Introduction
Introduction
Thirty years after President John F. Kennedy proposed that the United States land a man on the moon within a decade, the Bush administration is pressing for several new manned space projects. Chief among them is a mission to Mars by the year 2019, the 50th anniversary of the first lunar landing. In contrast to the early 1960s, however, the new space proposals are meeting with considerable resistance. Not only do many experts question whether manned missions are worth their great cost, but memories of the 1986 explosion of the space shuttle Challenger still cast doubt on the safety of manned space flight in general.