yee@trident.arc.nasa.gov (Peter E. Yee) (05/04/91)
MCC STATUS REPORT #15 5 a.m. May 3, 1991 The blue team aboard Discovery spent their sixth work shift in space working with the Far Ultraviolet experiment, making observations of the Earth, celestial targets, and a phenomenon known as "shuttle glow," caused by the interaction of atomic oxygen with the spacecraft. In Mission Control, flight controllers spent much of the night assessing tracking data from ground radar sites on the two CRO subsatellites deployed from Discovery during the past day and a half. Following those assessments, Discovery will perform a series of two engine firings to raise its orbit above that of the subsatellites and avoid any possiblity of reentering their vicinity during the remainder of the mission. To allow for the best possible tracking assessment, Discovery's altitude-gaining maneuvers were delayed several hours, and the deployment of a third CRO subsatellite was postponed until after the engine firings are completed. Better tracking information is important to determine the most fuel-efficient method of avoiding the deployed CRO subsatellites. Fuel economy is extremely important on this flight due to the mission's large number of engine firings and the overall length of the flight. The delay in deployment of the third CRO subsatellite has not affected plans to conduct a third gas release observation of that satellite later in the flight. Flight controllers now anticipate deploy of that third subsatellite at a mission elapsed time of 5/00:36 or around 7:10 a.m. CDT Friday. Also today, the crew of Discovery is scheduled to again unberth the Shuttle Pallet Satellite and Infrared Backgrond Signature Survey for a series of scientific observations to be conducted with the instrument while it is held on the end of Discovery's mechanical arm.