It is no surprise that astronauts undergo rigorous, lengthy training to do their jobs. They join the Astronaut Corps, usually as pilots or mission specialists, but then what? When do they go into space? How much time do they spend in space?
The truth is, an astronaut's time is spent in far more training and preparing to go into space than is actually spent in space. An astronaut's time is largely spent in the simulator and in other training arenas, if they are slated for the upcoming mission.
Before the U.S. retired the Space Shuttle, those vehicles were the only means the U.S. had of launching humans into space, so an astronaut’s time in space depended on how often the Shuttle launched and what missions it was slated to perform. Did it dock with the International Space Station or was it primarily a science mission? All these factors helped decide which astronauts were slated to fly on which missions.
When the U.S. resumes regular manned space flight, astronaut pilots, for example, will probably go on one or two missions to train as co-pilots before they are named the pilot of a spacecraft. Pilots are also selected depending on how much flight experience they have had, whether they have been test pilots, and how much time they’ve already spent in space.
An astronaut's time is spent between missions preparing for the next one. They work in large dive tanks that mimic weightless conditions, in order to learn how to perform spacewalks. Spacewalks were often used for repair missions on the International Space Station, the Hubble Telescope or on the Space Shuttle itself.
During the Shuttle years, a pilot astronaut's time was spent in intensive training involving flying modified business aircraft that mimicked the Shuttle's flying characteristics. The orbiter approached the runway at a steep angle and at over 300 miles per hour (483 kilometers per hour), so pilots needed to learn how to land an orbiter whose characteristics are so different even from a jet fighter.
Because of the limited number of Shuttle missions, much of an astronaut's time was spent on the ground. Some NASA analysts estimated the average wait time between qualification and the first space mission was 105 months. With the Space Shuttle program now retired, this time will stretch into a much longer wait, unless NASA decides to pare down the Astronaut Corps and not train more candidates until the agency has a more regular mission schedule in place.