NASA is training for the first manned mission to Mars by the spacecraft ''Aries''. Due to a supposed glitch in the computer navigation system, NASA looks for the original programmer of the software to understand why it seems to be broken. Fred Z. Randall (Harland Williams), the programmer who wrote the software, meets Paul Wick (Jeffrey DeMunn), the flight director of the Mars mission; William "Wild Bill" Overbeck (William Sadler (actor)), the commander of the Mars mission; and astronaut Gary Hackman (Peter Onorati), the computer specialist. After a display of hard-headed stubbornness by Gary, he is hit in the head by a model of the ''Pilgrim 1'' Mars lander, resulting in a skull fracture. NASA decides to replace him instead of delaying the mission. Fred is brought to NASA to see if he has what it takes to be an astronaut; he, along with Gordon Peacock, go through a series of exercises, which sees Fred do well, even going as far to break every record that Bill had. In the end, Fred gets the job.