to help people get to space to help people get to space
bicycles, space shuttles, airplanes and yo-yos. there are lots of other uses too.
one example is the Hubble Space Telescope. it has six gyroscopes:three to stay on balance and three are spares
Yes, it uses 4.
A drawbridge allows welcome guests into a castle to cross the moat(a trench of water that goes around the perimiter of the castle)