Sources are noting that Marshall Space Flight Center (MSFC) have seen their request for a design change to the External Tanks dismissed by managers at the Johnson Space Center during today’s heated PRCB (Program Requirements Control Board) meeting.
Meanwhile, seperate sources are claiming John Muratore, Manager for Shuttle Systems Engineering and Integration, has been re-assigned to a position that has no influence on Shuttle decisions.
Remaining issues with the tank comes as a surprise, following encouraging wind tunnel testing – which is still on-going – on the modified ET test article.
The ice/frost ramps appear to be the focus of attention again, with further work on ‘shaving’ the ramps down being part of the Wind Tunnel process.
A small section of foam did liberate from the ice/frost ramp during a 30 second high aerodynamic pressure run, although that was believed to be over 1000 psf – much higher than a Shuttle can expect to encounter during ascent.
To aid the reduction in foam shedding, NASA recently confirmed they would fly STS-121 with a ‘Low Q’ mission profile, which will keep the stack below 735 psf during the ride uphill. Wind Tunnel tests below 735 psf encountered no problems during evaluations.
It is possible, though not confirmed, that MSFC requested that the ice/frost ramps on all future External Tanks, including ET-119 – currently awaiting Discovery’s arrival for mating in the VAB (Vehicle Assembly Building) – undergo the extra ‘shaving down’ as undertaken at the wind tunnel tests.
Discovery is currently schedule to fly this July on STS-121 – the second of two test flights prior to the re-start of International Space Station (ISS) assembly flights.
A re-design would have likely led to a 12-18 month downtime period for the Shuttle fleet, a highly undesirable option for the Program.
LIVE UPDATE PAGES
Shuttle managers are set to give an update to the status of STS-121 during tomorrow’s media conference.
NASA Administrator Michael Griffin and Associate Administrator for Space Operations William Gerstenmaier will brief the media at 11 a.m. EDT. The briefing will be held at NASA Headquarters in Washington, DC.
Space Shuttle Program Manager Wayne Hale will join them electronically from NASA’s Marshall Space Flight Center, Huntsville, Ala. NASA TV will air the briefing live.
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