Re: RCC panels

[Hallerb]

>
>> since foam can never be 100%
>
>You can say that again.....oh wait...you did....about 37 times now.
>

Too bad nasa managers didnt ponder what damage foam could do???

[Lynndel Humphreys]

"Hallerb" > wrote in message
...
> >
> >> since foam can never be 100%
> >
> >You can say that again.....oh wait...you did....about 37 times now.
> >
>
> Too bad nasa managers didnt ponder what damage foam could do???

or buzzards or space debris ...make the count 38




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[Kegwasher]

Brian Gaff wrote:

> Being in a pondering frame of mind, I started thinking about the design
> of the rcc panels, which as we learned, have thickened areas to help with
> the strength. I sort of wondered that maybe if an X thickened structure
> had been used instead of leaving that large area unsupported, the out come
> of an
> impact might have been different. Maybe there were just not enough
> support points?
>
> PS, everyone seems a tiny bit testy here these last few days, must be the
> hormones...:-)
>
> Brian
>

That was similar to what I was thinking. Seems they have proven pretty
conclusively that the RCC panels as is are not adequate. It would not seem
to be such a redesign effort to add stiffeners behind the panel to reduce
possible damage from Foreign objects. I was also interested to read that
there have been smaller leaks on prior flights that were not considered
major. Some kind of asbestos blanket behind the panels does not sound so
crazy. Yes, it would add weight but not as much as an almost completely
useless ejection seat.

Chris

[Dale]

On Sat, 26 Jul 2003 23:13:16 +0200, Kegwasher > wrote:

>Brian Gaff wrote:
>> PS, everyone seems a tiny bit testy here these last few days, must be the
>> hormones...:-)

Maybe synchronizing our mood rings to black was a bad idea?

>That was similar to what I was thinking. Seems they have proven pretty
>conclusively that the RCC panels as is are not adequate. It would not seem
>to be such a redesign effort to add stiffeners behind the panel to reduce
>possible damage from Foreign objects. I was also interested to read that
>there have been smaller leaks on prior flights that were not considered
>major. Some kind of asbestos blanket behind the panels does not sound so
>crazy. Yes, it would add weight but not as much as an almost completely
>useless ejection seat.

My (admittedly limited) understanding is that the hole in the RCC had the
effect of intensifying the local heating of the entering plasma. If that is the
case, I'm not sure asbestos blankets would help much, once the damage
has been done.

But then, I'm no engineer, except when I'm playing with my trains :)

Dale

[Kegwasher]

Dale wrote:

> On Sat, 26 Jul 2003 23:13:16 +0200, Kegwasher >
> wrote:
>
>>Brian Gaff wrote:
>>> PS, everyone seems a tiny bit testy here these last few days, must be
>>> the hormones...:-)
>
> Maybe synchronizing our mood rings to black was a bad idea?
>
>>That was similar to what I was thinking. Seems they have proven pretty
>>conclusively that the RCC panels as is are not adequate. It would not
>>seem to be such a redesign effort to add stiffeners behind the panel to
>>reduce
>>possible damage from Foreign objects. I was also interested to read that
>>there have been smaller leaks on prior flights that were not considered
>>major. Some kind of asbestos blanket behind the panels does not sound so
>>crazy. Yes, it would add weight but not as much as an almost completely
>>useless ejection seat.
>
> My (admittedly limited) understanding is that the hole in the RCC had the
> effect of intensifying the local heating of the entering plasma. If that
> is the case, I'm not sure asbestos blankets would help much, once the
> damage has been done.
>
> But then, I'm no engineer, except when I'm playing with my trains :)
>
> Dale

I was using the 'belt and suspenders' line of reasoning. In other words,
make changes to reduce the chance of foam coming off, reduce the effect of
a similar hit in the future and then if possible make changes to reduce the
amount of damage caused.

Chris

[Dale]

On Sun, 27 Jul 2003 09:32:28 +0200, Kegwasher > wrote:

>>>That was similar to what I was thinking. Seems they have proven pretty
>>>conclusively that the RCC panels as is are not adequate. It would not
>>>seem to be such a redesign effort to add stiffeners behind the panel to
>>>reduce possible damage from Foreign objects. I was also interested to
>>>read that there have been smaller leaks on prior flights that were not
>>>considered major. Some kind of asbestos blanket behind the panels does
>>>not sound so crazy. Yes, it would add weight but not as much as an almost
>>>completely useless ejection seat.
>>
>> My (admittedly limited) understanding is that the hole in the RCC had the
>> effect of intensifying the local heating of the entering plasma. If that
>> is the case, I'm not sure asbestos blankets would help much, once the
>> damage has been done.
>
>I was using the 'belt and suspenders' line of reasoning. In other words,
>make changes to reduce the chance of foam coming off, reduce the effect of
>a similar hit in the future and then if possible make changes to reduce the
>amount of damage caused.

That certainly seems like sound reasoning to me. I was just questioning
whether asbestos would really offer much protection after a breach of the RCC
panels. I find it hard to believe that such a critical surface apparently wasn't
tested more exhaustively long ago. Is it much stronger and more resilient when
new? I'm kinda shocked that those shooting foam at it recently were reportedly
so surprised by the results.

Dale

[Kegwasher]

Dale wrote:

> On Sun, 27 Jul 2003 09:32:28 +0200, Kegwasher >
> wrote:
>
>>>>That was similar to what I was thinking. Seems they have proven pretty
>>>>conclusively that the RCC panels as is are not adequate. It would not
>>>>seem to be such a redesign effort to add stiffeners behind the panel to
>>>>reduce possible damage from Foreign objects. I was also interested to
>>>>read that there have been smaller leaks on prior flights that were not
>>>>considered major. Some kind of asbestos blanket behind the panels does
>>>>not sound so crazy. Yes, it would add weight but not as much as an
>>>>almost completely useless ejection seat.
>>>
>>> My (admittedly limited) understanding is that the hole in the RCC had
>>> the effect of intensifying the local heating of the entering plasma. If
>>> that is the case, I'm not sure asbestos blankets would help much, once
>>> the damage has been done.
>>
>>I was using the 'belt and suspenders' line of reasoning. In other words,
>>make changes to reduce the chance of foam coming off, reduce the effect of
>>a similar hit in the future and then if possible make changes to reduce
>>the amount of damage caused.
>
> That certainly seems like sound reasoning to me. I was just questioning
> whether asbestos would really offer much protection after a breach of the
> RCC panels. I find it hard to believe that such a critical surface
> apparently wasn't tested more exhaustively long ago. Is it much stronger
> and more resilient when new? I'm kinda shocked that those shooting foam at
> it recently were reportedly so surprised by the results.
>
> Dale


Good point, I just used asbestos as a general term for some kind of
temperature diffusing blanket. I may have the physics wrong but it seems
that at very low pressure and high energy if the plasma had been forced to
flow through a batting of some sort it would have lost a large amount of
energy by the time it penetrated to the structure. Any solid surface would
be eaten through by the torch effect but a silicon or asbestos blanket
would not.


Chris

[Dale]

On Sun, 27 Jul 2003 10:17:03 +0200, Kegwasher > wrote:

>> That certainly seems like sound reasoning to me. I was just questioning
>> whether asbestos would really offer much protection after a breach of the
>> RCC panels. I find it hard to believe that such a critical surface
>> apparently wasn't tested more exhaustively long ago. Is it much stronger
>> and more resilient when new? I'm kinda shocked that those shooting foam at
>> it recently were reportedly so surprised by the results.
>>

>Good point, I just used asbestos as a general term for some kind of
>temperature diffusing blanket. I may have the physics wrong but it seems
>that at very low pressure and high energy if the plasma had been forced to
>flow through a batting of some sort it would have lost a large amount of
>energy by the time it penetrated to the structure. Any solid surface would
>be eaten through by the torch effect but a silicon or asbestos blanket
>would not.

Assuming that's the case, your idea sounds like a very good one to me. Maybe
you could offset at least some of the added weight of the blanket by removing
some ballast from the nose.

I'm obviously way too wimpy to ever cut it as an astronaut, but I'd feel better with
something stuffed in behind the RCC. Even if it were only there for psychological
effect :)

Dale

[LooseChanj]

On or about Sat, 26 Jul 2003 23:13:16 +0200, Kegwasher
> made the sensational claim that:
> That was similar to what I was thinking. Seems they have proven pretty
> conclusively that the RCC panels as is are not adequate. It would not seem
> to be such a redesign effort to add stiffeners behind the panel to reduce
> possible damage from Foreign objects. I was also interested to read that
> there have been smaller leaks on prior flights that were not considered
> major. Some kind of asbestos blanket behind the panels does not sound so
> crazy. Yes, it would add weight but not as much as an almost completely
> useless ejection seat.

Well, they're fine so long as you don't hit them *just* right. The major
problem is how to repair the RCC panels in a way that will provide
aerodynamic integrity as long as possible. It was the drag from the left
wing overloading control which finally caused the breakup.
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[JGM]

LooseChanj wrote:

>Well, they're fine so long as you don't hit them *just* right.

I'm not sure this has been determined, even if, as Gehman implies, the foam
is history. We now know of several other, smaller, RCC breaches, so the RCC is
by no means impervious except in freak cases. Have these all been determined
to be the result of foam strikes?

>The major
>problem is how to repair the RCC panels in a way that will provide
>aerodynamic integrity

Are you talking about repair on-orbit? Because once you are talking about
that, you've already lost the war.

JGM

[Hallerb]

>
>
>Are you talking about repair on-orbit? Because once you are talking about
>that, you've already lost the war.
>
>JGM

Isnt it time for a redeign for more durability?