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#1
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Shuttles going to be grounded a LONG time.
"Hallerb" wrote in message ... The RCC cant be redesigned overnite. How will ISS remain operational if the shuttle grounding goes to a challenger like time? Don't know but I think when the shuttle is up and running the first crew will need to include some interior redecorators. -----= Posted via Newsfeeds.Com, Uncensored Usenet News =----- http://www.newsfeeds.com - The #1 Newsgroup Service in the World! -----== Over 80,000 Newsgroups - 16 Different Servers! =----- |
#2
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Shuttles going to be grounded a LONG time.
The RCC cant be redesigned overnite. How will ISS remain operational
if the shuttle grounding goes to a challenger like time? Depends on how long the CMG's last, I suppose. Well, and whether the funding for Progress/Soyuz holds up. Now, as for whether an "RCC redesign" (or something similarly time consuming) is going to be needed, well, we can start with the recommendation of the board: Before return to flight, for missions to the International Space Station (ISS,) develop a practicable capability to inspect and effect emergency repairs to the widest possible range of damage to the Thermal Protection System (TPS,) including both tile and Reinforced Carbon Carbon (RCC,) taking advantage of the additional capabilities available while in proximity to and docked at the ISS. http://www.caib.us/news/press_releases/pr030627.html The key words here are "widest possible range of damage". Presumably the word "possible" implies: within the constraints of the existing RCC. Here's a sample article which talks a bit about RCC repair options being worked but doesn't go into any details: http://spaceflightnow.com/shuttle/st...620tilerepair/ Another good source (partly worth reading simply because it was written pre-Columbia) is: http://www.nap.edu/books/0309059887/html/47.html The relevant sentence is: effective repair of the RCC leading edges would be very difficult because the repairs would have to survive exposure to very high temperatures during reentry Again, this doesn't go into details, though, and surely the priority of this item has gone up even if the danger of another RCC breach may not have. |
#3
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Shuttles going to be grounded a LONG time.
One thing being looked at is filling a potential breach with MA25 or if RF
transparency is needed then SLA220. The original tile repair option from 1981 was a pressurized gun filled with MA25. Both are real good insulators, excellent ablators, and very light. For the CGM one has failed and a second is sick. They can survive with two CGMs and some help from thrusters, after that it's all thrusters and would depend on fuel margins. An EVA was planned on 12A.1 to replace the failed CGM, when that will happen is debatable. I bet the shuttle will fly by Nov/Dec this year. Cheers! Bit "Jim Kingdon" wrote in message news The RCC cant be redesigned overnite. How will ISS remain operational if the shuttle grounding goes to a challenger like time? Depends on how long the CMG's last, I suppose. Well, and whether the funding for Progress/Soyuz holds up. Now, as for whether an "RCC redesign" (or something similarly time consuming) is going to be needed, well, we can start with the recommendation of the board: Before return to flight, for missions to the International Space Station (ISS,) develop a practicable capability to inspect and effect emergency repairs to the widest possible range of damage to the Thermal Protection System (TPS,) including both tile and Reinforced Carbon Carbon (RCC,) taking advantage of the additional capabilities available while in proximity to and docked at the ISS. http://www.caib.us/news/press_releases/pr030627.html The key words here are "widest possible range of damage". Presumably the word "possible" implies: within the constraints of the existing RCC. Here's a sample article which talks a bit about RCC repair options being worked but doesn't go into any details: http://spaceflightnow.com/shuttle/st...620tilerepair/ Another good source (partly worth reading simply because it was written pre-Columbia) is: http://www.nap.edu/books/0309059887/html/47.html The relevant sentence is: effective repair of the RCC leading edges would be very difficult because the repairs would have to survive exposure to very high temperatures during reentry Again, this doesn't go into details, though, and surely the priority of this item has gone up even if the danger of another RCC breach may not have. |
#4
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Shuttles going to be grounded a LONG time.
I bet the shuttle will fly by
Nov/Dec this year. Cheers! Bit Boy are you going to be wrong. How about a $50 gift certificate if the shuttle isnt in orbit by the end of this year? I love eating out at others expense |
#5
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Shuttles going to be grounded a LONG time.
"bitflip" wrote in
: First of all, welcome back, Tom! You have been sorely missed. One thing being looked at is filling a potential breach with MA25 or if RF transparency is needed then SLA220. The original tile repair option from 1981 was a pressurized gun filled with MA25. Both are real good insulators, excellent ablators, and very light. MA-25 did have some weaknesses, like a tendency to foam up in vacuum. Boeing has developed a modified version called MA-25S that appears to address the concerns (caveat: not all the arc jet and vacuum chamber tests are complete). But assuming no showstoppers, they think they can deliver flight-ready materials and tools by December. For the CGM one has failed and a second is sick. They can survive with two CGMs and some help from thrusters, after that it's all thrusters and would depend on fuel margins. An EVA was planned on 12A.1 to replace the failed CGM, when that will happen is debatable. I thought it was on STS-114/ULF-1 (the same flight carrying up the replacement CMG). You really want to have as much CMG capability available before ISS goes through its highly asymmetric configs (12A and 12A.1). I bet the shuttle will fly by Nov/Dec this year. I see you still have that youthful optimism. :-) My bet is March/April '04, with the pacing items being RCC repair capability and the ET bolt-catcher fix. -- JRF Reply-to address spam-proofed - to reply by E-mail, check "Organization" (I am not assimilated) and think one step ahead of IBM. |
#6
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Shuttles going to be grounded a LONG time.
I see you still have that youthful optimism. :-) My bet is March/April '04, with the pacing items being RCC repair capability and the ET bolt-catcher fix. Do you really think we can fly without a rCC redesign? I mean foam WILL flake and look at that hole Can such a LARGE hole be succesfully fixed in orbit? |
#7
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Shuttles going to be grounded a LONG time.
Do you really think we can fly without a rCC redesign? I mean foam
WILL flake and look at that hole That's more of an argument for a foam redesign. The bipod will happen before return to flight, and hopefully the shedding of smaller pieces will be fixed rather than ignored (although not necessarily for return to flight). |
#8
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Shuttles going to be grounded a LONG time.
Jim Kingdon wrote in
news Do you really think we can fly without a rCC redesign? I mean foam WILL flake and look at that hole That's more of an argument for a foam redesign. The bipod will happen before return to flight, and hopefully the shedding of smaller pieces will be fixed rather than ignored (although not necessarily for return to flight). The CAIB probably feels similarly. Even before the latest foam impact test, the CAIB's "working scenario" assumed that the foam opened up a breach in the RCC. Even so, Admiral Gehman stated they didn't feel a leading-edge redesign was necessary as long as the foam hazard was fixed, and that he saw no show-stoppers to return-to-flight within 6-9 months. The *only* things that changed due to the test are that 1) the CAIB's assumption is now supported by test data, and 2) we have nice, dramatic pictures of it for the Chicken Littles to wet their pants over. I see no reason for the CAIB to change its stance now that it has more data to back up the assumption that was behind its previous statements and recommendations. -- JRF Reply-to address spam-proofed - to reply by E-mail, check "Organization" (I am not assimilated) and think one step ahead of IBM. |
#9
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Shuttles going to be grounded a LONG time.
I see no reason for the CAIB to change its stance now that it has more data
to back up the assumption that was behind its previous statements and recommendations. I think the size of that hole will be a show stopper. Its HUGH and shows just how vulernable the RCC is. Plus did you notice that immediately after the test the report got delayed a month? NASA admits the foam will never be 100%, given that the RCC must be improved. Bet nasa has a redesign team already working on it... |
#10
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Shuttles going to be grounded a LONG time.
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