Hubble Space Telescope Rate Gyro Assemblies

NASA's Hubble Space Telescope

Backdropped by the horizon of the blue and white Earth and the blackness of space, the Hubble Space Telescope floats gracefully after the release from Columbia's robot arm at the close of a successful servicing mission in March of 2002.

HST Pointing Control System Diagram

Hubble uses some very basic physics to turn itself around and look at different parts of the sky. Located on the telescope are six gyroscopes (which, like a compass, always point in the same direction) and four free-spinning steering devices called reaction wheels. The...