STS-133: Discovery arrives at Pad 39A – ET-122 to ship on Tuesday

by Chris Bergin

In what is highly likely to be her final rollout, Discovery – as the STS-133 stack – departed from the Vehicle Assembly Building (VAB) Monday evening (7:23pm local time), before making good time for an arrival at Pad 39A, just after 1:15am. Meanwhile, the final External Tank (ET-122) – sporting its numerous repair patches – has been rolled into its Pegasus Barge, ahead of shipping to Florida on Tuesday.

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Despite a couple of challenging issues during Discovery’s VAB flow, speedy resolutions enabled the stack to remain on schedule for Monday’s rollout. Platforms were retracted prior to an off-weekend for her team, with final walkdowns completed during Monday morning.

“OV-103 / SRB BI-144 / RSRM 112 / ET-137 (VAB HB-3): A5214 Shuttle Transfer and mate to Pad A: VAB platform retracts are complete. Final walk-downs and inspections were performed today,” noted the NASA Test Director (NTD) processing report (L2).

“CTS (Call To Stations) is planned for 16:00 today, with first motion to Pad A expected at 20:00.” UPDATE: Discovery’s first motion was ahead of schedule, at 7:23pm local.

The schedule remained on track thanks to the resolution of a Problem Report (PR) charged against a damaged bolt on the T-0 umbilical, associated with the left hand Tail Service Mask (TSM) carrier plate.

The issue was cleared after engineers drilled through the bolt, allowing for its removal, ahead of the installation of a a temporary replacement. Additional work on the T-0 bolt, in order to configure the vehicle for launch, will take place during Discovery’s pad flow.

“PR 9986, LH (Left Hand) lower T-0 umbilical bolt damage: A temporary bolt, nut, and washer was installed Friday evening to configure the T-0 for rollout,” added the NTD report. “Any additional work required will be performed at the pad. Platforms that access this area have been dropped.”

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A leak out at the pad – relating to one of the GH2 racks at 39A’s GH2 farm – was also cleared from being a constraint to rollout.

“Pad-A: A leak was detected on one of the three GH2 Racks in the Pad A GH2 Farm. On Friday, GH2 in the rack was burned off, the rack was inerted, and a nose seal was repaired. The rack was pressurized to 500 and verified there were no leaks. Sampling will occur today and GH2 recharging will pickup once good samples are verified,” noted the NTD report.

“Engineering analysis of Pad using ground penetrating radar has been completed. There are no concerns and no operational constraints levied against pad operations.”

After arriving at the pad, in what appears to be one of the fastest rollouts seen in recent years, Discovery is now moving into pad validation work, which includes mating the Ground Umbilical Carrier Plate (GUCP) to the External Tank in the early hours of Tuesday, and the Rotating Service Structure (RSS) being translated into the mate position on Tuesday evening.

“S0009 Launch Pad Validation: CTS is planned for 02:30 Tuesday morning. OAA (Orbiter Access Arm) extend, GVA (GOX Vent Arm) align, ET/IT (Intertank) Access Arm extend, and GUCP mate will all be performed once the vehicle is hard down at the pad Tuesday morning,” the NTD added.

“RSS rotation to the mate position is planned for 21:30 Tuesday.”

Live updates and coverage are being provided on the STS-133 forum section.

ET-122 Ready To Ship:

ET-122 has been loaded on to the Pegasus Barge at the Michoud Assembly Facility (MAF) in New Orleans, ahead of setting sail for a several day journey to the Kennedy Space Center (KSC). This is the last tank to be shipping from MAF under the current Space Shuttle Program (SSP) manifest.

The tank sports a number of repair patches on its LOX tank, which were required after the tank sustained damage during Hurricane Katrina in 2005.

During the hurricane, the roof of the building that housed the tank was ripped off by high winds. After falling debris damaged the tank, it was removed from the shuttle flight manifest. Lockheed Martin engineers assessed the damage, and prepared and executed a tank restoration plan.

“Hurricane Katrina damaged ET-122 in Cell A when concrete fell from the roof and hit some areas of the tank,” noted Lockheed Martin’s ET Program Manager Wanda Sigur in 2008. “We’ve been asked to put together a proposal about ET-122 to determine how and when the tank could be returned to the fleet for NASA to evaluate.

“We are working on that. ET-122 could be used possibly as a launch-on-need tank or for other NASA objectives in the future.”

ET-122 – partnered with Atlantis – was assigned as the LON (Launch On Need) support of STS-134, under the designation “STS-135, LON Support for STS-134”. However, pre-empting the conclusion of the on-going political process, relating to the funding of STS-135, managers hold the option of switching ET-122 to STS-134, allowing the newer ET-138 to fly with STS-135.

This was confirmed by a recent Program Requirements Control Board (PRCB) meeting, which opted to delay the tank allocation decision until the latest possible point in the schedule – currently mid November.

“When ET-122 arrives at KSC it will be lifted into the VAB HB-4 (High Bay 4) Checkout cell for processing since ET-138 currently is occupying the HB-2 Checkout Cell,” noted KSC managers on the PRCB presentation (L2).

“The STS-134 SRB stack is currently located in HB-1 and will have to be ‘rolled around’ to HB-3 after STS-133 rolls out to the pad in order to support and ET-122/BI-145 (STS-134) ET/SRB mate.

“Response: Putting ET-122 on STS-134 will result in ET mate moving to Nov 18th, to support VAB OPS for the 18th, KSC final tank decision date is Nov 10th.”

ET-122 is expected to arrive at KSC on Sunday, September 26.

(Lead Photograph: Larry Sullivan, and MaxQ Entertainment)

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