I'm trying to remember the title of a film in which a crew of very young people are embarked on a ship for a trip to a distant planet. There is almost no images of the planet until the end, when the youngest of them recovers a broken transmission. On their trip they get an older man (actually some sort of captain of a military ship) who helps them in a combat by crafting a cannon (they were sent unarmed). I remember two scenes that may be definitory:
In one scene one of the guys is weight training with just two small transparent pieces on his hands, whose weight is remotely adjusted.
In another scene, the "bad guy" on the crew (the one who actually liked computer games more than studying and who barely graduated) saves the ship from an asteroid field by driving the ship as if it were a videogame. EDIT: Not actually asteroids but debris.
Can somebody remember which film was this? It is most probably from the 80's.