STS-130: ET-134 Intertank tested – Mission duration change requested

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Following two intertank foam loss events on recent flights, further checks have been carried out on the next External Tank set to fly – ET-134. Additional pull tests have shown good results, as Endeavour prepares to join the stack in the Vehicle Assembly Building (VAB) in readiness for what is now a February 7 launch date – on mission that may be an extended to 13+1 days.

STS-130 Latest:

With two refinements to the STS-130 launch date in a week – based on range availability – Endeavour’s schedule has a large amount of contingency in her flow, a welcome level of flexibility in the event of troubleshooting. However, as of right now, processing is proceeding to plan.

“Preparations are underway to roll over to the VAB. Structural and leak tests being done this week. Are working forward and aft closeouts,” now KSC Integration (L2). “Rollover to VAB is planned for December 12.”

Configuration of display units, testing of Endeavour’s Space Shuttle Main Engines (SSMEs) steering systems and flight surface checks have also been completed in preparation for rollover to the VAB – where she will remain over Christmas.

“MEDS IDP software load is complete. SSME TVC (Thrust Vector Control) checkout, flight control final cycling, and aerosurface final positioning completed,” added NASA Test Director flow latest (L2). “Orbiter bus redundancy test was completed. IMU (Inertial Measurement Unit) checkout and calibration is complete.

“Structural leak tests and final roll preps in pick up. Weekend work: Orbiter positive pressure test.”

The only issue reported – and only the 29th problem in the STS-130 flow – related to the ET side of the orbiter, when a fault was picked up via ET actuator cycling on the LOX Forward Inboard side.

“ET Actuator did not extend when commanded. Engineering is evaluating. Actuator can be R&R’d vertically in the VAB if required,” noted the opening report from the NTD, before later confirming troubleshooting will take place after rollover.

“Update: An electrical checkout of the commands going to both the retract and extend solenoids were performed with nominal results. Further troubleshooting will be performed in the VAB after umbilical mate.”

A2ET-134 and the twin Solid Rocket Boosters (SRBs) are almost ready to receive Endeavour later this month, as mating operations continue inside the VAB’s High Bay 1 (HB-1).

“ET-134 / SRB BI-141 / RSRM 109 (VAB HB-1): Left and Right Hand EDAS Installation is complete. Left and Right Heater Cable Closeouts are complete,” added NTD processing latest on the High Bay operations.

“LH/RH Tunnel Cover Closeouts; LH/RH RT-455 preps/masking complete. RT-455 application continuing. RH contamination was found on the Igniter Fins. Engineering Disposition in work. ET/Orbiter Bipod Installation is scheduled for 2nd shift Friday.

“SRB Pyro Installation is scheduled for 3rd shift Saturday, with SRB closeouts and AFT BSM (Booster Separation Motor) cover installation to follow. SRB FWD and AFT Firing Line Continuity Tests are scheduled for Saturday/Sunday.”

The Orbiter Rollout Mate Review for STS-130/20A will be held by Space Shuttle Program (SSP) managers on December 11.

“The Rollout Review will be performed in conjunction with the OPO (Orbiter Project Office) in preparation for the Program review next week,” added the latest Shuttle Standup/Integration report (L2). “At this point the package is short, with no special topics.”

The reviews will start to pick up this month, as managers head into the Flight Readiness Review (FRR) season, which has already been pre-empted by request for a change of mission duration.

“CR (Change Request) for STS-130/20A will include a mission duration change to push the flight out to 13+1 days,” added Flight Operations and Integration at the Johnson Space Center (JSC). “This is in anticipation that ISSP (International Space Station Program) will add the ‘PMA-3 (Pressurized Mating Adapter) move task’ to the flight. This decision will be made at the December 15.”

ET-134 Confidence:

A3The aforementioned note that no special topics are expected in the early review stage of the mission’s flow towards launch is a good indication that all is going to plan. This was boosted by good results on additional pull tests, which were conducted on ET-134, in order to check the integrity of its intertank foam bonds.

Pull tests – or plug pulls – were called for as a matter of course, following the foam liberation events observed from the top side of the ET-131 intertank during STS-127’s launch. While STS-128’s ET-132 suffered no foam losses, STS-129’s ET-133 suffered a number of liberations – this time from the bottom side of the intertank region.

While foam losses from the bottom side of the tank hold little to no threat of impacting the orbiter during ascent, due diligence within the Space Shuttle Program (SSP) called for assurances that the tank was in good shape.

“ET-134 looks very good, and no issues are expected. Suspect Foam De-bond. Plug pulls complete. Enclosure complete. Conathane applied waiting on disposition for missing primer in plug pull holes,” noted KSC engineering information on the results from the tests.”

A4This short notice testing – along with good results – earned praise from the SSP managers at the Johnson Space Center (JSC), which elaborated on the results via the latest Standup report.

“ET-134: USA (United Space Alliance) did a great job of getting the tank inspected for the potential of missing fasteners on the intertank. None were observed. An additional 10 bond-adhesion tests were performed on the +Z, with all results acceptable.

“The lowest was 30.4 pounds (lbs), with the requirement being 30 lbs. Nine pulled cohesively, with only one pulling adhesively. This one site was swabbed and will be tested for contamination.”

“(SSP Manager) Mr. (John) Shannon congratulated MAF (Michoud Assembly Facility) for their work with KSC regarding the plug-pulls and the inspection of the intertank area. This was important data for the flight rationale.”

L2 members: Documentation – from which the above article has quoted snippets – is available in full in the related L2 sections, now over 4000 gbs in size.

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