NasaReport - April 13, 2007 Mars Global Surveyor (MGS)...

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April 13, 2007 April 13, 2007 Page 1 of 3 Mars Global Surveyor (MGS) Spacecraft Loss of Contact This is a preliminary report by the Mars Global Surveyor Operations Review Board, an internal NASA board formed to look into why MGS went silent in November 2006 and to recommend processes or procedures that could increase safety for other spacecraft. Summary NASA’s Mars Global Surveyor operated for ten years, longer than any other spacecraft sent to Mars. It pioneered the use of aerobraking, provided global mapping of the Martian surface, atmosphere, magnetic field and interior, and provided key imaging and communications support for subsequent missions. NASA extended its mission four times before its unfortunate loss. Key events pertaining to the loss of the spacecraft, whose last contact was on November 2, 2006, include: A modification to a spacecraft parameter, intended to update the High Gain Antenna’s (HGA) pointing direction used for contingency operations, was mistakenly written to the incorrect spacecraft memory address in June 2006. The incorrect memory load resulted in the following unintended actions: – Disabled the solar array positioning limits. -- Corrupted the HGA’s pointing direction used during contingency operations. A command sent to MGS on November 2, 2006 caused the solar array to attempt to exceed its hardware constraint, which led the onboard fault protection system to place the spacecraft in a somewhat unusual contingency orientation. The spacecraft contingency orientation with respect to the sun caused one of the batteries to overheat. The spacecraft’s power management software misinterpreted the battery over temperature as a battery overcharge and terminated its charge current. ! The spacecraft could not sufficiently recharge the remaining battery to support the electrical loads on a continuing basis. Spacecraft signals and all functions were determined to be lost within five to six orbits (ten- twelve hours) preventing further attempts to correct the situation. Due to loss of power, the spacecraft is assumed to be lost and all recovery operations ceased on January 28, 2007. Incident Description
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This document was uploaded on 11/03/2011 for the course CSE 442 at SUNY Buffalo.

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NasaReport - April 13, 2007 Mars Global Surveyor (MGS)...

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