>
<p>Despite touching down itself, Hayabusa2 will also deploy a lander. Developed by the same German and French teams that built the Rosetta lander, Philae, Hayabusa2’s MASCOT (<a href="http://www.dlr.de/irs/en/desktopdefault.aspx/tabid-5960/10970_read-34316/">Mobile Asteroid Surface SCout</a>) will run on a 15-hour battery and dispatch three small rovers to explore the surface. </p>
<h2>Life’s building blocks in space</h2>
<p>However, water may be only one part of the secrets to be discovered on 1999 JU3. Previous <a href="http://www.newscientist.com/article/dn22127-meteorites-lefthanded-molecules-a-blow-to-et-search.html">research has suggested</a> that reactions with water on asteroids are linked to the production of amino acids: the organic building blocks for life. Not only this, but these amino acids seem to be predominantly <a href="http://www.nasa.gov/topics/solarsystem/features/life-turned-left.html">left-handed</a>; a distinctive feature of those in life on Earth.</p>
<p>While amino acids created in the laboratory appear equally as both left- and right-handed mirror images, biology strongly favours the left-handed version. We don’t know the reason for this preference, making the suggestion that such selectivity could have begun in space extremely exciting. If this turns out to be true, then scientists opening Hayabusa2’s sample jar in six years time may not only find the source of our water, but perhaps also the very beginnings of life.</p><img src="https://counter.theconversation.com/content/35509/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Elizabeth Tasker does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>The European Space Agency’s Rosetta mission to land on comet 67P was one of the most audacious in space history. The idea of landing on a small chunk of icy rock 300m kilometres away from Earth and hurtling…Elizabeth Tasker, Assistant Professor, Hokkaido UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/354112014-12-11T19:54:41Z2014-12-11T19:54:41ZRosetta is making a splash again, but results show comet’s water not the same as Earth’s<figure><img src="https://images.theconversation.com/files/67032/original/image-20141211-6030-1axqbpx.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">images taken by Rosetta’s navigation camera on December 7 from a distance of 19.7 km from the centre of Comet 67P/Churyumov-Gerasimenko.</span> <span class="attribution"><a class="source" href="http://www.esa.int/var/esa/storage/images/esa_multimedia/images/2014/12/comet_on_7_december_2014_navcam/15105534-1-eng-GB/Comet_on_7_December_2014_NavCam.jpg">ESA</a>, <span class="license">Author provided</span></span></figcaption></figure><p>The <a href="http://www.nytimes.com/2014/12/11/science/rosetta-mission-data-rules-out-comets-as-a-source-for-earths-water.html?_r=0">first results on comet 67P Churyumov-Gerasimenko</a> obtained by instruments on-board the Rosetta spacecraft have been announced – and they are, literally and figuratively, a deluge of information!</p>
<p>Over the past few months, the navigation cameras have provided us with amazing pictures of the surface of comet 67P. As <a href="https://theconversation.com/before-the-historic-comet-landing-philae-faces-many-dangers-32230">the Rosetta spacecraft approached</a>, the nucleus was revealed in increasing detail, as having a complex landscape of craters and plains, intersected by canyons and crevasses. Interest focused on the Philae lander <a href="https://theconversation.com/how-rosetta-made-an-epic-journey-through-space-and-overcame-incredible-challenges-34162">and whether or not it would land safely</a> on this hazardous surface. </p>
<p>Meanwhile, patiently and systematically, almost a dozen scientific instruments on the mother-craft were busy acquiring data on the temperature and density of the cometary nucleus, the gas and dust streaming away from it, its radio and plasma environment and the variation in composition of its surface. Many of these data were used to build up a picture of 67P, so that its rotation and gravitational pull could be calculated more accurately to enable Philae’s landing site to be pinpointed with greater precision. </p>
<p>As<a href="https://theconversation.com/scientists-at-work-from-rosetta-mission-control-as-philae-lands-34152"> we saw in November</a>, thanks to the Rosetta data, Philae touched down exactly where it was predicted to arrive. It was technical problems with the thruster and harpoons that <a href="https://theconversation.com/philae-on-comet-67p-but-all-is-not-well-34098">caused the lander to go astray</a>.</p>
<p>Now the data acquired by instruments on Rosetta are coming into their own, and the first insights to comet 67P’s ancestry have been published. ROSINA (Rosetta Orbiter Spectrometer for Ion and Neutral Analysis) has been acquiring mass spectra from the comet since early August, when Rosetta was around 100 km away. The report, by Kathrin Altwegg and colleagues <a href="http://www.sciencemag.org/content/early/2014/12/09/science.1261952">in the journal Science</a>, concerns the ratio of deuterium to hydrogen (D/H) in water in the comet’s coma. They have found this to be about three times the value of water on the Earth.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/67030/original/image-20141211-6042-1qle6ci.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/67030/original/image-20141211-6042-1qle6ci.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/67030/original/image-20141211-6042-1qle6ci.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=375&fit=crop&dpr=1 600w, https://images.theconversation.com/files/67030/original/image-20141211-6042-1qle6ci.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=375&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/67030/original/image-20141211-6042-1qle6ci.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=375&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/67030/original/image-20141211-6042-1qle6ci.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=472&fit=crop&dpr=1 754w, https://images.theconversation.com/files/67030/original/image-20141211-6042-1qle6ci.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=472&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/67030/original/image-20141211-6042-1qle6ci.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=472&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Results from Rosetta’s ROSINA instrument finds water on 67P quite different to that on Earth.</span>
<span class="attribution"><a class="source" href="http://www.sciencemag.org/content/early/2014/12/09/science.1261952">ESA</a>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>Why is this important? One of the main goals of the Rosetta mission is to uncover <a href="http://www.bbc.co.uk/news/science-environment-30414519">any relationship</a> between water in comets and water on Earth. When the Earth first formed, its surface was molten and it lost a large proportion of its volatiles (water, carbon dioxide, etc.). The Earth that we know today must have acquired a new reservoir of these materials – but from where? </p>
<p>Comets, <a href="http://www.space.com/16144-kuiper-belt-objects.html">Kuiper Belt Objects</a> and asteroids are all potential sources. Results from ROSINA have been interpreted as indicating that the family of comets to which 67P belongs (Jupiter Family Comets) is not solely responsible for delivery of volatiles to Earth. The report infers that asteroids played a greater role in the delivery process than previously anticipated.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/67031/original/image-20141211-6051-hvlxb2.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/67031/original/image-20141211-6051-hvlxb2.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/67031/original/image-20141211-6051-hvlxb2.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=338&fit=crop&dpr=1 600w, https://images.theconversation.com/files/67031/original/image-20141211-6051-hvlxb2.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=338&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/67031/original/image-20141211-6051-hvlxb2.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=338&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/67031/original/image-20141211-6051-hvlxb2.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=424&fit=crop&dpr=1 754w, https://images.theconversation.com/files/67031/original/image-20141211-6051-hvlxb2.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=424&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/67031/original/image-20141211-6051-hvlxb2.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=424&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Kuiper Belt and Oort Cloud - believed to be the two main reservoirs for comets in the Solar System.</span>
<span class="attribution"><a class="source" href="http://www.esa.int/var/esa/storage/images/esa_multimedia/images/2014/12/kuiper_belt_and_oort_cloud_in_context/15106869-1-eng-GB/Kuiper_Belt_and_Oort_Cloud_in_context.jpg">ESA</a>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<h2>Water everywhere but not a drop to drink</h2>
<p>Where does this leave us? For one thing, we have to understand what the elevated D/H ratio means for the ancestry of the comet. To contain so much deuterium implies that the comet has a high proportion of interstellar water – it is indeed an amalgam of primitive material that has not been changed during its 4.5 billion year history. </p>
<p>And this leads us on to the other components of the comet, particularly organic compounds, the carbon-bearing molecules which are so abundant in the clouds from which comets form, and also which act as the building blocks of life. ROSINA has not yet reported any carbon data – but almost certainly will be doing so. Both the <a href="http://blogs.esa.int/rosetta/2014/12/02/the-quest-for-organic-molecules-on-the-surface-of-67pc-g/">Ptolemy</a> and COSAC instruments on Philae <a href="http://www.bbc.co.uk/news/science-environment-30097648">found organic molecules</a>. When the Philae instruments report their data early next year we will be able to compare the D/H of water (as ice) with the ROSINA value for the D/H of water (as gas).</p>
<p>What will be interesting is to see what comes next – ROSINA continues to take spectra from 67P. As the comet approaches the Sun, its surface will become more active, and higher quantities of water will flow out into the coma. Will this water have the same D/H ratio? If not, what does that tell us about how a cometary surface evolves with time?</p>
<p>The Rosetta mission made a splash in the headlines with Philae’s nail-biting landing and the saga that played out over its battery life. Now with results on cometary water, a media splash is much more welcome to the mission scientists!</p><img src="https://counter.theconversation.com/content/35411/count.gif" alt="The Conversation" width="1" height="1" />
The first results on comet 67P Churyumov-Gerasimenko obtained by instruments on-board the Rosetta spacecraft have been announced – and they are, literally and figuratively, a deluge of information! Over…Monica Grady, Professor of Planetary and Space Sciences, The Open UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/341702014-12-05T18:10:45Z2014-12-05T18:10:45ZOrion: to boldly go, so long as the wind blows fair and the weather holds<figure><img src="https://images.theconversation.com/files/66440/original/image-20141205-8645-mredbs.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">The next generation of manned-space flight: Orion.</span> <span class="attribution"><span class="source">NASA</span></span></figcaption></figure><p>Generations of mariners have spent time anxiously watching the weather, waiting for the right conditions. It seems that despite all the high-tech advances we’ve made, spacecraft are still subject to the vagaries of the weather. </p>
<p>The <a href="http://www.nasa.gov/orion/">Orion</a> module, the vessel which will carry a new generation of astronauts beyond Earth orbit, had to remain Earth-bound for several days beyond its scheduled launch date because of high winds at Cape Canaveral. Fortunately, its <a href="http://www.bbc.co.uk/news/science-environment-30343171">launch went flawlessly</a>: the enormous spacecraft lifting-off dramatically into the Florida dawn. </p>
<p>Cameras on the outside of the fairing gave tremendous views of the curve of the Earth, and the thin line of the atmosphere as the rocket ascended. It travelled to an altitude of about 6,000km – to put this into perspective, the International Space Station orbits at about 430km, and the maximum Space Shuttle altitude was below 1,000km, while geostationary satellites orbit around 40,000km above the Earth’s surface. The Moon is 385,000km away. </p>
<p>Just over four hours later, having circled the Earth twice, the probe made an equally awesome re-entry into the atmosphere and <a href="http://www.bbc.co.uk/news/science-environment-30352472">splashdown</a> in the Pacific, parachutes billowing.</p>
<h2>Beyond Earth</h2>
<p>There is huge interest and investment in the success of the Orion venture. We have followed the activities of astronauts on the International Space Station with varying levels of engagement – for example, the Canadian astronaut, Commander Chris Hadfield, has notched up 24 million hits for his <a href="https://www.youtube.com/watch?v=KaOC9danxNo&list=UUtGG8ucQgEJPeUPhJZ4M4jA">rendition of David Bowie’s Space Oddity</a> during his flight on the ISS. But travel to the ISS is still a local neighbourhood activity. We are eager to escape the grip of Earth’s gravity and beyond, or at least to the Moon and then Mars. The Orion vessel is the next stage in the journey, following the trail of the Apollo astronauts back to the Moon, then, we anticipate, blazing a trail to Mars.</p>
<p>Before any of that can happen, though, Orion has to complete its test programme. The current mission, with no crew on-board, is designed to test re-entry capability. The outer part of the capsule will become incandescently hot – up to 2000°C as it decelerates from about 30,000km per hour on its flight through the atmosphere. Insulating the interior of the capsule from this heat is a crucial test of the module’s design. </p>
<h2>Beyond the solar system</h2>
<p>Assuming the flight is successful, what are the next stages in the programme? One of the technical reasons for the hiatus in human space exploration beyond Earth orbit has been the lack of a heavy lift vehicle. The Saturn V launcher used for Apollo was not re-commissioned, on the basis of cost. It has taken the intervening 40 years to develop the Delta IV rocket which launched Orion, and there will be at least another year before the Falcon Heavy (the launch vehicle designed and built by Space X for NASA) is ready for a test flight with Orion on board. </p>
<p>Human spaceflight beyond Earth orbit is expensive, and even NASA cannot now carry the costs alone. ESA is an important partner in the Orion project, as are private companies such as Space X, Boeing, etc. Decisions about mission priorities will have to be taken internationally, so once the crew-carrying module and its launch vehicle are on the launch pad – where will they go? To the Moon, to establish a lunar base? To Mars, to start human exploration of the Red Planet? There are still many obstacles to overcome: a new lunar rover and plans for in-situ resource utilisation for fuel on the Moon are probably the readiest to achieve. Neither NASA nor ESA believe that the appropriate technologies for human exploration of Mars will be in place much before 2030, especially given that no space agency yet has a craft capable of landing on Mars and taking off again.</p>
<p>Human spaceflight to Mars should not be seen as a one way opportunity – even though the Mars One, not for profit project, is planning to send four volunteers to establish a settlement on the planet by 2025. The project has attracted much international attention, although experts, including Chris Hadfield, <a href="http://www.newsweek.com/astronaut-chris-hadfield-questions-feasibility-mars-one-mission-289160">have spoken against the mission</a>, considering it to be underprepared. </p>
<p>The success of the Orion test flight, or more specifically, its return, is an encouraging step along the path to Mars. Although, of course, we have to make sure that the wind is blowing in the correct direction.</p><img src="https://counter.theconversation.com/content/34170/count.gif" alt="The Conversation" width="1" height="1" />
Generations of mariners have spent time anxiously watching the weather, waiting for the right conditions. It seems that despite all the high-tech advances we’ve made, spacecraft are still subject to the…Monica Grady, Professor of Planetary and Space Sciences, The Open UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/337632014-11-04T06:08:44Z2014-11-04T06:08:44ZWhy Rosetta is the greatest space mission of our lifetime<figure><img src="https://images.theconversation.com/files/63565/original/7vthqxts-1415033632.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">A giant leap for humans and robots.</span> <span class="attribution"><a class="source" href="http://www.esa.int/spaceinimages/Images/2014/09/Rosetta_and_Philae_at_comet">Huart, ESA</a></span></figcaption></figure><p>With only a week to go before the Rosetta spacecraft drops its Philae lander onto the surface of comet 67P, I wonder whether there will be another space mission in my lifetime that is so inspiring. Part of what has been so impressive is the length of time this mission has taken to finally get to the comet – 20 years since planning began (when I was still in high school), ten years since launch (when I was studying for my first degree). I feel very lucky that I am now employed as a space scientist at a time when all this work is coming to fruition.</p>
<p>Rosetta has now reached the bizarrely shaped rubber-duck comet and it has spent three months mapping its surface in the hope of finding a <a href="https://theconversation.com/historic-comet-landing-site-is-looking-for-a-name-33280">suitable spot</a> to place its Philae lander. This is a huge feat in itself. It is the first time a spacecraft has entered into orbit around a comet, which is a celestial body with almost no gravity. </p>
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<p>The <a href="http://www.esa.int/spaceinimages/Missions/Rosetta/%28class%29/image">images Rosetta has sent back</a> have allowed us to learn so much about this never-before-seen world. The European Space Agency (ESA) can already be proud of its achievements so far. </p>
<p>The Philae lander – packed with a science laboratory, harpoons and even ovens – gives the ESA a chance to do more. The hope is that Philae will help answer some of the most basic questions about our existence. </p>
<p>The original ambition for Rosetta was for it to be a sample-return mission: land on a comet and bring back samples to analyse on Earth. But the crippling costs of achieving this meant that it had to be scaled back: how about we just land on a speeding comet instead? </p>
<p>This strategy may cost less overall, but it wasn’t going to be much easier. On November 12, when Philae attempts to land, all manner of things can go wrong. The gravity of 67P is so small that Philae could hit the surface, bounce off and be lost in the emptiness of space. </p>
<p>We will nervously wait for news about Philae’s fate. After Philae leaves Rosetta, it will take about seven hours to reach the comet surface. If Rosetta achieves the comet landing, I believe it will be the most exciting space mission of my lifetime. (Of course, I wasn’t alive for the Apollo landings which will remain the most amazing space missions in history).</p>
<p>One could argue that there are many other missions in recent years that are just as impressive, if not more so, than Rosetta. It is usually the ones with the big backing from the US space agency NASA, such as the Curiosity rover mission that spring to mind. However, most recently I was impressed with the Indian mission, <a href="https://theconversation.com/billion-people-hold-their-breath-as-india-becomes-the-first-asian-country-to-reach-mars-32071">Mangalyaan</a>, that entered into Mars orbit this year after a ten-month journey – and with a tiny budget. </p>
<p>However, I have to admit, it sneaked up on me – I wasn’t really aware of Mangalyaan until a couple of days before the orbit was announced. This is where we find that a bit of quality promotion goes a long way. </p>
<p>Just take NASA’s Curiosity as an example, which continuously shares images of Mars’ surface. Even before it reached there, videos such as such as the famous <a href="http://mars.jpl.nasa.gov/msl/multimedia/videos/index.cfm?v=49">seven minutes of terror</a> captivated audiences. The mission itself is of course impressive. Mars is about 150 times farther from the Earth than the moon. And the crazy sky-crane landing, getting it down successfully I was sure it would end in failure. But it didn’t. The science continues to beamed back by the rover.</p>
<p>ESA has started to play catch-up with NASA and its most recent video release, called “<a href="http://www.esa.int/spaceinvideos/Videos/2014/10/Ambition_the_film">Ambition</a>”, really took me by surprise. It is definitely something out of the ordinary: a big-budget-style sci-fi movie, with famous actors, such as Aidan Gillen of Game of Thrones fame, and a subtle yet powerful message relating to the Rosetta mission.</p>
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<p>Whatever the movie cost to make, it was definitely worth it. We desperately need to inspire the space scientists of the future – and I spend a lot of time in schools chatting to children about their life ambitions in the hope they might want to follow me on a science career path. </p>
<p>My main words of advice to these children are similar to those that most stuck with me: aim high. I wanted to be an astronaut, so maybe I haven’t made it there (yet), but being a space scientist in such amazing times, when we are attempting to land on the surface of a comet, is not a bad second best.</p><img src="https://counter.theconversation.com/content/33763/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Natalie Starkey receives funding from the Science and Technology Facilities Council (STFC). </span></em></p>With only a week to go before the Rosetta spacecraft drops its Philae lander onto the surface of comet 67P, I wonder whether there will be another space mission in my lifetime that is so inspiring. Part…Natalie Starkey, Research Associate, The Open UniversityLicensed as Creative Commons – attribution, no derivatives.