Astronauts typically stay at the International Space Station for six months at a time. During those expeditions, they run experiments to study the effects of different scientific principles in space. Being in space can be physically taxing, however. What does being in space for so long do to the bodies of the men and women at the Space Station?
One risk astronauts face in the ISS is a risk to their vision. The Prospective Observational Study of Ocular Health in ISS Crews is a research study that seeks to understand more about risk to ocular health in space, and find ways to limit risk. Factors such as pressure differences in the Space Station and increased intracranial pressure of the astronauts may have an effect on eyesight and the central nervous system. The Ocular Health team is regularly performing tests on the astronauts for things like blood pressure, visual acuity, ability to see contrast, and the pressure in the eye itself. These tests can be done in space, while the astronauts are at the Space Station. The astronauts can perform the tests on themselves, or be trained to do the tests on each other. The Ocular Health team hopes to learn more about the eye through studying the astronauts. NASA wrote on its website that the information gleaned from this initiative might even apply to glaucoma research, and other conditions caused by high intracranial pressure.
Another problem on the space station is decreased bone and muscle density. In environments with lower gravity, bones and muscle tend to deteriorate to some degree. To learn more about the changes that occur during a mission in space, scientists are planning to introduce a very small MRI machine that astronauts can take with them onto the space station. The MRI machine is expected to be ready to fly in 2016.
"We don't know how bone and muscle density change with time during a mission. You can only guess with the before and after data we have today," said Gordon Sarty, a researcher at the University of Saskatchewan in Canada.
Space walks are another issue. The space suits astronauts need to wear outside of the space station contain pure oxygen. The astronauts need to deplete their bodies' supply of nitrogen before leaving the station, because nitrogen can bubble up when astronauts walk in space, causing joint pain. The astronauts need to wear the suits for a few hours inside the station before going on the walk to avoid these gas bubbles.
