Some early technobabble...
MITCHELL: So, er, so, how go the repairs?
KELSO: Well, the main engines are gone, unless we can find some way to re-energize them.
MITCHELL: You'd better check the starboard impulse packs. Those points have about decayed to lead.
KELSO: Oh, yeah, sure, Mitch.
MITCHELL: I'm not joking, Lee!
You activate those packs, and you'll blow the whole impulse deck.