Surviving Space: Risks to Humans on the Moon and Mars

There is no “biggest danger” in setting up a permanent lunar presence or sending people to Mars, says John Charles, an enthusiastic proponent of both ideas and a NASA analyst of the costs and risks of human space flight: “There are several.” Launch, landing and re-entry are perhaps the riskiest moments of any space venture, history shows. But on long missions, what would otherwise be minor threats could become at best serious limitations or at worst deadly disasters.