​​​NASA selects astronauts who begin their formal training program during the first year of selection by reading training manual and by taking computer-based lessons on the various vehicle systems. The next step in the training process involves the spacecraft systems. The astronauts are trained to o​perate each system, to recognize malfunctions, and to perform corrective actions if needed. "The biggest challenge to be astronaut is your ability to know a lot about a lot of things."    ​​​​​