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Restoring Redundancy to the MAP Propulsion SystemThe Microwave Anisotropy Probe is a follow-on to the Differential Microwave Radiometer instrument on the Cosmic Background Explorer. Sixteen months before launch, it was discovered that from the time of the critical design review, configuration changes had resulted in a significant migration of the spacecraft's center of mass. As a result, the spacecraft no longer had a viable backup control mode in the event of a failure of the negative pitch axis thruster. Potential solutions to this problem were identified, such as adding thruster plume shields to redirect thruster torque, adding mass to, or removing it from, the spacecraft, adding an additional thruster, moving thrusters, bending thrusters (either nozzles or propellant tubing), or accepting the loss of redundancy for the thruster. The impacts of each solution, including effects on the mass, cost, and fuel budgets, as well as schedule, were considered, and it was decided to bend the thruster propellant tubing of the two roll control thrusters, allowing that pair to be used for back-up control in the negative pitch axis. This paper discusses the problem and the potential solutions, and documents the hardware and software changes that needed to be made to implement the chosen solution. Flight data is presented to show the propulsion system on-orbit performance.
Document ID
20020085345
Acquisition Source
Goddard Space Flight Center
Document Type
Preprint (Draft being sent to journal)
Authors
ODonnell, James R., Jr. (NASA Goddard Space Flight Center Greenbelt, MD United States)
Davis, Gary T. (NASA Goddard Space Flight Center Greenbelt, MD United States)
Ward, David K. (NASA Goddard Space Flight Center Greenbelt, MD United States)
Bauer, F.
Date Acquired
September 7, 2013
Publication Date
May 2, 2002
Subject Category
Spacecraft Propulsion And Power
Meeting Information
Meeting: AIAA Guidance, Navigation and Control Conference
Location: Monterey, CA
Country: United States
Start Date: August 6, 2002
End Date: August 10, 2002
Sponsors: American Inst. of Aeronautics and Astronautics
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.

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