NASA remains confident that they can continue to work towards a May launch window for Shuttle Discovery’s STS-121 – the second Return to Flight test mission.
Workers at the Kennedy Space Center (KSC) require both External Tanks “ET-119” and “ET-118” to arrive at the spaceport in time to support launch processing for a May window that starts on May 3.
ET-119, the first of the ETs to arrive back at KSC minus its PAL (protuberance air load) ramp, is on schedule to be shipped from the Michoud Assembly Facility in New Orleans on March 3 – arriving in Port Canaveral on March 8.
ET-118, to be used on Atlantis’ STS-115 mission in July, is also required back at KSC before Discovery launches. This is to support Atlantis’ support role of STS-300, the Contingency Shuttle Crew Support (CSCS) mission which would be utilised in the event of a worse case scenario of the STS-121 crew requiring rescue from the ‘safe haven’ of the International Space Station (ISS), due to irreparable damage to Discovery during ascent.
The LON (Launch On Need) window for an STS-300 mission – based on consumables to support a stranded STS-121 crew on the ISS – is currently 59 days, far more than previous thought, thus raising confidence levels for the ET delivery dates being in support of all required elements for a May launch window of Discovery.
‘ET 119 schedules continue to show March 3 as the ready to ship date, with an on dock date of around March 8,’ said Kyle Herring, NASA PA for the Program at the Johnson Space Center in Houston. ‘That has not changed and supports the May window.
‘ET 118 is second tank and schedules indicate it supports CSCS.’
A firm shipping date for ET-118 is yet to be revealed, as work is still being undertaken with the removal process of the PAL ramp, but sources have indicated that an internal estimate for shipping the tank is April 7 – arriving into dock at KSC for April 12.
Should both tanks remain on schedule for arrival at KSC on their respective dates, launch processing would have to proceed without interruption or delay to support a potential lift-off of Discovery before the end of the May window (May 23).
‘It can be done, but it’s critically important that we have a clean 121 mission – so the last thing we’re going to is compromise that through tight processing schedules for the sake of making the May window,’ noted a KSC source. ‘On the flip side, we know how confident we are in 121 being a successful test flight.
‘We look forward to regular launch operations being initiated, after Discovery confirms wheel stop after her mission.’
Discovery is currently being processed in OPF (Orbiter Processing Facility) High Bay 3. The SRB (Solid Rocket Booster) segments that will make up the boosters for STS-121 have arrived at KSC and are being prepared for assembly and stacking.
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