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The radar failed self-test with a "333.3" signature as it had several times earlier in the mission.  The MCC reported that the failure was caused by unexplained noise and that there was no degradation in the radar.  One curiosity was noticed on the REL NAV display at the conclusion of the self-test.  REL NAV had interpreted the self-test as data and computed the residuals based on a range and range ration of "333.3."  This phenomenon had not been observed in any simulation and care was taken not to allow the data in the filter.

On each rendezvous the radar initially began tracking at about 114 kft broke track, and reacquired at about 114 kft.  The initial range residual was 1.8 kft on day 3 and -0.6 kft on day 5.  The radar track was solid in range, range rate, and angles.  At the MCC's suggestion, radar angles were selected instead of the third star tracker pass on both day 3 and day 5.

Throughout training and during each rendezvous the down range position of the Transition Initiate Maneuver (TI) was observed to increase from the nominal -48 kft target to as far as -58 kft on day 3.  The resulting trajectory on day 3 was greater than three sigma long.  Typically, the nominal corrective combination (NCC) burn would be trimmed to within 0.2 fps in each axis and a preliminary targeting of TI would confirm that the burn had hit the -48 kft target within 1 kft.  As the intermediate and final solutions were computed with little or no radar updates to nav, the trajectory would gradually become longer.  The day 5 trajectory was at -52 kft, between one and two sigma long.  This phenomenon of the range to the target increasing as compared to the predicted range seemed to continue after TI.  The first two midcourse burns on both day 3 and day 5 were 1 to 2 fps radially toward the earth, indicating that the range to the target was greater that the range predicted immediately after the preceding burn.  In each case, the TIG slip of the elevation burn MC2 was near or slightly beyond the 5-minute limit.

The final two midcourse burns were small on both day 3 and day 5, and the trajectory was nominal from sunrise through the manual trajectory control phase.  No pointing errors were evident at sunrise and an inertial attitude was established at the nominal time of MC2 + 22:00.  Very few THC inputs were required to maintain the inertial line-of-sight.  At 2000 feet the range rate was about 7.5 fps and the initial braking was done to reduce it to 4 fps.  At 1500 feet some additional braking was required to meet the 2 fps gate.  On day 3, the closure stopped 800 feet and the V-BAR was established before orbital noon.  On day 5, the closure rate was maintained to conserve FRCS propellant.  This resulted in reaching the V-BAR at 350 feet.  This type of approach is recommended for future rendezvous (R).

The backup techniques for determining range and range rate during the manual trajectory control phase required the use of overlays on a CCTV monitor.  This technique would not have been usable because of the inability of the CCTV's ALC loop to regulate on a small brightly-lighted target against a black background.  Manual control of the iris may have helped if time had permitted.  Ranging by measuring the subtended angle of the target in the COAS is probably adequate for trajectories that are not badly dispersed.