The first human to go into space, Soviet cosmonaut Yuri Gagarin, made a one-orbit, ninety-minute flight around Earth on April 12, 1961. Up to mid-2001, only 407 additional humans (370 men and 37 women) have gone into orbit, some of them making multiple journeys into space. Most of these individuals were a mixture of career astronauts, trained either to pilot space vehicles or to carry out a changing variety of tasks in orbit, and payload specialists, who also went through extensive training in order to accompany their experiments into space. In addition, there were a few people who got the opportunity to go into space because of their jobs on Earth (e.g., U.S. politicians). Other individuals flew into space because their country or company had paid for access to space, thereby getting the right to name someone to participate in the spaceflight in exchange for that funding...