From Deep Impact
[about the Wolf comet
] Now the outgassing has created a vent a half mile wide and at least two miles deep. Comet gets closer to the sun; sun melts the ice, ice turns to steam. We get a big hole, okay? So, how many nukes do we have left in the back?
Okay. If we can get the remaining bombs in that vent, there shouldn't be anything left of that comet bigger than a suitcase. Now, we can't do anything about the little one, but you know... it just might give them a chance. Now, without the arming codes, we're going to have to wait to set the bomb timers until we get closer to Earth, to raise Houston.