I'm trying to identify a Disney TV movie from the late-80s to mid-90s. The plot points that I can remember are:
- 3 teenagers on a spacecraft, all in recently in trouble at their (military?) academy so being sent somewhere
- the ship malfunctions
- no adults around, period
- they meet some alien woman who agrees to help them because she "thought they were much older warriors" rather than kids
- the kids somehow have mechs (they look exactly like the Battlech Timber Wolf/Mad Cat mech)
- harvesting ice on a planet for water, they encounter some gigantic worm creature that can sense heat