LEA THOMPSON leads a listless cast of teenage astronauts in the slight new kids' adventure "SpaceCamp" -- not only is the food bad, but there's no gravity.

And no levity either as these outer space cadets, daffy trainees at a NASA prep school for the upwardly mobile, practice weightlessness and flying in a straight line. Kate Capshaw, an unnerving presence with her Christa McAuliffe hair style, costars as their instructor, an untested astronaut with fantasies of future lift-off.

In the end, everybody's stuff is tested when a training exercise misfires and the space campers take an unexpected shuttle voyage. The highly implausible plot finally gains momentum when the kids are lost in space, orbiting Earth with only a slim chance of coming home before the oxygen gives out. Mission Control is silent; Capshaw is out cold; and Thompson, an untested pilot, takes the stick like Karen Black in "Airport '75."

The script takes a swipe at sexual stereotypes, but only serves to reinforce them when the writers put Thompson in her place. "I'm a good pilot," she weeps on the shoulder of love interest Tate Donovan. "But I'm no commander." Donovan, a reluctant commander, finds that he is a born leader.

The only black crewman (Larry B. Scott), a slow learner whose goal is a McDonalds franchise in space, overcomes a confidence problem during the desperate climax. The women are either unconscious, crying or dithering incomprehensibly, with Kelly Preston particularly maddening as an idiotic Valley Girl who came to camp to meet extraterrestrials. Leaf Phoenix completes the cast as Max, a 10-year-old computer prodigy who befriends a robot named Jinx who starts all this nonsense in response to Max's whining in the first place.

Robots, the Force, John Williams' space Musak: "SpaceCamp" is derivative of every starstruck story of this decade. The only thing that distinguishes it is its eerie parallel to the Challenger disaster, which the movie predates. The producers, criticized for its release, say kids are resilient, adding that enrollments are up at the U.S. Space Camp on which the story is based. And in fact, "SpaceCamp's" happy ending may even reassure some kids, though many of the shuttle shots recall the fatal mission.