tag:theconversation.com,2011:/fr/topics/zero-gravity-62651/articlesZero gravity – The Conversation2022-09-06T17:07:19Ztag:theconversation.com,2011:article/1893182022-09-06T17:07:19Z2022-09-06T17:07:19ZPregnancy in space: studying stem cells in zero gravity may determine whether it’s safe<figure><img src="https://images.theconversation.com/files/480786/original/file-20220824-12-m7s9pf.jpeg?ixlib=rb-1.1.0&rect=0%2C12%2C4243%2C3300&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Weightlessness affects how our cells develop and divide.</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/astronaut-works-orbit-above-earth-stars-180826439">MarcelClemens/Shutterstock</a></span></figcaption></figure><p>Space is a hostile, extreme environment. It’s only a matter of time before ordinary people are exposed to this environment, either by engaging in <a href="https://theconversation.com/virgin-galactic-space-tourism-takes-off-with-bransons-inaugural-flight-164142">space tourism</a> or by joining <a href="https://theconversation.com/heres-how-we-could-build-a-colony-on-an-alien-world-54923">self-sustaining colonies</a> far away from Earth. </p>
<p>To this end, there needs to be a much better understanding of how the environmental dangers of space will affect the biology of our cells, tissues, organs, and cognition. Crucially for future space colonies, we need to know whether we can easily reproduce in environments other than those found on Earth. </p>
<p>The effects of radiation on our cells, producing DNA damage, are <a href="https://www.nasa.gov/feature/space-radiation-is-risky-business-for-the-human-body">well documented</a>. What’s less clear is how lower levels of gravity, what scientists call <a href="https://www.nasa.gov/audience/forstudents/5-8/features/nasa-knows/what-is-microgravity-58.html">microgravity</a>, will affect the mechanisms and rhythms taking place within our cells. </p>
<p>Scientists are only just beginning to investigate how activity in our cells might be affected by exposure to microgravity. Crucially, experiments on embryonic stem cells, and models of <a href="https://www.sciencedirect.com/science/article/abs/pii/S0012160622000847">how embryos develop</a> in their first few weeks in space, will help us determine whether it’s possible for humans to produce offspring in the extraplanetary colonies of the future.</p>
<h2>Cosmic conception</h2>
<p>The ability to reproduce in space has been assessed in <a href="https://pubmed.ncbi.nlm.nih.gov/27220235/">a few animals</a>, including insects, amphibians, fish, reptiles, birds, and rodents. They have found that it’s certainly possible for organisms such as <a href="https://pubmed.ncbi.nlm.nih.gov/33572526/">fish, frogs and geckos</a> to produce fertilised eggs during spaceflight that can live and reproduce on Earth.</p>
<p>But the picture is more complicated in mammals. A study of mice, for instance, found that their <a href="https://www.britannica.com/animal/mammal/Reproduction#ref193721">oestrous cycle</a>, part of the reproductive cycle, was disrupted by <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7371565/?report=reader">exposure to microgravity</a>. Another study found that exposure to microgravity caused <a href="https://www.mdpi.com/2075-1729/11/2/109">negative neurological alterations</a> in rats. Hypothetically, these effects could also be transmitted to subsequent generations.</p>
<p>This likely happens because our cells did not evolve to work in microgravity. They evolved over millions of years on Earth, in it’s unique gravitational field. Earth’s gravity is part of what anchors and exerts physical force on our tissues, our cells, and our intracellular contents, helping to control specific movements within cells. The study of this is called <a href="https://www.mechanobio.info/">mechanobiology</a>. </p>
<figure class="align-center ">
<img alt="Inside a cell" src="https://images.theconversation.com/files/482248/original/file-20220901-19-612xxj.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/482248/original/file-20220901-19-612xxj.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=379&fit=crop&dpr=1 600w, https://images.theconversation.com/files/482248/original/file-20220901-19-612xxj.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=379&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/482248/original/file-20220901-19-612xxj.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=379&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/482248/original/file-20220901-19-612xxj.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=476&fit=crop&dpr=1 754w, https://images.theconversation.com/files/482248/original/file-20220901-19-612xxj.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=476&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/482248/original/file-20220901-19-612xxj.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=476&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Cells are busy with microbiological activity.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-illustration/components-eukaryotic-cell-nucleus-organelles-plasma-1649076208">Christoph Burgstedt/Shutterstock</a></span>
</figcaption>
</figure>
<p>The division of cells and the movement of genes and chromosomes within them, which is crucial to the development of a foetus, also works with and against the force of gravity as we know it on Earth. It follows that systems evolved to work perfectly in Earth’s gravity may be affected when the force of gravity changes.</p>
<h2>Foetal position</h2>
<p>When an embryo first starts to divide, in a process called <a href="https://www.britannica.com/science/cleavage-embryo">cleavage</a>, the rate of division can be faster at one end of the embryo than the other. Gravity plays a role here, determining the position of the very first building blocks in a human life. </p>
<p>Gravity also helps to establish the correct body plan of a foetus, ensuring the right cells develop in the right places in the right numbers and in the right spatial orientation.</p>
<p>Researchers have investigated whether embryonic stem cells, which are “<a href="https://www.sciencedirect.com/topics/immunology-and-microbiology/pluripotent-stem-cell">pluripotent</a>” and can develop into all cells of the body, are affected by microgravity. At present, there is <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6528932/">some evidence</a> that when rodent embryonic stem cells are subjected to microgravity, their ability to become the desired cell types may be impacted.</p>
<p>It is also possible to produce pluripotent human stem cells from normal mature cells of our bodies, which are called <a href="https://www.britannica.com/science/induced-pluripotent-stem-cell">induced pluripotent stem cells</a>. These have also been studied under microgravity, with experiments on Earth finding that induced stem cells <a href="https://www.nature.com/articles/srep30956">proliferate faster</a> in simulated microgravity. Two batches of these stem cells are currently on the <a href="https://www.smithsonianmag.com/smart-news/scientists-just-sent-two-batches-of-stem-cells-into-space-180980441/">International Space Station</a> to see whether these results can be replicated in space.</p>
<figure class="align-center ">
<img alt="The International Space Station" src="https://images.theconversation.com/files/482249/original/file-20220901-16-oi4w5z.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/482249/original/file-20220901-16-oi4w5z.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=375&fit=crop&dpr=1 600w, https://images.theconversation.com/files/482249/original/file-20220901-16-oi4w5z.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=375&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/482249/original/file-20220901-16-oi4w5z.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=375&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/482249/original/file-20220901-16-oi4w5z.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=471&fit=crop&dpr=1 754w, https://images.theconversation.com/files/482249/original/file-20220901-16-oi4w5z.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=471&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/482249/original/file-20220901-16-oi4w5z.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=471&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">The International Space Station regularly plays host to scientific experiments.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/international-space-station-over-planet-earth-551379514">Vadim Sadovski/Shutterstock</a></span>
</figcaption>
</figure>
<p>If adult stem cells do proliferate faster in space, it could open the door for commercial <a href="https://www.cedars-sinai.org/newsroom/cedars-sinai-looks-to-space-for-tomorrows-stem-cell-therapies/">stem cell manufacturers</a> to produce these cells in orbit, seeing as it’s difficult to culture enough stem cells on Earth to treat degenerative diseases with <a href="https://www.sciencedirect.com/topics/medicine-and-dentistry/stem-cell-therapy">stem cell therapies</a>.</p>
<h2>Gravitational field</h2>
<p>Besides normal cellular processes, it’s also unclear how fertilisation, hormone production, lactation, and even birth itself will be affected by exposure to microgravity. </p>
<p>It seems that short-term exposure to microgravity, of perhaps half an hour, will probably not have too much of an effect on our cells. But longer exposures of days or weeks are likely to have an effect. This is not taking into account the effect of radiation on our cells and DNA, but we already know how to protect against radiation.</p>
<p>Scientists are looking at two ways to protect against the adverse effects of microgravity on our biology: intervention at the cellular level, using drugs or nanotechnology, and intervention on the environmental level, by simulating Earth’s gravity in spacecraft or off-world colonies. Both fields of study are in their early stages.</p>
<p>Still, studying stem cells in space provides a valuable window into how pregnancy could work, or not work, when we’re outside Earth’s gravitational field. For now, those fortunate enough to go to space might do well to avoid attempting to conceive before, during or directly after a space flight.</p><img src="https://counter.theconversation.com/content/189318/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>The authors do not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and have disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Avoid while pregnant or trying to conceive: smoking, drinking, space travel.Joanna Bridger, Director of the Centre for Genome Engineering and Maintenance (CenGEM), Professor of Genome Organisation, Brunel University LondonEmmanouil Karteris, Reader in Biomedical Sciences, Brunel University LondonLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1856012022-06-23T02:55:08Z2022-06-23T02:55:08ZAustralia just flew its own ‘vomit comet’. It’s a big deal for zero-gravity space research<figure><img src="https://images.theconversation.com/files/470423/original/file-20220623-52178-3o78bp.jpg?ixlib=rb-1.1.0&rect=9%2C14%2C1590%2C1183&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Steve Gale (pilot) and Gail Iles (right) next to the Marchetti jet.</span> <span class="attribution"><span class="source">Kieran Blair</span>, <span class="license">Author provided</span></span></figcaption></figure><p>Last Saturday, a two-seater SIAI-Marchetti S.211 jet took off from Essendon Fields Airport in Melbourne with an expert aerobatic pilot at the controls and a case full of scientific experiments in the passenger seat. </p>
<p>Pilot <a href="https://www.anyfoolcanfly.com/">Steve Gale</a> took the jet on Australia’s first commercial “parabolic flight”, in which the plane flies along the path of a freely falling object, creating a short period of weightlessness for everyone and everything inside.</p>
<p>Parabolic flights are often a test run for the zero-gravity conditions of space. This one was operated by Australian space company <a href="https://beingssystems.com">Beings Systems</a>, which plans to run regular commercial flights in coming years. </p>
<p>As Australia’s space program begins to take off, flights like these will be in high demand.</p>
<h2>What was on the plane?</h2>
<p>The experiments aboard the flight were small packages developed by space science students at RMIT University. As program manager of RMIT’s space science degree, I have been teaching these students for the past three years, preparing them for a career in the Australian space industry. </p>
<p>The experiments investigate the effect of zero gravity on plant growth, crystal growth, heat transfer, particle agglomeration, foams and magnetism.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/470227/original/file-20220622-26999-hzbn34.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/470227/original/file-20220622-26999-hzbn34.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/470227/original/file-20220622-26999-hzbn34.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=338&fit=crop&dpr=1 600w, https://images.theconversation.com/files/470227/original/file-20220622-26999-hzbn34.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=338&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/470227/original/file-20220622-26999-hzbn34.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=338&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/470227/original/file-20220622-26999-hzbn34.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=424&fit=crop&dpr=1 754w, https://images.theconversation.com/files/470227/original/file-20220622-26999-hzbn34.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=424&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/470227/original/file-20220622-26999-hzbn34.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">RMIT University science payloads designed for parabolic flight.</span>
<span class="attribution"><span class="source">Gail Iles</span></span>
</figcaption>
</figure>
<p>Scientific phenomena behave differently in zero gravity than in labs on Earth. This is important for two main reasons. </p>
<p>First, zero gravity, or “microgravity”, provides a very “clean” environment in which to conduct experiments. By removing gravity from the system, we can study a phenomenon in a more “pure” state and thus understand it better. </p>
<p>Second, microgravity platforms such as parabolic flights, sounding rockets and drop towers provide test facilities for equipment and science before it is sent into space.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/to-carve-out-a-niche-in-space-industries-australia-should-focus-on-microgravity-research-rockets-119225">To carve out a niche in space industries, Australia should focus on microgravity research rockets</a>
</strong>
</em>
</p>
<hr>
<h2>Lab on a plane: a mini ISS</h2>
<p>Last Saturday’s flight was a success, with the six experiments recording a variety of data and images. </p>
<p>The plants experiment observed broccoli seedlings throughout the flight and found no adverse reactions to hyper- or micro-gravity. </p>
<p>Another experiment formed a crystal of sodium acetate trihydrate in microgravity, which grew much larger than its counterpart on the ground. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/470282/original/file-20220622-24-u5clgq.gif?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/470282/original/file-20220622-24-u5clgq.gif?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/470282/original/file-20220622-24-u5clgq.gif?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=205&fit=crop&dpr=1 600w, https://images.theconversation.com/files/470282/original/file-20220622-24-u5clgq.gif?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=205&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/470282/original/file-20220622-24-u5clgq.gif?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=205&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/470282/original/file-20220622-24-u5clgq.gif?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=258&fit=crop&dpr=1 754w, https://images.theconversation.com/files/470282/original/file-20220622-24-u5clgq.gif?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=258&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/470282/original/file-20220622-24-u5clgq.gif?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=258&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Insulin crystals grown in standard gravity (left) are smaller than those grown in microgravity (right).</span>
<span class="attribution"><span class="source">NASA</span></span>
</figcaption>
</figure>
<p>The biggest zero-gravity lab is of course the International Space Station (ISS), where studies of plant growth, crystal growth and physical science phenomena are commonplace. At any one time 300 experiments are taking place on the ISS. </p>
<p>Turning a benchtop experiment into a self-contained science payload for space is not easy. Each one must be rigorously tested before launch to make sure it will work once it gets there, using parabolic flights or other testing platforms.</p>
<h2>Going ‘zero-g’</h2>
<p>There’s a common misconception that you have to go into space to experience microgravity. In fact, it’s the condition of freefall that makes things apparently weightless and that can be experienced here on Earth too. </p>
<p>If you throw a ball to a friend, it traces an arc as it flies through the air. From the moment it leaves your hand it’s in freefall – yes, even on the way up – and this is the exact same arc that the aircraft flies. Instead of a hand, it has an engine providing the “push” it needs to travel and fall through the air, tracing out a parabolic arc as it goes.</p>
<figure class="align-center ">
<img alt="Diagram showing the speed, acceleration and direction of flight of an aeroplane in parabolic flight." src="https://images.theconversation.com/files/470252/original/file-20220622-22-habw01.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/470252/original/file-20220622-22-habw01.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=273&fit=crop&dpr=1 600w, https://images.theconversation.com/files/470252/original/file-20220622-22-habw01.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=273&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/470252/original/file-20220622-22-habw01.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=273&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/470252/original/file-20220622-22-habw01.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=343&fit=crop&dpr=1 754w, https://images.theconversation.com/files/470252/original/file-20220622-22-habw01.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=343&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/470252/original/file-20220622-22-habw01.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=343&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">The flight trajectory during the parabolic manoeuvre.</span>
<span class="attribution"><a class="source" href="https://www.nature.com/articles/s41598-017-03170-5">Van Ombergen et al., Scientific Reports (2017)</a></span>
</figcaption>
</figure>
<p>Even the International Space Station is experiencing the very same freefall as the ball or the aircraft. The only difference for the ISS is it has enough velocity to “miss the ground” and keep going forwards. The combination of the forward velocity and the pull towards Earth keep it going around in circles, orbiting the planet.</p>
<h2>Human spaceflight</h2>
<p>Parabolic flights in the USA and Europe occur every two or three months. On the flights, researchers conduct science, companies test technologies and astronauts receive training in preparation for spaceflight missions. </p>
<p><div data-react-class="Tweet" data-react-props="{"tweetId":"1537970435538976768"}"></div></p>
<p>As a researcher at the European Space Agency and former <a href="https://www.theguardian.com/careers/careers-blog/changing-direction-becoming-an-astronaut-instructor">astronaut instructor</a>, I am a veteran of five parabolic flight campaigns in Europe. I’ve completed over 500 parabolas on board the Novespace Airbus A300. </p>
<p>While I have <a href="https://www.youtube.com/watch?v=xyZYP0jUyBU">never become sick on these flights</a>, up to 25% of people aboard do vomit in the zero-g conditions. This is why they are sometimes called “vomit comets”.</p>
<h2>Why now?</h2>
<p>So why does Australia need parabolic flights all of a sudden? Since the Australian Space Agency was established in 2018, several space projects have received funding, including a <a href="https://www.industry.gov.au/news/gday-moon-australias-boldest-adventure-yet">lunar rover</a>, <a href="https://www.spaceconnectonline.com.au/industry/5371-budget-australia-will-build-and-operate-four-new-satellites">four Earth-observation satellites</a> and a <a href="https://www.rmit.edu.au/news/all-news/2020/jun/locally-designed-space-suits">space suit</a>. </p>
<p>For these projects to succeed, all their various systems and components will need to be tested. That’s where parabolic flights come in. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/470398/original/file-20220622-39985-9leckq.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/470398/original/file-20220622-39985-9leckq.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/470398/original/file-20220622-39985-9leckq.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=344&fit=crop&dpr=1 600w, https://images.theconversation.com/files/470398/original/file-20220622-39985-9leckq.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=344&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/470398/original/file-20220622-39985-9leckq.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=344&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/470398/original/file-20220622-39985-9leckq.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=432&fit=crop&dpr=1 754w, https://images.theconversation.com/files/470398/original/file-20220622-39985-9leckq.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=432&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/470398/original/file-20220622-39985-9leckq.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=432&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 plane flying over Melbourne (top left), with students (bottom left) and readying for flight (right).</span>
<span class="attribution"><span class="source">Beings Systems</span></span>
</figcaption>
</figure>
<p>As the demand increases, so too will the Australian aircraft. Beings Systems has plans to offer a larger aircraft –- such as a Lear jet – by 2023, such that researchers and companies alike can test their equipment, large and small, without leaving the country.</p>
<p>In addition to reading exciting scientific papers on the latest phenomena observed in microgravity, we’ll begin to see footage of satellites testing deployment of their antennae and people donning and doffing spacesuits on board parabolic flights.</p><img src="https://counter.theconversation.com/content/185601/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>A freefalling ‘parabolic flight’ launched from Essendon airport is a leap for home-grown space science in Australia.Gail Iles, Senior Lecturer in Physics, RMIT UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1533702021-03-15T12:56:33Z2021-03-15T12:56:33ZHow do astronauts go to the bathroom in space?<figure><img src="https://images.theconversation.com/files/386501/original/file-20210225-23-146zub9.jpg?ixlib=rb-1.1.0&rect=71%2C170%2C5919%2C3817&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Toilets in space are a bit more complicated than those on Earth. </span> <span class="attribution"><a class="source" href="https://en.wikipedia.org/wiki/Space_toilet#/media/File:Space_Toilet_(8687080967).jpg">Don DeBold via Wikipedia</a>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span></figcaption></figure><figure class="align-left ">
<img alt="" src="https://images.theconversation.com/files/281719/original/file-20190628-76743-26slbc.png?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/281719/original/file-20190628-76743-26slbc.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=293&fit=crop&dpr=1 600w, https://images.theconversation.com/files/281719/original/file-20190628-76743-26slbc.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=293&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/281719/original/file-20190628-76743-26slbc.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=293&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/281719/original/file-20190628-76743-26slbc.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=368&fit=crop&dpr=1 754w, https://images.theconversation.com/files/281719/original/file-20190628-76743-26slbc.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=368&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/281719/original/file-20190628-76743-26slbc.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=368&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption"></span>
</figcaption>
</figure>
<p><em><a href="https://theconversation.com/us/topics/curious-kids-us-74795">Curious Kids</a> is a series for children of all ages. If you have a question you’d like an expert to answer, send it to <a href="mailto:curiouskidsus@theconversation.com">CuriousKidsUS@theconversation.com</a>.</em></p>
<hr>
<blockquote>
<p><strong>How do astronauts go to the bathroom in space? – Henry D., age 7, Cambridge, Massachusetts</strong></p>
</blockquote>
<hr>
<p>Whether you use a hole in the ground or a fancy gold-plated toilet, on Earth, gravity pulls your waste down and away from you. For astronauts, “doing their duty” is a bit more complicated. Without gravity, any loose drops or dribbles could float out of the toilet. That’s not good for astronauts’ health, nor for the sensitive equipment inside the space station. </p>
<p>I <a href="http://www.buffalo.edu/news/experts/tracy-gregg-faculty-expert-planetary-volcanology.html">study volcanoes on other planets</a>, and I’m interested in how people can work in extreme environments like space. </p>
<p>So how do you go to the bathroom in space or on the International Space Station? Carefully – and with suction.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/387394/original/file-20210303-23-o6iwpi.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="The new NASA Universal Waste Management System has a steel lid, controls and many tubes surrounding the toilet bowl." src="https://images.theconversation.com/files/387394/original/file-20210303-23-o6iwpi.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/387394/original/file-20210303-23-o6iwpi.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=900&fit=crop&dpr=1 600w, https://images.theconversation.com/files/387394/original/file-20210303-23-o6iwpi.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=900&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/387394/original/file-20210303-23-o6iwpi.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=900&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/387394/original/file-20210303-23-o6iwpi.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1131&fit=crop&dpr=1 754w, https://images.theconversation.com/files/387394/original/file-20210303-23-o6iwpi.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1131&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/387394/original/file-20210303-23-o6iwpi.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1131&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 new toilet is more comfortable, easier to use for both men and women, and lighter.</span>
<span class="attribution"><a class="source" href="https://commons.wikimedia.org/wiki/File:ISS_Universal_Waste_Management_System_(3).jpg#/media/File:ISS_Universal_Waste_Management_System_(3).jpg">NASA/James Blair via Wikimedia Commons</a></span>
</figcaption>
</figure>
<h2>A bathroom vacuum</h2>
<p>In 1961, Alan Shepard became the first American in space. His trip was supposed to be short, so there was <a href="https://doi.org/10.1152/advan.00175.2012">no plan for pee</a>. But the launch was delayed for over three hours after Shepard climbed into the rocket. Eventually, he asked if he could exit the rocket to pee. Instead of wasting more time, mission control concluded that Shepard could safely pee inside his spacesuit. The first American in space went up in <a href="https://www.realclearscience.com/blog/2013/06/the-science-and-history-of-space-urination.html">damp underwear</a>.</p>
<p>Fortunately, there’s a toilet on the space station these days. The original toilet was designed in 2000 for men and was difficult for women to use: You had to pee while standing up. To poop, astronauts used thigh straps to sit on the small toilet and to keep a tight seal between their bottoms and the toilet seat. It didn’t work very well and was hard to keep clean. </p>
<p>So in 2018, NASA spent US$23 million on a <a href="https://ntrs.nasa.gov/api/citations/20130011635/downloads/20130011635.pdf">new and improved toilet</a> for astronauts on the International Space Station. To get around the problems of zero-gravity bathroom breaks, the <a href="https://www.youtube.com/watch?v=C-65mBQ7s_Q">new toilet</a> is a specially designed <a href="https://www.nasa.gov/feature/boldly-go-nasa-s-new-space-toilet-offers-more-comfort-improved-efficiency-for-deep-space">vacuum toilet</a>. There are two parts: a hose with a funnel at the end for peeing and a small raised toilet seat for pooping.</p>
<p>The bathroom is full of handholds and footholds so that astronauts don’t drift off in the middle of their business. To pee, they can sit or stand and then hold the funnel and hose tightly against their skin so that nothing leaks out. To poop, astronauts lift the toilet lid and sit on the seat – just like here on Earth. But this toilet starts suctioning as soon as the lid is lifted to prevent things from drifting away – and to control the stink. To make sure that there is a tight fit between the toilet seat and the astronauts’ behinds, the toilet seat is smaller than the one in your house. </p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/387396/original/file-20210303-15-d8nb37.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="The Russian Progress spacecraft floating above Earth. It is cylindrical with two solar panels sticking out to the sides." src="https://images.theconversation.com/files/387396/original/file-20210303-15-d8nb37.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/387396/original/file-20210303-15-d8nb37.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=429&fit=crop&dpr=1 600w, https://images.theconversation.com/files/387396/original/file-20210303-15-d8nb37.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=429&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/387396/original/file-20210303-15-d8nb37.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=429&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/387396/original/file-20210303-15-d8nb37.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=539&fit=crop&dpr=1 754w, https://images.theconversation.com/files/387396/original/file-20210303-15-d8nb37.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=539&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/387396/original/file-20210303-15-d8nb37.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=539&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Russian Progress spacecrafts bring supplies to the ISS and take on trash and waste, which is then burned up in the atmosphere with the spacecraft.</span>
<span class="attribution"><a class="source" href="https://en.wikipedia.org/wiki/Progress_(spacecraft)#/media/File:Progress_M-52.jpg">NASA/Wikimedia Commons</a></span>
</figcaption>
</figure>
<h2>After the deed is done</h2>
<p>Pee is more than 90% water. Since water is heavy and takes up a lot of space, it is better to recycle pee rather than bring up clean water from Earth. All astronaut pee is collected and turned back into clean, drinkable water. Astronauts say that “Today’s coffee is <a href="https://www.facebook.com/jsceducation/posts/1823486837754155">tomorrow’s coffee!</a>”</p>
<p>Sometimes, astronaut poop is brought <a href="https://www.pbs.org/newshour/science/how-scott-kellys-year-in-space-changed-his-poop">back to Earth</a> for scientists to study, but most of the time, bathroom waste – including poop – is burned. Poop is vacuumed into garbage bags which are put into airtight containers. Astronauts also put toilet paper, wipes and gloves – gloves help keep everything clean – in the containers too. The containers are then loaded into a cargo ship that brought supplies to the space station, and this ship is launched at Earth and <a href="https://www.nasa.gov/mission_pages/station/research/news/infographic_yearinspace">burns up</a> in Earth’s upper atmosphere. </p>
<p>If you’ve ever seen a shooting star, it might have been a meteorite burning up in Earth’s atmosphere – or it might have been flaming astronaut poo. And the next time you have to pee or poop, be thankful that you’re doing it with gravity’s help.</p>
<hr>
<p><em>Hello, curious kids! Do you have a question you’d like an expert to answer? Ask an adult to send your question to <a href="mailto:curiouskidsus@theconversation.com">CuriousKidsUS@theconversation.com</a>. Please tell us your name, age and the city where you live.</em></p>
<p><em>And since curiosity has no age limit – adults, let us know what you’re wondering, too. We won’t be able to answer every question, but we will do our best.</em></p><img src="https://counter.theconversation.com/content/153370/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Tracy K.P. Gregg 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>Going to the bathroom is much more complicated in space without any gravity. To solve this problem of tricky orbital potty breaks, NASA builds special toilets that work without gravity.Tracy K.P. Gregg, Associate Professor of Geology, University at BuffaloLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1331442020-06-18T12:17:10Z2020-06-18T12:17:10ZWhat is the ‘zero gravity’ that people experience in the vomit comet or space flight?<figure><img src="https://images.theconversation.com/files/325378/original/file-20200403-74225-11htk9q.JPG?ixlib=rb-1.1.0&rect=13%2C0%2C4587%2C2586&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">People in a special airplane flight get to float like there is no gravity – just like astronauts</span> <span class="attribution"><span class="source">Steven Collicott</span></span></figcaption></figure><figure class="align-left ">
<img alt="" src="https://images.theconversation.com/files/281719/original/file-20190628-76743-26slbc.png?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/281719/original/file-20190628-76743-26slbc.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=293&fit=crop&dpr=1 600w, https://images.theconversation.com/files/281719/original/file-20190628-76743-26slbc.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=293&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/281719/original/file-20190628-76743-26slbc.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=293&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/281719/original/file-20190628-76743-26slbc.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=368&fit=crop&dpr=1 754w, https://images.theconversation.com/files/281719/original/file-20190628-76743-26slbc.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=368&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/281719/original/file-20190628-76743-26slbc.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=368&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption"></span>
</figcaption>
</figure>
<p><em><a href="https://theconversation.com/us/topics/curious-kids-us-74795">Curious Kids</a> is a series for children of all ages. If you have a question you’d like an expert to answer, send it to <a href="mailto:curiouskidsus@theconversation.com">curiouskidsus@theconversation.com</a>.</em></p>
<hr>
<blockquote>
<p><strong>In the zero-gravity airplanes or vomit comet, why does stuff behave like there is no gravity when it is just falling? – Austin B., 11, Scranton, Pennsylvania</strong></p>
</blockquote>
<hr>
<p>I have flown many times in zero-gravity airplane flights. Each time I still enjoy the feeling of floating free, the ability to fly across the cabin from just one gentle push on the wall, just like astronauts in the International Space Station, and the novelty of rotating your body in whatever direction you choose. The feeling is like the brief sensation on some roller coasters or off of a diving board, but for close to half a minute and without the air rushing past you – it’s fun!</p>
<p>People feeling weightlessness without being in spaceflight might seem like a contradiction. But it is possible, and people frequently choose to do this for recreation or for research in an airplane that is flying in the atmosphere, not out in space. </p>
<p><a href="https://engineering.purdue.edu/AAE/people/ptProfile?resource_id=1370">I am a researcher in aerospace engineering</a> and am interested in how to control and use liquids and gases in spaceflight. Examples are liquid rocket propellants in spacecraft or water in life support systems in human spacecraft. </p>
<h2>Examples of gravity in action</h2>
<p>When standing still, you actually experience the force we call gravity when you feel the Earth pull us toward its center. Gravity pulls you down, and the floor pushes up on your feet. If gravity disappeared, you could push off of the floor and float away, never returning to the floor unless you found a ceiling to push off of again. You would appear to float around like someone in a “<a href="https://www.space.com/37942-vomit-comet.html">vomit-comet</a>” airplane flight or an astronaut in the International Space Station. </p>
<p>You may have learned that the space station orbits the Earth because the force of gravity on it is balanced by the sideways force caused by the circular flight path. This force is called centrifugal force, the same that you feel when turning in a car, train, amusement park ride or similar. </p>
<p>Airplanes fly closer to Earth’s surface, so gravity is a little stronger for the airplane than the International Space Station. But clearly the force of gravity caused by the Earth exists at the space station and at the vomit-comet, yet astronauts in space station and researchers or tourists in the vomit-comet look like there is no gravity. Why?</p>
<p>I have flown in the vomit-comet flights with science experiments and Purdue University students, and indeed, the experience feels like there is no gravity. </p>
<p>Yet each time I fly, gravity pulls the airplane down to the ground for the landing on the runway. Therefore, we know gravity must be present, and yet people look like and feel like there is no gravity during part of the vomit-comet flight. </p>
<p>These research flights are typically full of qualified researchers who have earned an advanced degree, in my case a Ph.D. </p>
<h2>How weightlessness in an airplane happens</h2>
<p>One everyday event might help you understand how apparently gravity is both present and absent at the same time. When you ride in a car that turns to the left, you feel pushed to right. You may even feel pushed against the right-hand side of the car’s interior, and the door pushes back on you. Turning in the direction the car is traveling also changes what we call the velocity of the car. </p>
<p>Velocity encompasses both the speed of the car and the direction that it is traveling. Changing the direction feels like sideways gravity to you. Changing the speed, such as a sudden stop, feels like forwards gravity to you. Elevators starting and stopping feel for a moment like there is more or less gravity. These changes in velocity are called accelerations. Acceleration has an amount and direction, just like velocity does, and both are examples of vectors. Another vector is force, and one example is gravity, which pulls us down to the Earth’s surface.</p>
<p>You have experienced that acceleration feels the same as gravity does. Suppose you could find a way to create an “anti-gravity” acceleration: that is, an acceleration acting in the right direction and in the right amount to cancel out gravity. Is this possible? </p>
<p>The answer is yes – this is what happens in a vomit-comet flight and in an orbit.</p>
<p>The shape of the vomit-comet flight path is called a parabola. Pilots achieve this by flying upwards at an angle of about 45 degrees and then they level out and dive at about 45 degrees, which creates the acceleration needed to cancel out gravity. The maximum speed for the airplane and how rapidly the airplane can pull up before and after a parabola determine how long this acceleration can last, about 25 seconds. </p>
<p>Gravity pulls down on us, and by accelerating down in just the right way in an aircraft or spacecraft, we can feel like we are in zero gravity. The correct physical term is weightlessness, but zero gravity is a descriptive term that also describes the sensation, so even in the aerospace research world and in NASA, “zero gravity” is the common term used most often by experts. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/331468/original/file-20200429-51466-1th4zk2.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/331468/original/file-20200429-51466-1th4zk2.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/331468/original/file-20200429-51466-1th4zk2.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=408&fit=crop&dpr=1 600w, https://images.theconversation.com/files/331468/original/file-20200429-51466-1th4zk2.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=408&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/331468/original/file-20200429-51466-1th4zk2.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=408&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/331468/original/file-20200429-51466-1th4zk2.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=513&fit=crop&dpr=1 754w, https://images.theconversation.com/files/331468/original/file-20200429-51466-1th4zk2.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=513&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/331468/original/file-20200429-51466-1th4zk2.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=513&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Flight trajectory for a typical zero-gravity flight maneuver.</span>
<span class="attribution"><a class="source" href="https://upload.wikimedia.org/wikipedia/commons/2/2f/Zero_gravity_flight_trajectory_C9-565.jpg">C-9B Flight Trajectory, NASA Reduced Gravity Research Program</a></span>
</figcaption>
</figure>
<hr>
<p><em>Hello, curious kids! Do you have a question you’d like an expert to answer? Ask an adult to send your question to <a href="mailto:curiouskidsus@theconversation.com">CuriousKidsUS@theconversation.com</a>. Please tell us your name, age and the city where you live.</em></p>
<p><em>And since curiosity has no age limit – adults, let us know what you’re wondering, too. We won’t be able to answer every question, but we will do our best.</em></p><img src="https://counter.theconversation.com/content/133144/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Steven Collicott receives funding from NASA. He is affiliated with the Sub-orbital Applications Researchers Group Commercial Spaceflight Federation and CASIS/ISS-National Lab. </span></em></p>How do people in a special airplane flight get to float like there is no gravity – just like astronauts? An aerospace engineer explains.Steven Collicott, Professor of Aeronautics and Astronautics, Purdue UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1223592019-09-16T11:01:01Z2019-09-16T11:01:01ZWhat neuroscientists are learning about our brains in space by launching themselves into zero gravity flight<figure><img src="https://images.theconversation.com/files/290333/original/file-20190830-165977-764tbq.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><span class="source">Image courtesy of author</span></span></figcaption></figure><p>More than 500 people <a href="https://www.worldspaceflight.com/bios/stats.php">have travelled into space</a> to date and, while we know a little about how life without gravity <a href="https://theconversation.com/five-things-that-happen-to-your-body-in-space-52940">affects our physical health</a>, we know almost nothing about how it affects our minds.</p>
<p>So, my colleagues and I have been launching ourselves, rigs of equipment and our participants into “zero gravity flight” to perform experiments. It’s a thrilling – and sometimes extremely nauseating – life, but its opening new windows into how we think and perceive differently in space. This is no doubt important if we want to colonise outer space.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/290335/original/file-20190830-165981-1mzpujm.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/290335/original/file-20190830-165981-1mzpujm.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/290335/original/file-20190830-165981-1mzpujm.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/290335/original/file-20190830-165981-1mzpujm.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/290335/original/file-20190830-165981-1mzpujm.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/290335/original/file-20190830-165981-1mzpujm.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/290335/original/file-20190830-165981-1mzpujm.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">Living without gravity can be more than disconcerting – it can affect our health and the way our brains work.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/download/confirm/634542614?src=-1-30&size=huge_jpg">Rick Partington/ Shutterstock</a></span>
</figcaption>
</figure>
<p>Weightlessness is a key component of the spaceflight experience. Since the first space missions, however, it’s been clear weightlessness causes <a href="https://theconversation.com/what-happens-to-the-brain-in-zero-gravity-106256">a variety of health issues</a> – particularly <a href="https://www.nature.com/articles/nrcardio.2017.157">degrading muscle mass</a>, causing <a href="https://www.nature.com/articles/npjmgrav201631">disorientation and blurred vision</a>.</p>
<p>This should not be surprising as all living organisms have evolved under the constant “1g” of gravitational force. But we also need to find out how weightlessness influences our perception and behaviour. Without going to the International Space Station (ISS), the best way to do this is on a <a href="https://www.airzerog.com">zero gravity flight</a>. During these flights, a refitted Airbus A310 aircraft follows the trajectory of a parabola. This means it alternates between rises and descents, at a 45° angle of inclination.</p>
<p>Each parabola starts with a “pull-up” acceleration phase in which the gravitational load is double Earth gravity (hypergravity, 2g). This lasts about 20 seconds. The pilots then let the aircraft drop into “free-fall”. For the next 20 seconds, everything and everybody on board the aircraft is exposed to weightlessness (<a href="https://theconversation.com/explainer-what-is-microgravity-57898">microgravity</a>, 0g). Once the craft reaches a particular angle of tilt, the pilots perform a “pull-out” acceleration, in which gravity is again double. This is repeated up to 30 times and the entire flight lasts around three hours.</p>
<h2>Bumpy ride</h2>
<p>Doing science on these roller coaster parabolic flight manoeuvres is very challenging. There are severe constraints on time. Whatever the experiment requires, it has to be performed in about 20 seconds.</p>
<p>Because several experiments must go up together, space is also tight. So, forget the comfort of a lab. Instead, visualise a 1.5 x 1.5 metres allocated habitat – in which your equipment, experimenters and participants all need to fit. You can’t risk mistakes so each experimental step, even each movement, needs to be perfectly planned. These movements must also be perfectly synchronised with drops and lifts of the plane. Like a dance, we choreograph and rehearse in the days before lift off. </p>
<p>To me, the real challenge of doing science on a parabolic flight is dealing with motion sickness. It is not by chance that parabolic flights have earned the nickname “Vomit Comet”.</p>
<p>On Earth, we have a system in our inner ear that tells us the direction and amount of gravitational pull, relative to the position of our heads (<a href="http://www.columbia.edu/itc/hs/medical/neuralsci/2004/slides/32_LectureSlides.pdf">the vestibular system</a>). In weighlessness, the 1g pull we have experienced our whole lives disappears. The vestibular system can no longer function as it should, often leading to space motion sickness (which mimics a severe car motion sickness), nausea and vomiting.</p>
<h2>The science</h2>
<p>Why embark on such an adventure? This is the ultimate frontier of understanding how the brain can adapt to new environments and demands in microgravity. On a practical level, understanding the brain’s response to weightlessness is necessary to ensure the success and safety of future manned space missions.</p>
<p>We have also been investigating the effect of gravity on the perception of our own body weight. So far research has looked largely at how society and culture affects body weight perception. And <a href="https://www.sciencedirect.com/science/article/abs/pii/S1740144515300085">we know that</a> body satisfaction, body image and risk for eating disorders play a role.</p>
<p>However, the true weight of our body – like any other object on Earth – depends on the pull of gravity. Because of this, we predicted the way we <em>perceive</em> our own body weight would also be dependent on the pull of gravity. We asked participants to estimate the weight of their hand and their head both in normal terrestrial gravity and during exposure to microgravity and hypergravity on a European Space Agency parabolic flight campaign at the German Aerospace Center (DLR Cologne). </p>
<p>We showed that alterations of gravity <a href="https://www.nature.com/articles/s41598-019-47663-x">produced rapid changes</a> in perceived weight: there was an increase in perceived weight during hypergravity, and a decrease during microgravity. </p>
<p>While this might seem obvious – our actual weight changes accordingly – it’s important, because perceptions of our body weight, shape and position are critical to successful movement and interactions with our surroundings. The fact that we are researching such basic things just goes to show how little we actually know about it. Imagine, for example, that you are an astronaut operating levers to control a <a href="https://www.nasa.gov/mission_pages/station/research/news/b4h-3rd/hh-robotic-arms-reach">robotic space arm</a>. Misunderstanding the weight of your own arm could cause you to pull too hard, swinging the arm into the side of your spacecraft. </p>
<p>Ultimately, we aim to understand how the human brain builds a representation of gravity and uses it in cognition to guide behaviour. We have previously shown that gravity may influence how we make decisions, with a lack of it potentially <a href="https://theconversation.com/gravity-influences-how-we-make-decisions-new-research-111935">making us more risk-averse</a>. This sort of research has never been more timely and it yields advantages for enhancing human performance in upcoming space exploration.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/290334/original/file-20190830-165985-1kq11wl.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/290334/original/file-20190830-165985-1kq11wl.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=800&fit=crop&dpr=1 600w, https://images.theconversation.com/files/290334/original/file-20190830-165985-1kq11wl.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=800&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/290334/original/file-20190830-165985-1kq11wl.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=800&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/290334/original/file-20190830-165985-1kq11wl.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1005&fit=crop&dpr=1 754w, https://images.theconversation.com/files/290334/original/file-20190830-165985-1kq11wl.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1005&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/290334/original/file-20190830-165985-1kq11wl.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">
<figcaption>
<span class="caption">Me in my flight suit on a recent trip into the atmosphere.</span>
<span class="attribution"><span class="source">Courtesy of author</span></span>
</figcaption>
</figure>
<p>We may have underestimated the effects of gravity on our cognition so far because gravity is so stable on Earth. It is arguably the most persistent sensory signal in the brain. I predict the next couple of decades will reveal a lot about how gravity has been affecting the way we think, feel and act – without us even noticing.</p>
<p>In the meantime, I am enjoying the ride – weightlessness is the best experience I have ever had. The pilots announce “3, 2, 1, INJECT”, and there you are floating. There are no bodily constraints, just effortless movements and unpredicted movements of your limbs that lead to euphoria, excitement and enhanced awareness of your body. It is very hard to sum up experience – I can only say it’s a feeling of awe and freedom.</p><img src="https://counter.theconversation.com/content/122359/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Elisa Raffaella Ferrè received funding from the European Space Agency (ESA), the European Low Gravity Association Research (ELGRA) and the UK Royal Society to conduct this research.</span></em></p>The constant pressure of gravity affects our thoughts and perception, but it’s so constant we haven’t noticed – until now.Elisa Raffaella Ferrè, Senior Lecturer, Department of Psychology, Royal Holloway University of LondonLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1192252019-06-30T19:30:31Z2019-06-30T19:30:31ZTo carve out a niche in space industries, Australia should focus on microgravity research rockets<figure><img src="https://images.theconversation.com/files/280923/original/file-20190624-97745-1i54qu6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Experiments performed in microgravity – like this one in the International Space Station by astronaut Samantha Cristoforetti – can give us data not able to be gathered on Earth. </span> <span class="attribution"><a class="source" href="https://www.nasa.gov/beta/content/esa-astronaut-samantha-cristoforetti-2">NASA</a></span></figcaption></figure><p>Australia now has a <a href="https://theconversation.com/ten-essential-reads-to-catch-up-on-australian-space-agency-news-108671">space agency</a>, and our federal and South Australian governments are looking to grow a prosperous space industry to boost productivity and employment. </p>
<p>The challenge for Australia is to find a niche in the expanding global race to commercialise space. </p>
<p>I suggest we should focus on microgravity experiments. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/australia-well-placed-to-join-the-moon-mining-race-or-is-it-111746">Australia: well placed to join the Moon mining race ... or is it?</a>
</strong>
</em>
</p>
<hr>
<p>First of all, let’s get the definition of <a href="https://www.nasa.gov/audience/forstudents/k-4/stories/nasa-knows/what-is-microgravity-k4.html">microgravity</a> right. </p>
<p>Micro means very small, so the term microgravity is used interchangeably with “Zero-G” or zero gravity.</p>
<p>If you’ve seen videos of people floating on board an aircraft known as the “<a href="http://www.novespace.fr/en,vol.html">vomit comet</a>”, they’re in microgravity. That doesn’t mean there’s no gravity; it means they are in freefall. </p>
<p>It’s the same sensation you may have felt at an amusement park, or in a fast-moving elevator when your stomach lifts up. </p>
<p>Objects in freefall are all falling towards something at the same speed. So in the vomit comet: the aircraft, the people and everything inside are all falling towards the ground at the same speed.</p>
<h2>A spherical flame</h2>
<p>Microgravity research makes use of that freefall condition to conduct scientific experiments. It’s particularly interesting to do so because most systems we understand well usually behave differently in microgravity. </p>
<p>For example, on Earth the flame from a struck match looks like an inverted teardrop shape and is orange. In microgravity, that same flame is spherical and <a href="https://www.space.com/13766-international-space-station-flex-fire-research.html">blue in colour</a>. This is because heat transfer is very different in microgravity than in normal gravity. </p>
<p>We learn in school that heat rises: this is what makes the match flame become pointed at the top – all the heat in the flame is rising upwards.</p>
<p>In microgravity, heat doesn’t rise. It stays exactly where it is. So the flame in microgravity keeps its heat focused around the match and burns much hotter, which is why it appears blue. </p>
<p>Understanding these simple processes allows scientists and engineers to design equipment for use in spacecraft, which experience microgravity all the time.</p>
<h2>Experiments at microgravity</h2>
<p>There are more than <a href="https://www.nasa.gov/mission_pages/station/research/experiments/explorer/">300 experiments</a> currently happening aboard the International Space Station, making it the largest off-world scientific laboratory. From biotechnology to earth and space science, and from physics to human research, we are continually finding out new things about our world from experiments in microgravity.</p>
<p>Scientifically, such experiments have great value. For example, crystal forms of a <a href="https://www.nasa.gov/mission_pages/station/research/experiments/explorer/Investigation.html?#id=1169">protein involved in the disease cystic fibrosis</a> – a life-threatening lung disease caused by a genetic mutation – can be grown in microgravity. Without the effects of gravity, the crystals grow much bigger and with higher purity. Researchers can use these “super crystals” to determine protein structure, and improve the drugs currently used to treat cystic fibrosis. More efficient drugs reduce the need for lengthy lab-based research and development and improve the quality of life of patients. </p>
<p>Data from observations of <a href="http://eea.spaceflight.esa.int/portal/exp/?id=9641">how liquid metals solidify</a> in microgravity has been used to change how we cast turbine blades on Earth. Changes to these models and processes has resulted in the manufacture of <a href="http://www.spaceflight.esa.int/impress/text/education/Circular%20Motion/Turbine_Blades.html">lighter and stronger blades</a> for aircraft engines. Lighter aircraft leads to lower fuel consumption and so less greenhouse gas emission resulting in reduced airfares to the consumer.</p>
<h2>Opportunity for Australia</h2>
<p>Australia has little involvement with the International Space Station and we don’t have a Zero-G aircraft. So we must look to other types of microgravity platform to conduct any research. </p>
<p>Up until the 1970s we <a href="https://theconversation.com/lost-in-space-australia-dwindled-from-space-leader-to-also-ran-in-50-years-83310">launched sounding rockets from Woomera, South Australia</a> – but as a defence project those flights stopped when other countries pulled out. </p>
<p>A sounding rocket is so-called from “sonda” the Latin word for “probe” – it’s a rocket that takes measurements. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/lost-in-space-australia-dwindled-from-space-leader-to-also-ran-in-50-years-83310">Lost in space: Australia dwindled from space leader to also-ran in 50 years</a>
</strong>
</em>
</p>
<hr>
<p>In 2019 the <a href="https://ayaa.com.au/">Australian Youth Aero Association</a> held the inaugural <a href="https://aurc.ayaa.com.au/">Australian Universities Rocket Competition</a> to boost new capability in sounding rocket technology in Australia. </p>
<p>The rocket launches with a rapid acceleration which lasts for a few seconds. After the motor has used up all its fuel, the rocket traces out a huge arc in the sky, where everything inside is in zero gravity before it falls back down to earth.</p>
<p>Because we only need the rocket to be in freefall to achieve microgravity, the rocket doesn’t even need to go into space to conduct the experiment. </p>
<p>This growing number of microgravity platforms available in Australia provides scientists with a new environment in which to <a href="https://www.rmit.edu.au/news/all-news/2019/apr/hive-rocket-team">conduct experiments</a>. </p>
<h2>Cost versus risk</h2>
<p>Student-built rockets are low cost – however, model rocketry is also high-risk, and not ideal for precise scientific measurements. If the safety parachute fails to deploy, the rocket risks a ballistic landing, destroying the rocket and everything on board – including that valuable scientific experiment.</p>
<p>Many nations have active sounding rocket programmes using reliable rockets that regularly launch to altitudes well above 100 km, the boundary that separates aeronautics from astronautics and the commonly accepted “<a href="https://en.wikipedia.org/wiki/K%C3%A1rm%C3%A1n_line">edge of space</a>”. </p>
<p>In Australia, <a href="https://ela.space/">Equatorial Launch Australia</a> (ELA) are working with The Gumatj Corporation Limited, Developing East Arnhem Limited and the Northern Territory Government to build Australia’s first spaceport. </p>
<p>The site in the Northern Territory is sufficiently well advanced that <a href="https://www.smh.com.au/business/small-business/world-first-startup-wins-nasa-deal-to-launch-rockets-from-australia-20190531-p51t8g.html">NASA recently announced</a> they would work with ELA to launch sounding rockets into sub-orbital space from the Arnhem Space Centre in 2020.</p>
<p>Thanks to the proximity of northern Australia to the equator and expertise in ground station operation, Australia has an opportunity to carve out a niche in launching sounding rockets to conduct microgravity research.</p><img src="https://counter.theconversation.com/content/119225/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>On Earth the flame from a struck match looks like an inverted teardrop shape and is orange. In microgravity, that same flame is spherical and blue. Heat transfer is different with minimal gravity.Gail Iles, Lecturer in Physics, RMIT UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1062562018-11-19T12:02:26Z2018-11-19T12:02:26ZWhat happens to the brain in zero gravity?<figure><img src="https://images.theconversation.com/files/246181/original/file-20181119-76150-1kiwh5n.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Canadian Space Agency astronaut Chris Hadfield on the International Space Station in 2012.</span> <span class="attribution"><a class="source" href="https://images.nasa.gov/details-iss034e010866.html">NASA</a></span></figcaption></figure><p>NASA has made a commitment to <a href="https://www.nasa.gov/mission_pages/mars/overview/index.html">send humans to Mars by the 2030s</a>. This is an ambitious goal when you think that a typical round trip will anywhere between three and six months and crews will be expected to stay on the red planet for up to two years before planetary alignment allows for the return journey home. It means that the astronauts have to live in reduced (micro) gravity for about three years – well beyond the <a href="https://arstechnica.com/science/2016/03/meet-the-real-ironman-of-spaceflight-valery-polyakov/">current record of 438 continuous days</a> in space held by the Russian cosmonaut Valery Polyakov. </p>
<p>In the early days of space travel, scientists worked hard to figure out <a href="https://www.space.com/26572-how-it-worked-the-apollo-spacecraft-infographic.html">how to overcome the force of gravity</a> so that a rocket could catapult free of Earth’s pull in order to land humans on the Moon. Today, gravity remains at the top of the science agenda, but this time we’re more interested in how reduced gravity affects the astronauts’ health – especially their brains. After all, we’ve evolved to exist within Earth’s gravity (1 g), not in the weightlessness of space (0 g) or the microgravity of Mars (0.3 g).</p>
<p>So exactly how does the human brain cope with microgravity? Poorly, in a nutshell – although information about this is limited. This is surprising, since we’re familiar with astronauts’ <a href="http://uk.businessinsider.com/how-body-changes-outer-space-2015-10?r=US&IR=T/#2-it-turns-your-muscles-into-jelly-2">faces becoming red and bloated</a> during weightlessness – a phenomenon affectionately known as the “<a href="https://www.npr.org/sections/thesalt/2012/02/23/147294191/why-astronauts-crave-tabasco-sauce?t=1542626100683">Charlie Brown effect</a>”, or “<a href="https://airandspace.si.edu/stories/editorial/astronaut-lingo-puffy-head-bird-legs">puffy head bird legs syndrome</a>”. This is due to fluid consisting mostly of blood (cells and plasma) and cerebrospinal fluid shifting towards the head, causing them to have round, puffy faces and thinner legs. </p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/5zld_7m2WWg?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
</figure>
<p>These fluid shifts are also associated with space motion sickness, headaches and nausea. They have also, more recently, been <a href="https://www.nejm.org/doi/10.1056/NEJMoa1705129?url_ver=Z39.88-2003&rfr_id=ori%3Arid%3Acrossref.org&rfr_dat=cr_pub%3Dwww.ncbi.nlm.nih.gov">linked to blurred vision</a> due to a build up of pressure as blood flow increases and the brain floats upward inside the skull – a condition called visual impairment and intracranial pressure syndrome. Even though NASA considers this syndrome to be the top health risk for any mission to Mars, figuring out what causes it and – an even tougher question – how to prevent it, still remains a mystery. </p>
<p>So where does my research fit into this? Well, I think that certain parts of the brain end up receiving way too much blood because nitric oxide – an invisible molecule which is usually floating around in the blood stream – builds up in the bloodstream. This makes the arteries supplying the brain with blood relax, so that they open up too much. As a result of this relentless surge in blood flow, the blood-brain barrier – the brain’s “shock absorber” – may become overwhelmed. This allows water to slowly build up (a condition called oedema), causing brain swelling and an increase in pressure that can also be made worse due to limits in its drainage capacity. </p>
<p>Think of it like a river overflowing its banks. The end result is that not enough oxygen gets to parts of the brain fast enough. This a big problem which could explain why blurred vision occurs, as well as effects on other skills including astronauts’ cognitive agility (how they think, concentrate, reason and move).</p>
<h2>A trip in the ‘vomit comet’</h2>
<p>To work out whether my idea was right, we needed to test it. But rather than ask NASA for a trip to the moon, we escaped the bonds of Earth’s gravity by simulating weightlessness in <a href="https://www.space.com/37942-vomit-comet.html">a special aeroplane nicknamed the “vomit comet”</a>. </p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/sHztOIm-XYA?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
</figure>
<p>By climbing and then dipping through the air, this plane performs up to 30 of these “parabolas” in a single flight to simulate the feeling of weightlessness. They last only 30 seconds and I must admit, it’s very addictive and you really do get a puffy face! </p>
<p>With all of the equipment securely fastened down, we took measurements from eight volunteers who took a single flight every day for four days. We measured blood flow in different arteries that supply the brain using a portable doppler ultrasound, which works by bouncing high-frequency sound waves off circulating red blood cells. We also measured nitric oxide levels in blood samples taken from the forearm vein, as well as other invisible molecules that included free radicals and brain-specific proteins (which reflect structural damage to the brain) that could tell us if the blood-brain barrier has been forced open. </p>
<p>Our initial findings confirmed what we anticipated. Nitric oxide levels increased following repeated bouts of weightlessness, and this coincided with increased blood flow, particularly through arteries that supply the back of the brain. This forced the blood-brain barrier open, although there was no evidence of structural brain damage. </p>
<p>We’re now planning on following these studies up with more detailed assessments of blood and fluid shifts in the brain using imaging techniques such as magnetic resonance to confirm our findings. We’re also going to explore the effects that countermeasures such as rubber suction trousers – which create a negative pressure in the lower half of the body with the idea that they can help “suck” blood away from the astronaut’s brain – as well as drugs to counteract the increase in nitric oxide. But these findings won’t just improve space travel – they can also provide valuable information as to why the “gravity” of exercise is good medicine for the brain and how it can protect against dementia and stroke in later life.</p><img src="https://counter.theconversation.com/content/106256/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Damian Bailey is supported by a Royal Society Wolfson Research Fellowship (#WM 170007).
This research was supported by a grant from the Centre National d'Etudes Spatiales (CNES).
Damian Bailey is a grant reviewer for the European Space Agency.</span></em></p>New research has uncovered exactly what happens to the brain when astronauts are in space.Damian Bailey, Professor of Physiology and Biochemistry, University of South WalesLicensed as Creative Commons – attribution, no derivatives.