What if one of the greatest space adventures was really a hoax? The whole world is watching the first manned flight to Mars prepare. Suddenly, its astronauts (James Brolin, Sam Waterson and O.J. Simpson) are taken from the craft to an abandoned desert hanger where NASA's director (Hal Holbrook) tells them their life support systems have failed. Because the mission's success is crucial to future space programs, he orders them to take part in a simulated Martian landing as cameras roll. If they refuse, their families will be harmed.
The phoney flight goes well until an uniformed NASA technician spots a computer discrepancy. He mentions it to a reporter friend (Elliott Gould) who smells a story and starts to investigate. When their rocket disintegrates and the world thinks them dead, the astronauts realise their lives are in danger. They escape and separate - hoping one will survive to expose the sensational fraud.