Capricorn One by Ron Goulart

To all appearances the launching of Capricorn One, the first spaceship to Mars, seemed perfectly normal. Everybody in the country was watching the countdown on television.

But behind the scenes, two and a half hours before lift-off, a strange and terrifying drama was being played out. A NASA director was warning the three astronauts that their spacecraft was faulty. He told them they must fake the trip via computer magic. This way they could convince the President the mission had succeeded. Failure would mean the end of the space program.

Nothing would stop these madmen. Not the truth. Not reality. Especially not the astronauts, who become unwilling conspirators. For them, a special fate had been arranged...