|MadSci Network: Engineering|
Protection of astronauts from radiation in space is a major concern, especially for long duration flights. However, the amount of radiation in a normal mission is not as extensive as some people believe. In many cases the dose is similar to what you would receive during an airline flight at 35,000 feet (approximately 11,000 meters). Within the space shuttle or Mir space station, the metal of the hull and the various instruments mounted on the walls make a reasonably good shield against soft X-rays and similar radiation. The NASA's Space Radiation Analysis Group has information regarding this question. Also, the duration of the flights are sufficiently short that there is little danger of receiving a massive dose. Both the shuttle astronauts and Mir cosmonauts have the ability to abort their mission and return to Earth in about one hour if a life threatening solar flare occurred.
That is not to say that there is no danger from radiation. For longer flights to Mars or extended stays on the Moon, radiation will be a major concern. Not because of the amount the astronauts receive per day, but because of the cumulative nature of radiation damage and the long time spent on the mission. Here simple materials will be most commonly used. On the Moon, the simplest thing to do is bury everything. A couple of feet of the Moon's soil on top of a structure will effectively stop all radiation during the lunar day. During the lunar night, the Moon itself will block most of the radiation. For a Mars mission, there are plans to have a lead shielded section of the craft. While it would not normally be needed, during major solar flares and other solar events that release radiation, the crew would retreat to this chamber for the duration of the flare, typically a few hours to a couple of days.
More advanced materials may evolve or be discovered, but there probably will not be any major changes in the next several years.
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