National Academies, Managing Space Radiation Risk in the New Era of Space Exploration, Committee on the Evaluation of Radiation Shielding for Space Exploration, National Research Council, 2008.

“Summary Space exploration is a risky enterprise. Rockets launch astronauts at tremendous speeds into a harsh, unforgiving environment. Spacecraft must withstand the bitter cold of space and the blistering heat of reentry. The skin of these vehicles must be strong enough to keep the inside comfortably pressurized and tough enough to resist damage from micrometeoroids. Spacecraft meant for lunar or planetary landings must survive the jar of landing, tolerate dust, and be able to take off again. For astronauts, however, there is one danger in space that does not end when they step out of their spacecraft. The radiation that permeates space—unattenuated by Earth’s atmosphere and magnetosphere—can damage or kill cells within astronauts’ bodies, resulting in cancer or other health consequences years after a mission ends. The National Aeronautics and Space Administration (NASA) recently embarked on Project Constellation to implement the Vision for Space Exploration – a program announced by President George W. Bush in 2004 with the goal of returning humans to the Moon and eventually transporting them to Mars. To prepare adequately for the safety of these future space explorers, NASA’s Exploration Systems Mission Directorate requested that the Aeronautics and Space Engineering Board of the National Research Council establish a committee to evaluate the radiation shielding requirements for lunar missions and to recommend a strategic plan for developing the radiation mitigation capabilities needed to enable the planned lunar mission architecture.”