Two space travelers on the International Space Station are entering rarely tread territory as they pass the six-month mark in a year-long stay in orbit. The mission will help scientists understand how humans might cope with a journey to Mars.
American astronaut Scott Kelly and Russian cosmonaut Mikhail Kornienko have been living on the space station for about six months and won't be going home for another half-year. Compared to typical astronauts, they're spending twice the time away from friends and family, twice the time in weightlessness, and twice the time exposed to space radiation — and experiencing twice the dose of physical and mental stress.
"I feel pretty good overall," Kelly said Monday in an interview on NASA TV. "I definitely recognize that I've been up here a long time and have just as long ahead of me. But I feel positive about it."
Kelly added that he has consciously paced himself more slowly on this mission than on his last trip into orbit, which put him on the orbiting laboratory for 159 days.
"I intentionally thought about ways for me to get to the end of this with as much energy as I had in the beginning," Kelly said. "I intentionally don't work at the same pace I did last time I was up here, when I felt like I could go at 100 percent speed for the full six months."
If humans were to take a trip to Mars using near-future technology, the journey would likely take more than one year each way. With this one-year mission, scientists will get their hands on a massive haul of data revealing the physical effects of long-duration spaceflight.
While the results of the scientific studies on Kelly and Kornienko will not be revealed until after the mission is over, Kelly said he has taken note of how his body has adjusted to life in microgravity.
"It gets less significant over time, but I do notice that I can do things now that I couldn't do right when I first got up here, even though I had flown 180 days in space before," Kelly said. "My ability to move around is really improved over time and continues to improve. And, you know, you just get more comfortable. Your clarity of thought is greater. Your ability to focus. Things like that."
While a one-year mission on the International Space Station is no easy task, it is certainly very different from a trip to Mars. Space travelers on a journey to the Red Planet would travel through millions of miles of empty space, far from home and locked up with the same group of people for the entire trip.
The astronauts on the orbiting station have it somewhat easier: They can see Earth. They have a relatively quick way to get home if the need arises, and their crewmates change from time to time.
But Kelly and Kornienko will experience some of the mental strain of a Mars mission while they are on the station, including not being able to go outside (except during spacewalks, which aren't exactly a walk in the park).
"This is a very closed environment. We can never leave. The lighting's always pretty much the same — the smells, the sounds, everything's the same," Kelly said yesterday. "I think even most prisoners can get outside occasionally in a week. But we can't. And that's what I miss, after people."
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