Andie (Kate Capshaw) and her team of young SpaceCamp students get the opportunity to sit in the space shuttle during a routine engine test but are sent into space after Jinx, the loveable robot, initiates a sequence for a launch. Because the shuttle wasn't flight ready, the team has no radio contact with NASA and quickly runs out of oxygen. They head for the Dataless space station where Andie attempts to retrieve additional oxygen for them. However, the way the tanks are positioned, she cannot reach them and Max (a very young Joaquin Phoenix) saves the day by being small enough to retrieve them. But when Andie tries to hook up the second oxygen tank to the shuttle, an accident occurs and she is injured and almost floats out into space. The team saves Andie from death but misses their window to return to Earth.
With Andie unconscious, the team figures out a way to get home. Tish uses Morse code to contact Nasa, Rudy comes up with an alternate landing site at White Sands and Catherine (Lea Thompson) pilots the shuttle safely home.