Hubble Space Telescope pointing control system: Designed for performance and mission operations

The Hubble Space Telescope was designed to be an orbiting astronomical observatory which could be operated in the same manner as ground based observatories. The design drivers for the pointing control system's hardware and software were the requirements of an absolute pointing accuracy of 4.8E-8 radians and pointing stability (jitter) of 3.4E-8 radians. Of comparable importance was the objective of providing a flexible command methodology and structure to enable seven day operational planning employing stored program command and real time command capability. The pointing control system hardware, software, safemode control schemes, ground system monitoring capability, and in-orbit results are reviewed.