Living in microgravity, where we are exposed to just a few inches of the vacuum of outer space, can have serious effects on the human body.
Most astronauts spend only six months at a time in the environment of the International Space Station (ISS), which hovers 400 miles above Earth.
However, on March 27, NASA and the Russian Federal Space Agency sent three astronauts to the ISS. They will be the first astronauts to spend consecutive days in space.
The tests performed on these astronauts will bring us closer to understanding what can happen on longer space exploration missions, such as visits to Mars, which can take at least six months each way.
It may sound like a long time, but this year-long journey is not for the faint of heart. Scientists know a few things about how staying in microgravity for six months affects the human body, and some of them are downright alarming.
1. Straighten your spine
Astronauts can grow up to 3% taller in space. That means a 6-foot-tall astronaut could grow an additional two inches.
Growth spurts occur because microgravity allows the squishy discs between the vertebrae to relax and expand, much like releasing the pressure of a spring. It will take several months for them to return to their normal height after returning to Earth.
2. Turn your muscles into jelly
You don’t need muscles to support your body in zero gravity. The astronaut’s muscles begin to contract almost immediately, shedding excess tissue that is no longer needed.
Exercise is therefore important on the ISS so that astronauts can maintain the muscle mass they need when they return to Earth.
Typically, I spend about 2 hours per day exercising. This includes “weightlifting” using special resistance machines, since free weights have no weight in zero gravity. Below you can see the crazy equipment used to perform squats.
3. Your face becomes swollen.
Our bodies are mostly liquid. Gravity on Earth pulls that fluid down, and some of it collects in our lower legs. At near-zero grams, the liquid spreads more evenly around the body, making the astronaut’s face look more swollen than normal and his legs look thinner than normal.
After a few weeks, your body will adjust to the change in gravity and some of the swelling will go away.
4. Bone density decreases
If astronauts don’t exercise regularly, they can lose about 1% of their bone density each month they spend in space. So, like people with osteoporosis, they are much more likely to break bones when they return to Earth.
Exercise and proper nutrition are essential to minimize this effect. That will be especially important for astronauts who spend an entire year in space.
5. May cause visual impairment
A 2013 study examined the eyes of 27 astronauts who spent an average of 108 days on the ISS. NASA researchers have discovered that many of those who returned from space have abnormalities in their eyes. MRI scans revealed that nine of the astronauts had swelling around their optic nerves, and six of the astronauts had physically flattened areas at the back of their eyes.
While this is definitely a cause for concern, no serious vision problems have been reported among astronauts. NASA is conducting a more comprehensive follow-up study.
6. Confuses the immune system
Living in space can weaken astronauts’ immune systems, according to research published in 2014.
“Radiation, microbes, stress, microgravity, altered sleep cycles, and isolation all affect crew members’ immune systems,” Brian Crucian, a NASA biological research and immunology expert who led the study, said in a statement. It could have an impact.” “If this situation persists on long-duration deep space missions, it could increase the risk of infections, sensitivities, and autoimmune diseases in exploration astronauts.”
That means astronauts who plan to spend a year in space may be more likely to get sick.
The study found that while astronauts living in space have not shown any symptoms so far, their weakened immunity also means that old latent viruses like chickenpox may reawaken. It has been found.
Some immune cells taken from astronauts living in space are actually overly aggressive rather than suppressed, explaining why some astronauts develop rashes and other allergic reactions There is a possibility.
7. Your sleep cycle is messed up.
Astronauts must strap themselves into their sleeping bags every night. In microgravity, your head rotates forward and your arms lift up when you fall asleep.
Strange positions are difficult to get used to.
“Sometimes I wake up in the morning and see an arm floating in front of my face and think, ‘Oh my god, what is that?’ Until I realize it’s mine,” says astronaut Marcia. Ivins told Wired.
But there are many other obstacles that make it difficult to get quality sleep in space. A brilliant flash of light illuminates the space station every time a cosmic ray passes by.
Astronauts now have individual sleeping pods that help block some of that light. Still, studies have found that despite an 8.5-hour schedule, most astronauts only get about 6 hours of sleep.
8. Coordination breaks down
Returning to Earth after six months in microgravity is a daunting task. While in space, astronauts lose their clear sense of up and down. This is because in zero gravity, your vestibular system cannot tell where the ceiling is and where the ground is.
Although the body eventually readjusts, the astronaut is initially a little unsteady on his feet.
9. Senses become confused
When the pressure in a space changes, fluids move through the body. The same effect that causes an astronaut’s face to swell is bloodshot.
“It’s like a cold or allergies,” astronaut and physician Scott Parazynski told Scientific American. “A stuffy nose definitely dulls your sense of smell, which in turn dulls your sense of taste.”
Many astronauts report that food tastes much duller in microgravity, so they crave food with lots of extra flavorings and spices to compensate for the bland taste. Foods and drinks that rely on the sense of smell to derive flavor, like coffee, are a disappointment in space.
10. It’s mentally taxing
On the ISS, astronauts are literally a world away from the familiar, and they can’t just pack up and leave whenever they want.
Astronauts undergo rigorous psychological testing before they begin their training in space. Still, feeling isolated and confined is a big risk. Combine this with sleep deprivation, lack of gravitational comfort, and desensitization, and you can imagine how mentally taxing a long spaceflight can be.
Many astronauts say this was the most difficult task they’ve ever done.
11. Nutrition becomes difficult
Not getting the right nutrients can make almost all of the effects listed above worse.
Vitamin D is a concern for astronauts, said Sarah Zwart, a senior NASA scientist who studies the nutritional effects of long-term spaceflight. This is because vitamin D is not exposed to sunlight, making it easy to become deficient.
Specifically, Zwart told Business Insider that astronauts need large amounts of antioxidants because oxidative stress is much greater in space. Spaceflight also causes changes in iron metabolism. Astronauts’ iron levels are elevated because their red blood cell mass is reduced.
Astronauts track their food intake weekly to ensure they are maintaining proper levels of nutrients. Iron levels usually return to normal a few months after returning to Earth.
12. Exposure to dangerous space radiation
Cosmic radiation doesn’t give you superpowers like the Fantastic Four. A single dose can destroy the DNA itself, and the damage can cause cancer, cataracts, and other diseases.
Earth’s atmosphere acts as a force field that protects us from 99% of cosmic radiation, but astronauts don’t have the same protection in space. According to the European Space Agency, the radiation risk increases approximately 30 times.
While on the ISS, astronauts wear dosimeters that measure how much radiation they are exposed to. Their careers as astronauts are limited based on their exposure.
Scientists don’t know much about what happens after six consecutive months in space. Some of the impacts may remain the same, some may worsen, or new impacts may emerge. NASA’s year-long space mission is critical to understanding the risks of long-term human missions to the Moon and Mars.
Still, all of this is much better than somehow floating freely outside the space station, without a spacesuit, with scientists predicting you only have two minutes left before you die.
