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10 The release and separation were nominal in all respects. The END EFFECTOR mode was entered and the Orbiter was placed in free drift about 2 minutes before the release. The first few inches of RMS motion after the release were done with vernier rates and a minimum THC input. During the 3 minutes following the release, no relative motion was observed using the trunnion pin overlay on the CCTV monitor. The 0.5 fps posigrade separation rate was verified by radar at about 100 feet and the laser range finders tracked to about 200 feet. The REL NAV function was used with the radar as its input. At about 300 feet several radar angles were rejected with a residual of about 4 degrees. It seemed that the likely cause at this close range was a shift of the tracking from one point of the LDEF to another as the aspect angle changed. At about 1200 feet the Ku mode was changed to a general purpose computer (GPC). The radar broke track momentarily and then reacquired with angle residual of about 7 degrees. The angles were rejected until auto track was reestablished at about 1800 feet. The bad angle data appeared to have been caused by a sidelobe tracking the target. Radar tracking was discontinued after 2800 feet. At 25,000 feet, radar acquisition in GPC was attempted with the Orbiter in -ZLV nose forward. Target track was immediate and the REL NAV performed nominally until the radar track was discontinued at about 35,000 feet. RENDEZVOUS The onboard rendezvous phase began on day 3, 1 hour before the nominal height (NH) burn, and ended at the velocity vector axis (V-BAR) stationkeeping with the initiation of proximity operations. A second rendezvous on day 5 was completed using similar procedures without the need for an NH burn. In order to conserve propellant on day 5 all of the attitude maneuvers were done in vernier reaction control system (VRCS) at the 0.2 degrees per second, instead of the nominal 0.5 on PRCS. The first star tracker pass began at about orbital noon three orbitals before the rendezvous. The -Z star tracker initially began tracking a star that was several degrees from the predicted line-of-sight to the target. A BREAK TRACK was commanded and the target was acquired on the next attempt. The initial residuals were small but were randomly changing by more than the .05 degree limit per navigation (nav) cycle. AUTO editing was selected since the residuals seemed to be centered on the target. The FILTER MINUS PROP (F-P) parameter varied between 1 kft and 4 kft in response to the noisy data and the star tracker pass ended with 173 marks and a F-P of 1 kft. The target was barely visible 10 minutes after orbital noon and could be marked with the crew optical alignment sight (COAS) at 20 minutes. The range was approximately 600 kft. The second start tracker pass occurred at about 250 kft and had similarly noisy data at times. It ended with 152 marks and a F-P of 5 kft. By contrast, the -Z star tracker showed no noise during either pass of the day 5 rendezvous. With 155 marks on the first pass and 101 on the second, the day 5 F-P's were 2 kft and 1 kft. The only day 5 star-tracker anomaly occured when a piece of ice, visible in the COAS, caused the star tracker to temporarily break track with the target. The angles were rejected for two nav cycles and the target was automatically reacquired.
