Space Twin Experiment Set to Answer NASA's Biggest Question

While NASA already knows many of the affects on the human body while in space, when astronaut Scott Kelly launches for the beginning of his year long mission at the International Space Station, he has one long-range goal on his mind.

"We're trying to get to Mars," Kelly says. "I won't go, but the next generation has a chance."

There are many challenges facing NASA if it wants to reach Mars, the fourth planet from the Sun and the only other body in the solar system that even remotely resembles Earth, with ice caps and even a thin atmosphere. It must design new complex vehicles that can not only fly people there, but also land them safely once they arrive. For this type of mission, it must build a political consensus for such a mission and acquire billions of dollars in funding.

But even if NASA does in fact accomplish all of these other goals, there still remains an array of threats to the health of the astronauts that undertake such a mission. Beyond the safety net of Earth's atmosphere, radiation could damage their bodies and extended periods in the absence of gravity weakens muscles and bones and some male astronauts have returned with impaired vision. On top of that, there are the psychological effects that must be considered. Astronauts will be spending a long time in a very tight space far from home in a large, unknown environment

For more than a decade, astronauts have been living and working in space for six months at a time, allowing scientists to begin to answer many of the questions regarding health. Now, they intend to further their study with Kelly spending a full year on the station while his twin brother, remains here on Earth.

Both during his time in space and after he returns to the ground here on Earth, researchers will perform various health tests on both Kelly and his twin brother in an effort to assess the impact of the human body while in space for long periods of time.

After its work on the space station NASA already has a pretty good understanding of many health issues and has instituted many specialized exercise programs using special equipment to keep their astronauts healthy. In many cases, the astronauts return in better shape than the day they launched.

Based on their studies, scientists believe that most of the physical problems actually occur during the first few months of spaceflight. During Kelly's mission, he will give them a chance to test that theory so NASA can be preparations for a future mission to Mars.