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Tile and RCC repair for return to flight
I think someone mentioned something about whether RCC repair was the
long pole in the tent for shuttle return to flight. Well, I thought I'd check on this. The short summary seems to be that tile repair should be ready, and RCC repair indeed is much more of an unknown at this point. My source is http://www.nasa.gov/news/highlights/returntoflight.html specifically the big PDF (Implementation Plan for Space Shuttle Return to Flight and Beyond, revision 2.2, 30 Aug 2004) which says: RCC Repair The main challenges to repairing RCC are maintaining a bond to the RCC coating during entry heating and meeting very small edge step requirements. The RCC repair project is pursuing two complementary repair concepts that together will enable repair of a range of RCC damage: Plug Repair and Crack Repair. Plug Repair consists of an insert intended to repair holes in the WLE with sizes from 0.5 in. to 4 in. in diameter. Crack Repair uses a material application intended to fill cracks and small holes in the WLE. Both concepts are expected to have limitations in terms of damage characteristics, damage location, and testing/analysis. Schedules for design, development, testing, evaluation, and production of these concepts are in work. A third repair concept, RCC rigid overwrap, encountered problems during devel- opment and was shown to be infeasible to implement in the near term; as a result, it was deleted from considera- tion for RTF. NASA is continuing research and develop- ment on a long-term, more flexible RCC repair technique for holes over 4 in. in diameter. This effort is still in the concept definition phase and is much less mature than the tile repair material study. NASA is evaluating concepts across six NASA centers, 11 contrac- tors, and the United States Air Force Research Laboratory. Although we are aggressively pursuing RCC repair, it is too early in development to forecast a completion date. Tile Repair NASA has made significant progress in developing credible tile repair processes and materials. A formulation derived from an existing, silicone-based, cure-in-place ablator showed good thermal performance results in development testing in 2003. Tests confirmed that the repair material adheres to aluminum, primed aluminum, tile, strain isolation pads, and tile adhesive in vacuum and cures in vacuum. After these successful tests, NASA transitioned to characteriza- tion and qualification testing. Detailed thermal analyses and testing are under way to confirm that the material can be applied and cured in the full range of orbit conditions. It goes on with more about the tile repair (and of course the PDF, all 284 pages of it, is full of similar details about all aspects of return to flight). |
#2
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Jim Kingdon wrote
[Various excisions performed] My source is http://www.nasa.gov/news/highlights/returntoflight.html specifically the big PDF (Implementation Plan for Space Shuttle Return to Flight and Beyond, revision 2.2, 30 Aug 2004) which says: RCC Repair NASA is continuing research and develop- ment on a long-term, more flexible RCC repair technique for holes over 4 in. in diameter. IOW, they're still looking for a way to repair the size of hole thought to be responsible for the destruction of Columbia? http://www.memagazine.org/backissues.../thetrail.html Investigators launched a piece of foam at the RCC panel 8 at 530 mph at an angle of about 20 degrees. The impact blew a large hole in the panel, some 16 inches square. Thermal analysis performed by the NASA investigation team indicated that a hole 10 inches across would have been enough to bring the orbiter down and would have corresponded consistently with the sensor data of Columbia's last flight. |
#3
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"Allen Thomson" IOW, they're still looking for a way to repair the size of hole thought to be responsible for the destruction of Columbia? No, they are not still looking. The repair of a hole similar to the one on Columbia was never feasible. This has been in the press and related by NASA people numerous times from the beginning of the return to flight efforts. Did you miss these reports, or is your question rhetorical? |
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