AAS 97-618

MARS GLOBAL SURVEYOR: AEROBRAKING WITH A BROKEN WING

D.T. Lyons - Jet Propulsion Laboratory

Abstract

The Mars Global Surveyor spacecraft was launched successfully on November 7, 1996, on a Delta II 7925. During the initial spacecraft deployment, one of the two solar wings failed to deploy fully. Mars Global Surveyor will use an aerobraking phase much like that used to circularize the Magellan orbit. The solar wings supply most of the surface area that provides the drag that will result in a total V of more than 1200 m/s during the four-month aerobraking phase. Aerobraking moments might be as large as 500 in-lb at the unlatched hinge in the worst case situation. Since the 60 in-lb spring force was clearly not large enough to hold the panel in position for the planned aerobraking configuration, a new configuration had to be developed for the aerobraking phase. The paper will describe the redesigned aerobraking phase, which will begin on September 21, 1997.