PERFORMANCE OF THE STAR TRACKER LIGHT SHADES ON THE EARTH OBSERVING SATELLITE (EOS) AQUA

摘要

The TRW-built EOS Aqua spacecraft uses two Ball Aerospace CT-602 star trackers to provide attitude updates to the 3-axis, zero momentum, and controller. Two months prior to the scheduled launch of Aqua, Ball Aerospace reported an error in the model of the star tracker light shades. The light shades, which had been designed specifically for the EOS Common spacecraft, were not expected to meet the stray light rejection requirements of the mission, thus impacting the overall spacecraft pointing performance. What ensued was an effort to characterize the actual performance of the existing light shade design, determine what could be done within the physical envelope available, and incorporate changes to meet requirements. Changes were made based on this review activity and Aqua was successfully launched on May 4, 2002. The spacecraft is meeting all of its science pointing requirements. Reported here are the light shade design predictions, the solution trade space, and the measured on-orbit performance of these light shades.