Mar
13
2010
RSS rollback, payload to the pad delayed at least 24 hours
Posted by STS 131 Mission Updates in Shuttle Update
Last night, while venting shuttle Discovery's aft fuel propellant tanks in preparation for fuel loading, the Right Reaction Control System (RRCS) fuel helium tank pressure unexpectedly decreased in unison with the RRCS fuel propellant tank.
Troubleshooting overnight revealed at least one helium isolation valve that is leaking or is remaining in the open position when it is expected to be closed.
Following a review meeting this morning, engineers have decided to complete Orbital Maneuvering System (OMS) Reaction Control System fuel loading, Solid Rocket Booster Hydraulic Power Unit (HPU) tilt system and Auxiliary Power Unit (APU) hydrazine loads this weekend.
Engineers will meet again Monday morning to discuss options.
Currently, Rotating Service Structure (RSS) rotation will be delayed to no earlier than Tuesday, March 16; and payload delivery to the pad will be delayed to no earlier than Wednesday, March 17.
Launch still is targeted for April 5.
Troubleshooting overnight revealed at least one helium isolation valve that is leaking or is remaining in the open position when it is expected to be closed.
Following a review meeting this morning, engineers have decided to complete Orbital Maneuvering System (OMS) Reaction Control System fuel loading, Solid Rocket Booster Hydraulic Power Unit (HPU) tilt system and Auxiliary Power Unit (APU) hydrazine loads this weekend.
Engineers will meet again Monday morning to discuss options.
Currently, Rotating Service Structure (RSS) rotation will be delayed to no earlier than Tuesday, March 16; and payload delivery to the pad will be delayed to no earlier than Wednesday, March 17.
Launch still is targeted for April 5.
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