Universe  ID: 13421

Hubble Archive - Servicing Mission 3A, STS-103

Hubble's third servicing mission, Servicing Mission 3A, launched on December 19, 1999 on Space Shuttle Discovery as part of the STS-103 mission.

What was originally conceived as a mission of preventive maintenance turned more urgent on November 13, 1999, when the fourth of six gyros failed and Hubble temporarily closed its eyes on the universe. Unable to conduct science without three working gyros, Hubble entered a state of dormancy called safe mode. Essentially, Hubble "went to sleep" while it waited for help.

NASA decided to split the Third Servicing Mission (SM3) into two parts, SM3A and SM3B, after the third of Hubble's six gyroscopes failed. In accordance with NASA's flight rules, a "call-up" mission was quickly approved and developed and executed in a record 7 months.

The Hubble team left the telescope far more fit and capable than ever before. The new, improved, and upgraded equipment included six fresh gyroscopes, six battery voltage/temperature improvement kits, a faster, more powerful, main computer, a next-generation solid state data recorder, a new transmitter, an enhanced fine guidance sensor, and new insulation.



Paul R. Morris (USRA): Lead Producer
Aaron E. Lepsch (ADNET Systems, Inc.): Technical Support
Please give credit for this item to:
NASA's Goddard Space Flight Center