NASA’s Hubble Space Telescope

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...

Hubble Space Telescope Rate Gyro Assemblies

Hubble has a sophisticated system that controls its position 24 hours a day. It is called the Pointing Control System (PCS). The PCS is composed of gyroscopes, reaction wheels, and fine guidance sensors.