STS-134: Hardware and planning aligning for Endeavour’s final mission

by Chris Bergin

Endeavour is deep into her processing flow for the STS-134 mission to the International Space Station (ISS), as engineers worked through a few hiccups with her AMS payload. Managers continue to work on the STS-134 mission baseline, which may include a fourth EVA. ET-122 is also now assigned to STS-134 in processing charts – pending the funding of STS-135.

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STS-134 is currently baselined as a 12+1+2 day flight with 3+1 EVAs (Spacewalks), with a total of six crewmembers – refined from its original baseline. The launch date continues to track February 26, 2011.

Among the multitude of payloads Endeavour will carry to orbit are the Alpha Magnetic Spectrometer 2 (AMS-02), Express Logistics Carrier 3 (ELC-3), Materials on International Space Station Experiment 8 (MISSE 8), an Orion Rendezvous Detailed Test Objective (DTO) kit, and a GLACIER freezer module for one of the Station’s science laboratories.

Endeavour will also return the MISSE 7a and 7b experiments to Earth, as well as perform four Department of Defense payloads of opportunity: MAUI, SEITI, RAMBO-2, and SIMPLEX.

Furthermore, Endeavour and her six person crew will also be tasked with two Development Test Objectives – or DTOs. These include DTO 805, Crosswind Landing Performance, and DTO 703, Sensor Test for Orion Relative-Navigation Risk Mitigation (STORRM).

Currently, Endeavour is set to leave the OBSS (Orbiter Boom Sensor System) on the ISS – although it is possible that task will be deferred to STS-135, should the additional mission receive the required funding.

As is routine, mission managers are continuing to evaluate options to refine Endeavour’s mission, with the latest notes pointing to the potential of adding a fourth EVA – related to the recent refinements that saw the swapping of STS-133’s EVA running order.

“The decision was made at the SSPCB (Space Station Program Control Board) to swap EVAs 1 and 2, and to do the first EVA prior to installing the PMM (on STS-133). This is for access for one of the tasks that was added,” noted a Mission Operations memo (L2). “They are still looking at impacts to STS-134 and looking at a potential fourth EVA.”

Endeavour is in a smooth flow, with only 18 Interim Problem Reports (IPRs) charged against her flow since returning from STS-130 – the latest of which related to problems with the recent Alpha Magnetic Spectrometer/Orbiter compatibility test.

“IPR-18: No Communication between AMS2 J-Crate and Laptop Computer at J59. Troubleshooting determined the problem was due to reference arrows associated with signal direction of the ‘XMIT’ and ‘RCV’ connectors at the laptop computer,” noted several NASA Test Director (NTD) report (L2). “The cables were correctly configured and testing continued.

“Alpha Magnetic Spectrometer/Orbiter compatibility test ran into a few issues. The team suspects a GSE (Ground Support Equipment) issue. The payload community is attempting to resolve the issue. Testing (also) experienced another problem with the laptop computer during the playback phase of the test. This will require some analysis and further testing.”

However, by the end of last week, the testing was completed with no further issues, as engineers continued nominal processing tasks inside Endeavour’s Orbiter Processing Facility (OPF-2) – bar the interruption of the broken water main, which shut KSC down for a couple of shifts late last week.

“OV-105 (STS-134) In the OPF, the AMS compatibility test is now complete and good,” noted Ground Operations (L2). “Both the flipper door closeouts and the SSME (Space Shuttle Main Engines) carrier panel installation work continues.”

Ammonia servicing QD (Quick Disconnect) connects and leak checks were successfully completed, ahead of sampling, which noted a leak on one of the GSE’s valves. However, the valve in question was not critical to the operation, allowing for the completion of the task, and the transition into NH3 system fill and sampling.

“Ammonia (NH3) servicing GSE fill and sampling was initiated Friday afternoon. GSE IPR-1161 was taken for an undetermined loss of ammonia following the GSE system fill. A GSE valve was found to be leaking internally,” the NTD added on Monday.

“The valve was removed and the lines capped off since it was not required for this operation. The GSE fill and sampling was completed Saturday. Orbiter NH3 servicing of both systems A and B will be performed today.”

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Meanwhile, work is proceeding on Solid Rocket Booster (SRB) joint closeouts in the Vehicle Assembly Building (VAB) – with Hold Down Post (HDP) Ordnance preparations in work, following the the Upper shock absorbers installation into the blast containers.

The boosters are set to be joined by ET-122, pending a final decision on which tank to use.

Previously, ET-138 – currently located in High Bay 2E (HB-2E) – was set to fly with Endeavour, until Space Shuttle Program (SSP) managers pushed forward with mission planning for STS-135.

Should Atlantis’ mission receive the required funding in FY2011, the final mission will fly with the “brand new” ET-138, with Endeavour receiving the older ET-122 – which has completed its Hurricane Katrina-related repairs.

To keep their options open, the official allocation of the tanks for these two missions has been delayed until November 9th – with a Program Requirements Control Board (PRCB) presentation (L2) outlining the options (article pending). For the interim, managers are pre-empting a positive outcome for STS-135.

“In the VAB, SRB joint closeout work continues,” added Ground Operations. “The milestone interface chart now reflects ET-122 for STS-134.”

The Pegasus barge has departed for the Michoud Assembly Facility (MAF) in New Orleans on Monday – towed by the Freedom Star – with an aim to pick up ET-122 and ship it to KSC later this month.

“Will be loading the ET transport equipment onto Pegasus at the turn basin, and move Pegasus down to the port. Freedom will pick up the Pegasus and head out to MAF for ET-122 transport,” notes added last week.

“Monday will move the STS-335 left forward from the ARF over to the VAB. That leaves two structures left to transport.”

ET-122 itself is in the final days of production at MAF, with September 20 remaining as the target date for the tank’s departure from New Orleans.

This will mark the final tank to leave MAF for the SSP, although the facility will still host three part built tanks, and one Light Weight Tank (LWT) known as ET-94 – which have one eye on a potential role with a Shuttle Derived Heavy Lift Launch Vehicle (SD HLV) program.

“ET (LMSS/MAF): With ET-122 in Building 420, down to the last planned PVL pour. Have ~3 steel repair pours underneath the intertank feedline,” noted a MAF update on the Shuttle Standup/Integration report (L2).

“Have SRB PAL ramp sprays, and then have the J-Box spray. All hand packs are done. Once they get some trimming done on the aft interface will move in to all systems test, about a three-day event. Still tracking for the need target date of September 17, and plan to ship on September 20.”

Despite the tank being an older and repaired version, the hardware is being treated exactly the same as all recent tanks – which have performed extremely well by way of hardly any TPS foam liberation and a flawless overall tanking and propulsion-related performance.

“ET (NASA/MSFC) Went through a Pre-ship Review at MAF. Had representatives from all over the Program,” noted the Marshall Space Flight Center (MSFC) report on the Standup. “Had a very good review. ET-122 is ready to support its mission (STS-134). Thanks to everyone that supported the review.”

Praise was also received from the Flight Crew office at the Johnson Space Center (JSC), who took part on the Pre-ship review.

“Flight Crew (NASA/JSC) The Flight Crew office attended the ET-122 Pre-ship Review. It was conducted very well. The diligence is appreciated, not only in the engineering, but the communication of the work done on that tank.”

Should STS-135 somehow fail to gain the additional funding – mainly required to pay for a section of the SSP workforce to stay in employment for an extra few months – STS-134 will revert back to riding with ET-138, with ET-122 being allocated to STS-335 (Atlantis’ role as LON – Launch On Need – for STS-134).

In such a scenario, all the unused hardware – which has already been paid for – will be wasted and likely sent to exhibitions, or decommissioned and destroyed – if it can’t find a role in a notional SD HLV program.

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