Medicine and Physiology for Mars Travelers
A trip to Mars provides challenges both for providing medical care and for maintaining health. The site, The Critical Path Roadmap, provides a listing of key questions that need to be answered to allow for a safe trip to Mars.
Three key areas standout as being particularly important. One is calcium loss from bone. Long-term exposure to microgravity leads to a on-going loss of bone calcium. This image, Calcium Loss in Space, shows a graph compiled by the Life Sciences Data Archive at the NASA Johnson Space Center. The graph shows that exposure to weightlessness increases the amount of calcium leaving the body. The high levels of calcium in the urine increase the risk of kidney stone formation and the loss of calcium from bones weakens the skeleton. Various methods have been proposed to prevent this loss, including the use of drugs, exercise and artificial gravity.
Another important area for concern is radiation exposure. The atmosphere and magnetic field of the Earth provide considerable protection against space radiation. When traveling between planets, this protection is lost and protection from radiation must be designed into the spacecraft. Two kinds of radiation are important in space. Solar particle events are intense bursts of radiation produced by solar flares. These events occur rarely, but when they do the radiation produced could be fatal to unprotected crewmember. The site, Solar Particle Events and the International Space Station, leads to a chapter produced by the National Academy of Sciences that explains the risks associated with solar particle events.
The other kind of radiation experienced in space is galactic a cosmic radiation. This radiation is a low-level radiation that occurs throughout the universe. The particles, while few in number compared to the number of particles that would be seen with a solar flare, contain a tremendous amount of energy. The long-term effects of exposure to this type of radiation are not well understood. The site, Radiation Hazards, goes to report produced by the National Academies that summarizes the radiation hazards that exist for crews traveling between planets.
This Quicktime movie, Cloud chamber, shows the radiation that exists around us on Earth. High energy particles pass through the cold vapor in the cloud chamber and leave a visible track.
Experience from previous long-duration space flights and from analog situations, such as in Antarctic exploration, have shown that psychology is a critical factor in the success of a long-duration mission. The site, Bold Endeavors, provides information on a book summarizing some of the key lessons learned from both polar and space exploration.
Medical Care will also present a challenge on a long duration mission. Crews will be selected to be healthy, but unanticipated events can arise. If this should occur, it is unlikely that the crew will have recent experience in dealing with similar problems. They will need diagnostic and training tools to allow them to train for anticipated problems and maintain proficiency. The site, Smart Medical Care, provides information on the projects that the National Space Biomedical Research Institute is undertaking to help with this problem.
Here's a recent article about the medical and physiologic issues raised by a human mission to Mars entitled, Preparing for Mars: The Physiologic and Medical Challenges