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It could have been a pilot or a tv movie. I think it aired on broadcast tv mid to late 90s. The main plot point I remember (It has been a while so some may be a bit off):
- Starts with Military Ball, Jr officer approaches Lady, who turns out to be his commanding officer.
- All hands on deck, heading to space battle far away.
- All humans (no aliens).
- Ship breaks down en-route to battle.
- Engineer goes inside giant horizontal cylinder engine cavity.
- One of the crew turns on the engine. Engineer gets fried.
- Space Trial! Vote by dropping black or white marble into a vase.
- One lady is not shy about which marble goes in the vase.
- All black marbles, saboteur dumped out the airlock.
- Engine fixed, head back to giant space battle.