Cavity behind the RCC leading edge

This issue has been raised several times during the past 6 months. There is
a fairly large class of space-qualified materials that could be used to
protect the aluminum wing spar behind the RCC parts. They're called ablators
and have been used since the dawn of the Space Age as rugged TPS (i.e. heat
shields). My current favorite is a NASA-Ames product called Silicone
Impregnated Reusable Ceramic Ablator (SIRCA), but there are a half dozen
other ablator materials that could be used. For example, Teflon is an
excellent ablator, but is fairly dense (130 pounds per cubic foot). A
1-inch-thick slab of Teflon between the RCC and the aluminum spar would
probably add about 3,000 pounds to the orbiter weight. NASA undoubtedly
would reject Teflon on this basis since the orbiter right now has to
struggle mightly to get the heavier ISS parts up to the construction orbit
(~200 nmi altitude). SIRCA at about 30 pounds per cubic foot looks more
promising.

Later
Ray Schmitt



"jay" wrote in message
66...
"Chuck Stewart" wrote in
news
On Mon, 01 Sep 2003 02:52:22 +0000, Derek Lyons wrote:

"Paul F. Dietz" wrote:

Chuck Stewart wrote:

And any "foam" behind [the RCC] would
conduct the heat even faster than the void that is currently behind
the leading edges.

greetings...

It seems to me that if the leading edge had some physical backup, it might
withstand abuse a bit better.
I wonder if the ceramic tile material would work? Use the rcc outer, with
tile underneath?
Certainly it would be damaged by a major strike, but might still bring the
bird home...

That carbon aerogel sounds like great stuff, but I ddin't see structural
data on it. (ok, didn't look that hard)

It seems to me, that a big thing is to prevent any plasma leakage from
penetrating the main wing. Maybe the carbon aerogel would slow the flow
and
diffuse it enough to keep things alive?
regards
Jay