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.




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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.

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.

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

"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.

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?

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).

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.

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...

(Hallerb) wrote in with:

[...] Its HUGH

No, *my* Hugh; The hole has a Tommy.


(ugh, I'm being bad, but I just can't resist the temptation. There
does seem to be some improvement in typing, though)

/dps