I belive it’s a 90’s made for tv movie. A crew of cadets in training are attacked or have an accident and the command crew dies, leaving them alone in space. There are 2 factions on earth. One is kinda evil, and one good. The evil one is trying to take over one of the goods planets but there are people living on it, so they will kill off all the people on it and claim the planet as theirs. The cadets try to stop this and do. but there is also a mutiny on board and they have to space a fellow cadet.
About the ships they use, they have a gun on the bottom that opens up a hyper-space/tunnel by shooting a pulse (the gun looks like the hammerheads :space above and beyond weapon)
Any help will be appreciated.