Hubble Engineering

Astronauts, with the assistance of Hubble engineers, practice the replacement of a Rate Sensor Unit, a device that holds two gyroscopes, that are part of Hubble's pointing control system. Here they are seen replacing a unit in the High Fidelity Mechanical Simulator, a replica of Hubble's aft shroud, in a clean room at NASA's Goddard Space Flight Center. The Rate Sensor Unit, astronaut tool, and simulator were all engineered for the missions.