Launch processing for Shuttle Atlantis is going to plan, but her External Tank (ET-118) has been delayed – and won’t arrive at the Kennedy Space Center until the middle of June, according to a presentation at today’s PRCB (Program Requirements Control Board) meeting.
Atlantis’ primary role is the re-start of International Space Station (ISS) assembly on STS-115 in late August. However, she is also required to support her sister Discovery on the rescue mission STS-300.
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ET-118 was set to begin its journey to KSC on Wednesday, but despite extra workers being placed on finishing the final ‘shakedown’ of the tank – including the replacement of its ECO (Engine Cut Off) sensors, the tank won’t arrive until the 10th of June at the earliest.
Some extra ‘finishing’ of the tank may take place at KSC, which would involve a team of Lockheed Martin workers from the Michoud Assembly Facility (MAF) heading to KSC.
‘ET-118 planned ship changed from 5/31 to 6/5 (KSC on-dock, 6/10),’ noted the PRCB document. ‘ET Project working with KSC and USA (United Space Alliance) to minimize impact on already compressed KSC processing flow. Plan developed to complete MAF specific processing requirements and defer remaining work packages to KSC as unplanned work.
‘Preliminary assessment indicates that work can be absorbed with no serial impact to current plans (for ECO Sensor R&R). Assessment will be performed at MAF prior to ship to establish acceptability for shipment.’
Given the work that has to be completed at KSC, the tank won’t be ready for its transfer from the checkout cell to stacking with the twin Solid Rocket Boosters until around July 12.
That date could still be reduced for Atlantis’ LON (Launch On Need) date of August 17, given the amount of time it takes for the Shuttle to be readied for launch – past the point of being stacked in the VAB (Vehicle Assembly Building).
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However, that LON date may now be simply a case of launching on the same timeline as Atlantis would for STS-115.
‘Our processing flow in the OPF (Orbiter Processing Facility) is really based on mission processing,’ said Shuttle Launch Director Michael Leinbach during Wednesday’s Space Shuttle update.
‘It turns out that the capability of the International Space Station has to support our crew in the event of a rescue says that we can stay on that processing schedule in the OPF, we can rollout on July 25 – whether it’s for STS-115 or the rescue mission.
‘So our plan on the OPF scheduling doesn’t change.’
Meanwhile, work on the External Tank that is planned to launch with Discovery on the third mission of the year, STS 116 – NET (No Earlier Than) December 14, 2006, is also in a critical path, although it currently supports the targeted launch date.
ET-123 is currently set to be shipping from MAF on September 4.
Another ET-118 related article will follow, with documented information on potential ECO (Engine Cut Off) sensor R&R at KSC, following a different proceedure to that seen on ET-119 ECO sensor R&R at KSC.