TED: Geckos Utilize Nanotech

Engineer: These tails seem important.
Biologist: O rly?
Engineer: Ya rly!
Biologist: No wai! ...Oh wait... yes, you are correct; I'm astonished we never noticed.

This has bothered me before: why do spacecraft have thrusters for maneuverability? Couldn't there be some sort of a mechanical solution which doesn't require a physical fuel taking up valuable space? Seems like a tail on the back of the spacecraft might work, or perhaps a more elegant system of internal weights on a gyroscope.

JetSetArnett Out.

Like a streak of light he arrives just in time.