Traveling to Mars
How dangerous is it out there in space? We know that space radiation between Earth and Mars presents a danger to astronauts. “It’s a question of radiation,” says Frank Cucinotta of NASA’s Space Radiation Health Project at the Johnson Space Center. “We know how much radiation is out there, waiting for us between Earth and Mars, but we’re not sure how the human body is going to react to it.”
For 45 years, NASA astronauts have been in Space, involving a few quick trips to the moon but otherwise, they have not spent much time far from Earth. Deep space is filled with protons from solar flares, gamma rays from newborn black holes and cosmic rays from exploding stars. There are no large planets nearby to deflect or block the radiation, making the trip to Mars very, very long.
NASA weighs radiation danger in units of cancer risk. A healthy 40 year-old-non-smoking American male stands a 20% chance of eventually dying from cancer. How, if he travels to Mars, the risk increases, how much is not known. There was a 2001 study of people who were exposed to large doses of radiation, included were Hiroshima atomic bomb survivors as well as cancer patients who had undergone radiation therapy. A 1000-day Mars mission has added a risk that lies between 1% and 19%. “The most likely answer is 3.4%” says Cucinotta, “but the error bars are wide. The odds are even worse for women he adds. “Because of breasts and ovaries, the risk of female astronauts is nearly double the risk to males.”
Assuming that the Mars-ship would be built largely of aluminum, the spaceship would absorb half the radiation hitting it. Aluminum is strong, lightweight and familiar to engineers after decades of use in the aerospace industry. Galactic cosmic rays—or “GSR’s” for short. Distant supernova explosions accelerate particles to almost light speed. A full dose of these deep space GCR’s have seldom been experienced by astronauts. But traveling to Mars means astronauts will be “out there” for a year or more. What will cosmic rays do to people who are exposed for so long?
The mission of NASA’s new Space Radiation Laboratory (NSRL) is to find the answer. Cucinotta said “The goal is to reduce the uncertainty in our risk estimates to only a few percent by the year 2015. NASA can decide what kind of spaceship to build once the risks are known. Can people go to Mars? Many people believe it is possible. How much radiation can the human body handle? What kind of spaceship should be built? The work has already begun to find the answers to these questions.
This entry was posted on Tuesday, February 12th, 2008 at 11:23 pm and is filed under Mission History. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.
