STS-134 officially moved to April 19 – ET-122 stringers may be inspected

by Chris Bergin

Endeavour’s final mission has slipped to the second half of April – as expected – due to the realignment of her older sister’s STS-133 mission to February 24. The April 19 mission, which remains under the command of Mark Kelly, has a large amount of contingency time in its flow, which will allow for inspections of Endeavour’s External Tank (ET-122) should managers request additional data on its stringers.

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Endeavour’s final mission is tasked with launching the AMS-02 (Alpha Magnetic Spectrometer-02) to the International Space Station (ISS), whilst carrying the Express Logistics Carrier 3 (ELC-3). Also riding with Endeavour are the 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.

The youngest orbiter in the fleet is finally coming to the end of her only Interim Problem Report (IPR-20) of late, relating to a sensor on her LH (Left Hand) OMS (Orbital Maneuvering System) pod Main Engine Ignition (MEI), which is part of a sensor suite used to gain data on MEI Acoustic and SSME (Space Shuttle Main Engine) Ignition Overpressure (IOP) Environments.

Specific to an acoustic sensor called V08Y9704A – which failed to channelize during testing last year – the review of troubleshooting is aiming to close the IPR.

Other work which has been carried out in her Orbiter Processing Facility (OPF-2) included the checkout of the orbiter’s Flash Evaporator System (FES) – used to provide cooling to the ship’s systems when the vehicle’s Payload Bay Doors (containing the orbiter’s radiators) are closed – and the closeouts of her wings.

Due to the slips suffered by Discovery’s STS-133 mission, Endeavour’s milestones have also been moved to the right. The next key event for the STS-134 stack will be the mating of the twin Solid Rocket Boosters (SRBs) with ET-122.

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“The planning date for ET mate to SRBs is no earlier than 19 January 2011; Program direction will ultimately determine the date,” was the most recent update from the NASA Test Director (NTD), although this date will remain under review until next week.

The two boosters are currently stacked and awaiting ET-122 in High Bay 3 (HB-3) of the Vehicle Assembly Building (VAB). Notably, some platform rearrangement has already taken place, ahead of a potential decision to carry out Non Destructive Evaluation (NDE) scans of the tank’s stringers once mated.

“SRB BI-145/RSRM 113 (VAB HB-3): The AP-99 platforms have been removed from ‘B’ platform to aid tank access for possible ET stringer modifications,” added the NTD report (L2).

“The AP-47 platforms will be removed from ‘E’ platform as well; that work is scheduled to be performed Friday.”

Should managers decide to carry out stringer modifications – likely via the same procedure which is currently being carried out on ET-137 by installing radius blocks – the STS-134 launch date would not be impacted.

Such a decision will be based on the ongoing investigation into the stringer crack issue, with ET-122’s Michoud Assembly Facility (MAF) manufacture date of 2000 several years prior to ET-137 and ET-138, potentially clearing the tank from the root cause of ET-137’s cracks – mainly specific to a “mottled surface on the stringers, resulting in reduced fracture toughness.

While ET-122 – which was repaired and brought back into service after receiving damage during Hurricane Katrina – remains in the High Bay 4E (HB-4E) checkout cell, engineers are working on the tank’s Ground Umbilical Carrier Plate (GUCP) – in order to avoid the leak which scrubbed STS-133’s opening launch attempt in November.

“ET-122 (VAB HB-4E): The GUCP QD (Quick Disconnect) will be removed Friday to perform concentricity measurements. In addition, the flight seal will be R&R’d,” added the NTD report. “The QD will be re-installed following ET/SRB mate. Non-interference processing is continuing as resources allow. LO2/LH2 Umbilical closeouts continue.”

STS-134 Crew:

Endeavour’s final flight will be commanded by Mark Kelly, who is currently on an leave of absence due to the assassination attempt on his wife – Congresswoman Gabrielle Giffords. With the US Navy Captain’s brother, Scott Kelly, currently commanding Expedition 26 onboard the ISS, managers have praised the ISS team for keeping the commander briefed on the tragic incident of January 8.

MOD management cancelled the upcoming STS-134 flight sims out of respect, as opposed to any request by the crew, but have accepted – via a recommendation from Commander Mark Kelly – to install astronaut Rick Sturckow as the backup commander for the mission to aid with upcoming sim work.

“I recommended to my management that we take steps now to prepare to complete the mission in my absence, if necessary,” Kelly said via NASA PAO. “I am very hopeful that I will be in a position to rejoin my STS-134 crew members to finish our training.”

“Mark is still the commander of STS-134,” added Peggy Whitson, chief of the Astronaut Office. “He is facing many uncertainties now as he supports Gabrielle, and our goal is to allow him to keep his undistracted attention on his family while allowing preparations for the mission to progress.

“Designating a backup allows the crew and support team to continue training, and enables Mark to focus on his wife’s care.”

(All images via L2 – bar the NDE scan photo, via KSC/

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