STS-134 mission to officially increase by two days and one EVA

by Chris Bergin

Endeavour’s final mission will be officially extended next week, when mission managers approve a Change Request (CR) to add a fourth EVA and a subsequent increase of the mission duration by two days. Originally a 12+1 mission, Endeavour is being tasked with the delivery of the AMS-02 (Alpha Magnetic Spectrometer-02) to the International Space Station (ISS) on February 26.

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The 134th flight of the Space Shuttle Program (SSP) and the 25th and final voyage of the Endeavour, which began service in May 1992 on STS-49, is carrying an ISS mission designation of ULF-6 (Utilization and Logistics Flight 6), and officially baselined into the Flight Definition and Requirements Document (FDRD) on June 25 – initiating production of flight processes to support a No Earlier Than launch date of July 29, 2010.

Among the multitude of payloads Endeavour will carry to orbit with her are AMS-02, the 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.

However, due to problems relating to the AMS payload, a realignment of the Space Shuttle Program (SSP) manifest moved STS-134 to 2011, behind STS-133, with a launch date of February 26, 2011.

As per usual, managers continually align and refine mission content, in order to provide the best possible support of the orbital outpost they are serving with these final shuttle missions. With changes to STS-133’s EVAs, managers pre-empted impacts to STS-134’s mission.

“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 last month. “They are still looking at impacts to STS-134 and looking at a potential fourth EVA.”

That fourth EVA for STS-134 will now be added via a Change Request this coming week, as STS-134 is used to ensure as many get-aheads for STS-135 can be achieved, due to the final mission only carrying a crew of four – which greatly reduces EVA capability.

“There is a CR coming next week for STS-134/ULF6 to increase the mission duration by two days and add an EVA,” noted Flight Operations and Integration on the latest Shuttle Standup/Integration report (L2). “FO&I will get with Orbiter and bring a risk discussion on MMOD (Micro-Meteoroid Orbital Debris – due to extra time on orbit) as part of that decision process.”

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Due to the slip of the launch date, Endeavour is in a very relaxed processing flow, with plenty of contingency time available in the event of an engineering issue. Regardless, no issues have been reported insider Endeavour’s Orbiter Processing Facility (OPF-2) for some time, with the orbiter already undergoing closeout operations.

“Completed ET (External Tank) door functional. Will continue with BLT (Boundary Layer Transition) mods. Also completed the RSB (Rudder Speed Brake) inspections; Engineering is looking at the tile there,” noted KSC Ground Operations (L2). “Working some clean up on the RSB corrosion.”

With OMS (Orbital Maneuvering System) oxidizer and fuel helium pressure regulator leak checks, along with the related functional testing complete, preparations have moved into checking the Thrust Vector Control (TVC) system on the Space Shuttle Main Engines (SSMEs).

Meanwhile, over in High Bay 4E (HB-4E) of the Vehicle Assembly Building (VAB), ET-122 is undergoing checks in the aptly named checkout cell, as the plan continues to track the use of the refurbished tank on STS-134, allowing the newer ET-138 to fly with Atlantis on what remains a notional STS-135 mission.

As with ET-137 out at the pad with Discovery as part of the STS-133 stack, and ET-138, engineers remain tasked with pull/plug tests on the intertank region of the tank, ensuring they are confident of no further repeats of the foam liberation seen on a couple of missions last year.

“ET-122 (VAB HB-4E): TPS-001 Bond Adhesion Tests: Conothane application and mold installation are complete; ready for PDL (foam) application,” noted the NASA Test Director (NTD) processing report (L2), with ET engineers also noting the X-ray inspections that are ongoing since a flight washer was found inside ET-138’s LOX Feedline.”

“ET-122 Did do the intertank bond adhesion test. Nothing was critical, they all pulled cohesively. They were all above the minimum 30 psi requirement (pulled 31-70 psi),” added Lockheed Martin’s latest report (L2).

“The Lockheed Martin team pulled out of there and the USA team will proceed downstream with the closeout of those test areas. The team has been making good progress with the feedline component X-rays, so far there are no findings.”

Nominal work is also continuing on the twin Solid Rocket Boosters (SRBs), which are being stacked in High Bay 1 (HB-1) of the VAB. ET mate with the boosters will be held back until the latest opportunity, in order to allow for a final decision on which tank will fly with STS-134.

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