On June 5, 2024, astronauts Butch Wilmore and Suni Williams left the Earth for the International Space Station. The mission had been delayed for seven long years thanks to various technical setbacks and other problems. The length of the mission was to be 8 days. Then something happened.
The astronauts were using something called the Starliner capsule, made by Boeing, to get them to and from the ISS. Except the capsule has been suffering from issues like helium leaks and thruster issues. Boeing has been suffering numerous failures with its aircraft for years now.
The return of the astronauts has been delayed while the capsule is assessed to see if it’s safe for them to use. If not, they may not return to Earth until February 2025 with the crew from the next SpaceX mission.
Everyone’s hoping it works out for the best, but that could mean these two astronauts, scheduled for just over a week, will end up spending 7 or 8 months in space. And long term stays in space come with side effects.
Space has no shielding from cosmic radiation the way Earth does. Our atmosphere protects us from a hell of a lot, but galactic cosmic radiation in space can pass right through spacecraft walls and human bodies. A normal stay in a shuttle or the ISS is not too dangerous as they are meant to be short trips, but the longer someone stays in orbit, the longer they’re going to be exposed. It’s just one of the issues that they’ll have to deal with.
When you’re not on Earth, it’s hard to get access to the things the rest of us take for granted. While it’s easy for us to go to a 7-11 to get a Slurpee, that’s not an option for an astronaut. And, in their cases, it’s less frivolous things than Slurpees they might need like medicine, food, water, and even air. None of these are just lying around up there.
Imagine something happens to your supply of food, air, or water just as you reach Mars. It takes 9 months to get there, so turning around to pick up something you need is not an option.
Mental health is a concern that NASA has in regard to astronauts isolated away from Earth for so long. In the case of the two astronauts stranded on the ISS, it’s likely to be worse since this was never planned. But even when it is a planned mission, or when we look ahead to extended missions to Mars, this is going to be a real concern.
Another major concern is how space physically affects the human body. We’re not designed to live in a gravity-free environment. This affects organs, bone density, vision, and more. Astronauts who come back after extended stays in space have had some pretty concerning health issues as a result.
There are even a few sci-fi-sounding issues that astronauts need to deal with on extended missions. The current US record for time in space is 371 days, while a Russian cosmonaut made it 437 days. All of that resulted in changes in everything from the astronaut’s brain to the bacteria in their stomach. NASA has identified 30 health risks associated with missions in space. Let’s dive into a few more closely.
Cosmic Radiation Dangers
It’s estimated that, on a three-year Mars mission, astronauts could be bombarded by enough ionizing cosmic radiation to cause serious cellular and DNA damage. Right now we have no idea just how much radiation, what kind of radiation, or how damaging it could potentially be since no one has traveled that far for that long.
Potential side effects could be cancer, infertility, cataracts, and more. Research into exposure to cosmic radiation has concluded that cancer and degenerative diseases are to be expected, as in they aren’t just maybe unlucky potential side effects. They’re going to happen.
Astronauts will be in contact with ionizing radiation between 50 and 2000 millisieverts (mSv.) One mSv is what you’d get from three chest X-rays. One thousand causes radiation sickness like vomiting and hemorrhaging.
Isolation and Mental Health
As if radiation wasn’t bad enough, space also wreaks havoc on the mental health of astronauts. Imagine being trapped in a place you literally cannot leave, for months at a time, and you’re all alone. Or you’re stuck with one other person who you didn’t even know before it started. How long before you start to lose your cool?
Astronauts have been diagnosed with a condition psychologists call the “break-off effect.” It’s characterized by a sensation of feeling detached from the earth, like you’re no longer a part of it, and was identified as far back as the 1950s with high-altitude pilots.
Some astronauts find themselves feeling attached to the craft they are in instead of the Earth. Alan Shepherd, the first American in space, said that when he looked out at the Earth, he felt nothing. He thought it was underwhelming and insignificant but lied and said it looked beautiful because he knew that’s what everyone wanted to hear.
Shepherd lied about his experience, and it’s something that astronauts are known to do. Psychologists have noted that astronauts are fearful of expressing their true feelings because they don’t want to be considered mentally unwell. In truth, many of them feel loneliness and disconnection from the Earth and are more interested in their vehicle than the planet they just came from.
Beyond these unique problems associated with space, astronauts are also subject to the same feelings that anyone on Earth would have if they were stuck in an isolated situation. Anxiety, depression, sadness, and more. The problem is that they often don’t have anyone else to talk to about it, and nowhere to go to change their surroundings.
The Dangers of a Lack of Gravity
Back when space flight was first being considered, one of the chief concerns about how we would adapt to zero gravity situations was the ability to eat and drink. To this day you can find lots of articles and videos about the novel ways NASA has come up with to ensure an astronaut can enjoy Tang in space. Turns out, eating and drinking were one of our least concerns.
In a zero-gravity environment, the human body suffers from a loss of bone mineral density. On Earth, your bones, like all your other cells, are constantly changing and growing. They react to the stress that they’re under all the time. The problem is, in space, they’re not under that stress anymore. Because gravity isn’t putting strain on your bones, as they grow and change while you’re in space they don’t need to be as strong. Your bones begin to grow weaker the longer you’re up there because nothing is stressing them out anymore.
After too long in space, your bones can become exceptionally weak. That means, if you do endure some kind of stress, you’re more prone to breaks and fractures. When you return to Earth, the stress of gravity weakens you a lot. It’s not just your bones either, it’s your muscles that have degraded because they’re not working against the force of gravity. There’s fear that, after a mission to Mars, an astronaut in their 30s would feel as weak as a person in their 80s when they got off the craft, even after exercising regularly.
Once astronauts get to Mars they have to deal with that shift in gravity from their module to the planet itself. Coming from Earth and returning to Earth means that there are three different gravities that their bodies are going to have to adapt to you. This can cause space motion sickness on top of muscle and blood pressure issues.
When Frank Rubio returned to Earth after his 371 days in space, he had to be lifted out of the capsule because he didn’t have the strength to get out on his own.
In space, astronauts have to exercise up to 2 hours a day, every day, to prevent their muscles from atrophying. This includes their hearts which all diminish due to the lack of gravity. Astronauts who have returned from zero gravity have shown an inability to maintain blood pressure when they sit up and insufficient blood flow to the brain.
Another issue astronauts face is fluid pooling behind their eyes, the eyeball flattening out, and swelling of the optic disc. The lack of gravity leads to serious vision issues dubbed Space-Associated Neuro-Ocular Syndrome. Astronauts on extended missions have had to get glasses with stronger prescriptions as their vision begins to fail them. Some of these changes are permanent.
Stomach bacteria suffer in zero gravity. After returning to Earth it’s been observed in astronauts that the amount of helpful stomach bacteria has decreased while more pathogenic bacteria increased. This one needs more study to figure out what’s happening and if it’s a potential danger, however. It’s not the weirdest side effect of being in space, though.
Time Dilation and Aging
Time dilation is a real thing, not just something cooked up by Star Trek writers. It’s also something that has affected real astronauts here in the present. It’s not nearly so dramatic as anything you’ll find in a cool space travel story but it’s not nothing, either. Specifically, astronaut Scott Kelly went to space while his twin brother Mark stayed on Earth. Thanks to time dilation, the gap between their ages increased, and Mark aged a little more than Scott did.
The numbers here are extremely insignificant because we have not mastered exceptionally fast space flight yet and can’t do any of that “almost light speed” stuff that would allow someone to travel for a month while years pass on Earth. That said, Mark Kelly is now 5 milliseconds older than Scott compared to before he went to space.
As Einstein once explained, the closer you get to the speed of light, the slower time goes. Scott Kelly was not going anywhere near light speed, but he was orbiting the earth at 17,500 miles per hour which is faster than most of us will ever go and he was not as close to the gravitational pull. After a year in space, he shaved off 5 milliseconds.
If we could travel at light speed, the time difference would be far more significant. Light speed itself can never be achieved according to physics, as time would then stop entirely and that seems counterproductive. But what if we got close? At 99% of the speed of light, if you went on a 5-year trip in space, 36 years would pass on Earth. At 99.99999999% light speed, one second of travel equals 19.6 hours on Earth. One month at that speed would mean 5,876 years passed on Earth.
For long-term space travel, the time dilation would clearly leave the entire world behind. Imagine Star Trek’s five-year mission if they could achieve near-light speeds which their warp engines supposedly do. That 5-year mission at warp one would pass while 352,000 years passed on Earth.
Back in reality, time dilation can still have curious side effects. Because of how gravity affects time, an astronaut on Mars could live there for 80 years but die 12 seconds earlier than they would if they lived the exact same 80 years on Earth.
It’s not your speed that affects time dilation, but gravity as well. That means, if you were away from the gravitational pull of a planet and traveling through space at a normal speed, that is something well below the speed of light, time would end up moving slower for you than it would for people on Earth. That’s why high-orbit satellites age faster than those closer to Earth’s gravitational pull.
More gravity means slower time. On a planet with high gravity, or like in the movie Interstellar where the planet is near a black hole, time would seem to slow down compared to time on earth.
As bizarre as all of this sounds, and it seems like it doesn’t make sense, it’s been proven many times over. Experiments with atomic clocks have shown time does slow down if you move away from a source of gravity. You can set up two precise clocks at the exact same time, lined up perfectly down to the microsecond, and the one that travels around the world will come back at a different time.
Will time dilation be a big deal for any astronauts in our lifetime? Probably not. Maybe one day, if we develop an engine capable of near-light speed or somehow faster than lightspeed travel. Until then, we’re just dealing with fractions of seconds. Not the end of the world, but certainly interesting nonetheless.
Given all the horrible things that extended space travel can do, it’s nice to know that there’s at least one that’s just a little bit goofy but not dangerous.