STS-133: Discovery’s ET/SRB mate June 15 – ROMS back in July

by Chris Bergin

Currently the next mission scheduled to fly, Discovery’s processing for STS-133 is continuing minus her Right Hand Orbital Maneuvering System (ROMS) Pod, as it undergoes repairs in the Hypergolic Maintenance Facility (HMF) – prior to its reunion with the orbiter early in July. Meanwhile, External Tank (ET-138) will be mated with the twin Solid Rocket Boosters (SRBs) on June 15.

STS-133 Processing Latest:

Amid launch date and flight order evaluations, Discovery is currently processing for a September mission to the International Space Station (ISS) – although managers are all-but certain to change the launch date of the next mission to the end of October.

Although there remains the possibility that STS-133 will be placed back behind STS-134 – as originally planned – all processing targets continue to be for Discovery’s mission flying next.

“The next two, possibly three flights are still in discussion. Shuttle is on track to come up with a decision at the end of this month,” noted Space Shuttle Program (SSP) manager John Shannon on the latest Shuttle Standup/Integration report (L2).

“The discussions on AMS (Alpha Magnetic Spectrometer) are becoming clearer. They have the permanent magnetic installed and are reintegrating the payload.

“The cargo hardware development for STS-133 is going well. Whether STS-335 is flown as a LON (Launch On Need STS-335) or the hardware is kept back and used for something else down the road (STS-135) is still under discussion. Expect to have the remaining flights with clearly defined launch windows by the end of the month.”

STS-133 Specific Articles:

Progress is also being made on making the flight’s Change Request (CR) official, which would re-baseline STS-133 as a flight that includes two EVAs (spacewalks), extending the mission by three days.

“Put a CR in the system a few weeks back on duration and flight content on STS-133/ULF5 that is coming to the FOICB (Flight Operations Integration Control Board) this week,” noted Flight Operations & Integration. “It should go to the PRCB (Program Requirements Control Board) too.”

The main focus of Discovery’s flow relates to her ROMS, which is undergoing repair work at the HMF to replace the faulty helium isolation valve – which had failed open during the STS-131 pad flow, which – at the time of evaluations ahead of flight – threatened rollback and destacking for the work that is currently taking place.

Orbiter engineers at the Flight Readiness Review (FRR) allowed for the RRCS (Right Reaction Control System) valve to fly as-is, due to high redundancy in the system via downstream regulators, which proved to be a correct decision, as the system performed as advertised during the successful mission.

“Got the RH pod removed last Friday. Took it out to the HMF Monday morning,” noted Ground Operations, as the Pod rode past KSC office windows on the back of a truck, for its month long stay in the HMF. “Will start the repair, and the pod will be back in early July.”

Other work in the flow relates to the Power Reactant Storage and Distributation (PRSD) tank set 5, Orbiter Docking System (ODS) functional tests and Thermal Protection System (TPS) work around the ET doors.

“OV-103 (OPF Bay 3): PRSD H2 tank 5 removal is complete. The O2 tank 5 removal rescheduled for Monday,” noted processing information from the NASA Test Director (NTD) on L2. “LO2 shaft seal leak and decay checks were completed and good.”

Discovery’s 21st Interim Problem Report (IPR) was recorded on the O2 tank that is set to be removed, via an inadvertent overpressure of the system.

“New IPR 0021. PRSD O2 tank 5 inadvertently pressurized to 547 psia. No OMRS (Operational Maintenance Requirements and Specifications) violations however a tank cycle occurred when the pressure crossed 375 psia. Tank will be vented before it is removed as previously scheduled.

“Water Spray Boiler checkout and servicing began Tuesday and continues into next week. SCAPE (Self-Contained Atmospheric Protection Ensemble) operations supporting catch bottle drain were completed early this morning. S-band troubleshooting (IPR-0005) begins Thursday.”

Over in High Bay 3 of the Vehicle Assembly Building (VAB), work is continuing on the two stacked boosters on the Mobile Launch Platform (MLP), ahead of ET-137 joining the duo for mating on June 15. MLP 2 – which Atlantis launched from to begin STS-132 – also arrived at the VAB, ahead of booster stacking for STS-134 in High Bay 1.

“In the VAB, completed SRB stacking last week. Working preps for ET/SRB mate. Review on Friday. The tank mate will happen on June 15,” added Ground Operations. “The MLP #2 moved from the Pad to outside VAB HB-1 on Friday, and was brought inside the VAB on Monday.”

Most of the work on STS-133’s boosters relates to Cable Routing and Connections procedures, “ET Mate Preps; CAS installation and Stacking bridge removal are complete. Aft Restraint post installation next,” noted the NTD report.

For the ET over in High Bay 4E, engineers completed the plug pull tests that are continuing to check the adhesive properties on the intertank region, despite the root cause of the liberations found, along with the resulting mitigation procedures at the Michoud Assembly Facility (MAF) proving to be successful, with a vast reduction in the amount of shedding observed on recent flights (only one area on STS-132’s tank – see image).

Repairs to the test areas on the ET intertank, and the removal of scaffolding, is nearly complete, allowing for the tank to eventually head over to the boosters for mating next week.

“Bond Adhesive Test Repairs. PDL (foam) trim and sand, shore “A”, pre-scaffolding removal inspection and Final acceptance are all complete and no anomalies found. Scaffolding removal is next,” added processing information. “GUCP (Ground Umbilical Carrier Plate) Shroud Installation is complete. He Box closeout Final Inspections and TPS are complete.

“LO2/LH2 Umbilical Disconnect closeouts; Foam application, final trim and sand and final acceptance are complete.”

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