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An Anomalous Force on the Map SpacecraftThe Microwave Anisotropy Probe (MAP) orbits the second Earth-Sun libration point (L2)-about 1.5 million kilometers outside Earth's orbit-mapping cosmic microwave background radiation. To achieve orbit near L2 on a small fuel budget, the MAP spacecraft needed to swing past the Moon for a gravity assist. Timing the lunar swing-by required MAP to travel in three high-eccentricity phasing loops with critical maneuvers at a minimum of two, but nominally all three, of the perigee passes. On the approach to the first perigee maneuver, MAP telemetry showed a considerable change in system angular momentum that threatened to cause on-board Failure Detection and Correction (FDC) to abort the critical maneuver. Fortunately, the system momentum did not reach the FDC limit; however, the MAP team did develop a contingency strategy should a stronger anomaly occur before or during subsequent perigee maneuvers, Simultaneously, members of the MAP team developed and tested various hypotheses for the cause of the anomalous force. The final hypothesis was that water was outgassing from the thermal blanketing and freezing to the cold side of the solar shield. As radiation from Earth warmed the cold side of the spacecraft, the uneven sublimation of frozen water created a torque on the spacecraft.
Document ID
20020088666
Acquisition Source
Goddard Space Flight Center
Document Type
Preprint (Draft being sent to journal)
Authors
Starin, Scott R.
(NASA Goddard Space Flight Center Greenbelt, MD United States)
ODonnell, James R., Jr.
(NASA Goddard Space Flight Center Greenbelt, MD United States)
Ward, David K.
(NASA Goddard Space Flight Center Greenbelt, MD United States)
Wollack, Edward J.
(NASA Goddard Space Flight Center Greenbelt, MD United States)
Bay, P. Michael
(Jackson and Tull, Inc. Washington, DC United States)
Fink, Dale R.
(Computer Sciences Corp. Lanham, MD United States)
Bauer, Frank
Date Acquired
September 7, 2013
Publication Date
January 1, 2002
Subject Category
Spacecraft Design, Testing And Performance
Meeting Information
Meeting: AIAA GN and C Conference
Location: Monterey, CA
Country: United States
Start Date: August 5, 2002
End Date: August 8, 2002
Distribution Limits
Public
Copyright
Public Use Permitted.
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