Moon Zero Two (1969)

Factual error: Bill Kempt rigs the sapphire asteroid with rocket motors to divert it toward the Moon. The motors are old and cranky, and to ensure that they fire on time he must, at some risk, lash himself to the rock and manually start the ignition. Upon lighting the engines he has several seconds to cut himself free, but in the scene he's shown swinging weightlessly as he snips the cable. If the asteroid is accelerating, he ought not to be weightless, but rather should be hanging behind the rock on his tether.

Clem: All space travel is just a big way of getting out of the house on a Saturday evening.
Kemp: Well, if you don't have anything better to do.