Tag: APU
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STS-134: APU heaters perform without issue as Endeavour launches
Shuttle Endeavour is back in space for what is scheduled to be her final mission. A nominal countdown, which included an issue-free tanking, resulted in an on time launch at 8:58am Eastern. The countdown also provided a full test of the mitigation effort on the Auxiliary Power Unit (APU-1) Heater system issue which caused the…
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STS-134 begins countdown – VADER payload struggles with launch delay
Endeavour remains on track for launch on Monday, as she hit the start of her S0007 Launch Countdown operation on time at 7am Friday morning. No issues are being worked on the vehicle, although a meeting on Thursday confirmed a decision not to reopen the Payload Bay in order to help the STP-H3 VADER experiment,…
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STS-134: Endeavour closing in on S0007 – ALCA-2 root cause update
Endeavour is on track to head back into Launch Countdown (S0007) operations on Friday, as her engineers complete tasks associated with reconnecting the ordnance to the stack and closeouts. All retests on the Aft Load Controller Assembly (ALCA-2) are complete and nominal, with a potential lead on the root cause of the April 29 launch…
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STS-134 moves to NET May 16 target amid APU wiring and thermos work
Endeavour’s final mission is now tracking a No Earlier Than (NET) May 16 launch date, following a Program level meeting to evaluate the schedule for the troubleshooting work on the orbiter’s Auxiliary Power Unit (APU-1) heater system. Work has – and continues to – focus on the Aft Load Controller Assembly (ALCA-2), while additional work…
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STS-134: Endeavour receives her new LCA – Blown driver examined
Teams at launch pad 39A at the Kennedy Space Center, FL have completed operations to install a replacement Aft Load Controller Assembly (ALCA) into one of Endeavour’s aft avionics bays. Meanwhile, the ALCA that failed during the April 29th launch attempt for Endeavour is undergoing testing to isolate the cause of the failure and enable…
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STS-134: Managers move launch to NET May 10 – APU/LCA work continues
NASA managers have internally refined Endeavour’s troubleshooting schedule on Monday, placing STS-134 on a NET (No Earlier Than) launch date of May 10. The schedule continues to be provisional, as engineers press on with the complex work of replacing the Aft “Load Control Assembly” (ALCA-2) – the likely cause of the APU 1 heater failure…
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STS-134: Launch slips to NET May 8 as APU troubleshooting finds LCA fault
Endeavour’s critical – and final – mission to the International Space Station (ISS) has been delayed until at least May 8, following an engineering evaluation into her Auxiliary Power Unit 1 (APU-1), which suffered from a heater problem, breaking Launch Commit Criteria rules. The investigation found the root cause relates to a hybrid driver inside…
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Endeavour suffers from troublesome countdown, APU issue scrubs launch
Shuttle Endeavour – the youngest orbiter in the fleet – was preparing for her final hours prior to launch, after the Mission Management Team (MMT) met to approve the tanking of ET-122. However, several issues popped up in the count, most notably with an OMS tank issue, which was then resolved, prior to a heater issue on Auxiliary Power…
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STS-119: LH2 leak during tanking postpones launch to March 15
STS-119’s opening launch attempt has been scrubbed until Sunday, March 15,, following a LH2 leak during tanking. The leak related to a carrier plate that is attached to the intertank area of the ET, with attempts to cycle the associated valve to reduce the leak to acceptable proving to be unsuccessful. Scrub info: Work at the…