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Compton Gamma Ray Observatory: Lessons Learned in PropulsionThe Compton Gamma Ray Observatory was the second of NASA's Great Observatories. At 17 1/2 tons. it was the heaviest astrophysical payload ever flown at the time of its launch on April 5, 1991 aboard the Space Shuttle. During initial, on-orbit priming of the spacecraft's monopropellant hydrazine propulsion system, a severe waterhammer transient was experienced. At that time, anomalous telemetry readings were received from on-board propulsion system instrumentation. This led to ground analyses and laboratory investigations as to the root cause of the waterhammer, potential damage to system integrity and functionality, and risks for switching from the primary (A-side) propulsion system to the redundant (B-side) system. The switchover to B-side was ultimately performed successfully and the spacecraft completed its basic and extended missions in this configuration. Nine years later, following a critical control gyroscope failure, Compton was safely deorbited and re-entered the Earth's atmosphere on June 4, 2000. Additional risk assessments concerning viability of A- and B-sides were necessary to provide confidence in attitude and delta-V authority and reliability to manage the precisely controlled reentry. This paper summarizes the design and operation of the propulsion system used on the spacecraft and provides "lessons learned" from the system engineering investigations into the propellant loading procedures, the initial priming anomaly, mission operations, and the commanded re-entry following the gyro failure.
Document ID
Document Type
Preprint (Draft being sent to journal)
Dressler, G. A. (TRW, Inc. Redondo Beach, CA United States)
Joseph, G. W. (TRW, Inc. Redondo Beach, CA United States)
Behrens, H. W. (TRW, Inc. Redondo Beach, CA United States)
Asato, D. I. (NASA Goddard Space Flight Center Greenbelt, MD United States)
Carlson, R. A. (City of Rancho Palos Verdes Palos Verdes, CA United States)
Bauer, Frank H.
Date Acquired
September 7, 2013
Publication Date
January 31, 2001
Subject Category
Spacecraft Design, Testing and Performance
Report/Patent Number
AIAA Paper 2001-3631
Meeting Information
37th AIAA/ASME/SAE/ASEE Joint Propulsion Conference and Exhibit(Salt Lake City, UT)
Distribution Limits
Work of the US Gov. Public Use Permitted.

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