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Because of operational simplicity and to save EVA consumables, it is recommended that EVA crewmembers remain on the service an cooling umbilicals (SCUs) unit ready to egress and leave the SCU oxygen ON during the EVA to facilitate ingress post-EVA (R).

MMU OPS: All MMU OPS were nominal.  As noted on STS 41-B, propellant usage was high during maneuvers with attitude hold engaged and while stationkeeping.  During the checkout flight, EVA 1 noted that the CG offsets were more similar to the "old" valves used int he space operations simulator (SOS) model than the "new" valves used for the last training run.  Both crewmen were impressed with the MMU flying characteristics.  It was very stable and maneuverable. The limb motion filter was tested by both crewmen and neither noted excessive jet firings. 

The thruster cue light extenders were used on EVA 1 but not on EVA 2.  They were helpful during the docking and stabilization attempts on the Solar Maximum Satellite, and should be used on operational flights (R).

MMU pre- and post- was nominal.  The tolerances were too tight on the arm retention straps.  They should be a least 1/4 inch longer (R).  Tightening the two top launch bolts manually was a tedious, time-consuming task.

Solar Maximum Satellite Docking Attempts:  The flyover to the Solar Maximum Satellite was nominal.  A small pitch rate was imparted to the Solar Maximum Satellite from the MMU plume prior to any contacts.  Three attempts were made to dock with the satellite at approximate rates of 0.1, 0.15 and >0.2 ft.sec,  All resulted in an elastic bounce off the trunnion pin at a comparable rate.  The first two attempts were done with attitude hold engaged in pitch and roll.  This resulted in a slight pitch down attitude on the second try, but still within the capture envelope of the Trunnion Pin Attachment Device )TPAD).  The third attempt was accomplished without attitude hold due to the rates already on the Solar Maximum Satellite.  Each docking attempt put a larger pitch rate into the Solar Maximum Satellite.

It was felt that a manual release capability of the TPAD would have allowed the MMU to dock with the Solar Maximum Satellite (R).  Even then the thermal blanket standoff pin could have kept the expanding bolt from engaging the threads in the trunnion pin.  One attempt was made to stabilize the Solar Maximum Satellite by holding onto a solar array and engaging MMU attitude hold in the satellite stabilization mode.  During this attempt, the rates were reduced to a Solar Maximum Satellite roll in the opposite direction from the original rotation.  After release from the solar array, the Solar Maximum Satellite roll rates coupled into the other two axes resulting in an unpredictable tumbling motion.

MMU Engineering Evaluation Flight:  During EVA 2, the MMU was flown within the payload bay.  The thruster cue light extenders were not available  and were not required for these tests.  To investigate the effects of CG offsets a series of maneuvers were flown without altitude hold.

     (1) + X Translation

       Chatter was not present.  The + pitch rate induced was very similar 
       to the last training run made in the SOS.