NASA announced last week that it plans to hire new astronauts for its Mars and International Space Station missions. But before you fill out your application, bear in mind that space travel has some serious downsides, especially when it comes to your health.
Being stuck in a tiny, microgravity spacecraft for months (or in Scott Kelly's case, a full year) can seriously mess with an astronaut's body and brain.
Scientists have found that the physiological stresses of space travel can lead to significant brain changes. While more research is needed to fully determine how the brain adapts to a microgravity situation, two ongoing studies are shedding light on the neurological challenges of space travel.
A recent NASA study used MRI and functional MRI to investigate the brains of astronauts before and after spending six months on the International Space Station. The scientists also gave the astronauts certain motor tasks to complete while aboard the station.
So far, they've found that a microgravity environment can lead to changes in brain structure and take a serious toll on astronauts' ability to think. The astronauts have had a more difficult time completing mental tasks and with physical coordination during and after spending time aboard the ISS.
Another study -- funded by the European Space Agency and the Russian space agency Roscosmos -- found that the brain's cortex reorganizes itself to adapt to the challenges of a long-duration spaceflight. The preliminary findings, published in the journal Brain Structure and Function in May, are part of a research project that will continue through 2018.
Study co-author Angelique Van Ombergen, a Ph.D. student in neuroscience at the University of Antwerp, said space is a very challenging environment for humans, so spaceflight can impact physiological systems in the body.
"Factors that can have an impact consist of, but are not limited to, weightlessness, cosmic radiation, isolation, confinement and disturbed day-night rhythm," Van Ombergen told The Huffington Post. "As one can imagine, all these factors can have an impact on the human brain, as they are new, challenging and stressful."
Researchers placed 16 astronauts in an MRI scanner before and after their space missions, examining changes in the brain's connectivity and neural networks. While the research continues, the evidence so far suggests that some areas of the brain can be altered in structure and function after a long space mission. The findings are based on how the body may receive conflicting signals while in space.
For instance, while an astronaut's inner ear may tell the brain that the body is falling, there is no visual input to suggest falling since the astronaut is in an environment with microgravity. Or, the increased fluid in the head may send a signal that the body is up-side down, but there's no up or down in space.
After spaceflight, "we found less connectivity strength in several motor- and vestibular-related areas, which we know that they are responsible in movement and balance," Van Ombergen said. "This could explain why astronauts typically present with temporary movement problems (problems with walking, gait and posture) and vestibular/balance problems (dizziness, vertigo, nausea) when returning to Earth."
Despite these and many other conflicting signals, it only takes a few days for the brain to adapt to the hostile space environment, which it usually does successfully.
"However, it’s a difficult task," Van Ombergen said.
If astronauts are sent on missions to Mars, these types of research projects will be necessary to help maintain their health during and after spaceflight.
"Our results are preliminary, but very promising and interesting," Van Ombergen said. "This is the first experiment ever investigating the effect of spaceflight on the human brain and we’ll collect more data over the coming years."