What astronauts and astronomers say about living in space

19 March 2023 - 00:00 By Veruska De Vita
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Astronaut Scott Kelly
Astronaut Scott Kelly
Image: Wikipedia Commons


Astronaut Scott Kelly spent 340 days in space. With an identical twin brother on Earth, scientists had a perfect control subject with which to monitor the changes in Kelly’s body. Urine, stool and blood samples were taken daily, showing how his DNA and telomeres — caps that protect the ends of chromosomes — were breaking. During the first days in space his ankles swelled to the size of basketballs and outside of the Earth’s protective atmosphere he was exposed to radiation equivalent to having five X-Rays a day. Kelly is one of a few handfuls of astronauts who have spent close to a year or more in space and has first-hand experience on what it does to the body.

Living in microgravity causes body fluids to rise to the head, changing the shape of eyeballs so that a number of astronauts experienced changes in eyesight. Even with two hours of exercise a day, muscles atrophy and the heart weakens. One astronaut developed a clot in his neck and when doctors examined further they found that his blood was flowing in the opposite direction.

Life in space is not for sissies, yet the hold that this predominantly unknown territory has on those exploring it is far greater than any gravitational pull the Earth exerts. Albeit with sacrifices, for these chosen few, the idea of floating in space is preferred to being earthbound.

Deana Weibel is a religious anthropologist who interviews astronauts about their religious experiences in space, with many of the conversations spilling into other aspects of life, such as mental and emotional shifts. While she keeps the identity of those in the space programme secret, she explains that many of them experience the overview effect — where being off Earth and seeing it from that vantage point pushes a different understanding of life, the universe and God.

“Many of the astronauts I’ve spoken to describe the sensation of being in space and looking at Earth as overwhelming. It’s a God-like view that humans aren’t supposed to have, a secret knowledge. Astronaut Ed White experienced moments of feeling shaken, and his understanding of things shifted. He was seeing Earth from space in an unfiltered way. Another astronaut described Earth as this glowing blue planet with islands and clouds, greens and browns, how it’s clearly alive. They noticed how thin the atmosphere is, wafer thin, how fragile it is and the idea that we’re interfering with the atmosphere is frightening. It’s a thin blue line and that’s the entirety of it and we’re messing it up and there’s nowhere to go,” says Weibel.

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Adaptation to darkness is another major life-altering occurrence. “Astronauts who orbit the moon are not just looking at Earth but into outer space, so they become dark-adapted. There is an opening of the mind that can happen because they get to see out and see clearly. An astronaut who was on the dark side of the moon, the side not facing Earth, where Nasa can’t communicate, switched off the equipment lights and looked out. Once his eyes dark-adapted all he saw was a solid sheet of light. There were so many stars that he couldn’t see between them. The idea that there is no life anywhere else seemed ridiculous to him,” explains Weibel.

Going into space can bring about depression. There is a general pattern where for the first few days mood goes up and then, after a while when the excitement wears off, it steadily decreases. Christina Hammock Koch who spent 328 days aboard the International Space Station, missed the wind on her face and running on the beach with her dog. “Koch had a physical craving for certain sensations that you can’t get in space. Up there you don’t have access to things that give you feelings and sensations so there’s a chance for depression. Gut bacteria have an effect on emotions and this would affect one’s mental state. We get gut bacteria from our mother and then from what we eat. In a sterile environment how would bacteria live, what would radiation do to it?” Weibel extrapolates.

Weibel interviewed an astronaut who believes that human life came from space, that we are descendants of another spacefaring species that arrived on Earth and set us up. Earth was obviously the perfect choice for survival and evolution, but what other planets out there would be able to support life as we know it?

Finding an Alternative Earth

Recently, a group of 50 astronomers confirmed the existence of an exoplanet that’s similar in size and mass to Earth and close enough to its sun for liquid water to be on its surface. Named Wolf 1069 b, it is 31 light years away, meaning it would take us more than a billion years to get there. Still, for scientists searching for life among the galaxies, the discovery of a new terrestrial exoplanet is exciting. 

An artist's rendition of Wolf 1069 b.
An artist's rendition of Wolf 1069 b.
Image: Wiener Zeitung

On home soil Daniel Cunnama, science engagement astronomer at the South African Astronomical Observatory, explains that for a planet to be the ideal living area for humankind and other earthly species, there needs to be an abundance of water. There’s a fine temperature range where liquid water can be present, between ice and boiling point. To work out the surface temperature of a planet, astronomers find the temperature of a star, which is essentially a sun, and then measure the distance of a planet from that star. For a planet to have consistent water on or near its surface means that it needs to be in a comfortable orbital region to its star. This region is called the habitable zone.

The other non-negotiable, although a complicated one, is atmosphere. There needs to be oxygen so that we can breathe. Plants needs carbon dioxide for photosynthesis. Earth’s atmosphere is like a blanket that keeps us insulated. It mediates temperature and provides protection against gamma-rays, X-rays and UV-rays.

Daniel Cunnama
Daniel Cunnama
Image: YouTube

The geological environment needs to be stable; there can’t have volcanoes going off all the time. Earth has provided gentle tectonic plates and a stable environment for billions of years to sustain life and support evolution. Everything on our planet has evolved to survive Earth’s gravity. Moving to a planet with more gravity is problematic; it would crush us and we wouldn’t be able to build much. One with less gravity would not be sustainable in the long term.

Cunnama believes that we’ll see humans on Mars in the next decade. “It will be a lunar landing situation where they will go and return and then there will be a more permanent base on Mars, similar to the International Space Station set-up. But there is a lot of consideration that goes into a permanent base. There would need to be resupply missions as they wouldn’t be completely off-grid and growing their own food. People won’t be living on Mars for longer than a year or two,” he says.

In terms of having a thriving community on Mars, this would not be possible with our current technology. Survival yes, but not more. Mars is not really conducive to life. It has water but not a lot. It has huge temperature swings, harmful radiation and going outdoors without a strong spacesuit is a no-no.

“We have the technology to survive on Mars, we can survive at the south pole, we can survive in space, but it’s not easy. To terraform Mars to support life as we know it would take millions and millions of years. As the saying goes: there’s no planet B. Not in the foreseeable future,” attests Cunnama.

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Is there life on other planets?

Andrew Chen, professor of astrophysics at the University of the Witwatersrand, has a passion for knowledge of extreme environments close to black holes. He explains that what attracts him and other scientists to outer space is its mystery. It’s the unknown. From a scientific perspective, the information that can be found by remote sensing instruments and telescopes has dramatically increased what we know about our galaxy and others. According to Chen, the data — including images and soil samples — we get from uncrewed rovers is a lot more precise and valuable than if we were to send manned craft.

“It’s a very exciting area of study at the moment, seeing if planets around other stars within our galaxy can support life; not just human life, but any life. Of course life on another planet will look different to life on ours. We now know that the stars in our galaxy, almost all of them, have planets. If their orientation is favourable we can detect those exoplanets and learn about them. The stars are far away and it would take a long time to physically get to them but we’re looking at them. Using powerful telescopes like James Webb we can look at the spectra of the atmospheres of these exoplanets to see if they have oxygen or organic compounds. That would be the smoking gun for the presence of life,” says Chen.

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