Re: Would 'double hull' help?

[Terrence Daniels]

> The 2nd layer would need to be much stronger (heavier?)

Effectively, they're the same thing.

b/c, AIUI, the plasma
> is "channelled" through the hole and becomes even hotter.

That's how I understand it also... Any sort of turbulent flow there and the
heat problem is even worse.

How would you design for that? What's the margin of safety you're looking
for? Realistically you'd be adding a whole load of extra weight for an
unknown contingency, which in itself would be caused by something that
shouldn't have been happening in the first place.

I'm not saying they shouldn't look at ways to toughen up the RCC, but I
think double-hulling would impose too many penalties in work, materials, and
weight for too little gain.

[Brian Gaff]

"Buck" > wrote in message
.161...
| Presuming that there is no realistic and reasonable fix for foam
| shedding, what about a 'double hull' approach to the leading edge? I'm
| thinking about another RCC layer set back a foot or two. FOD damages
| the front layer and sprays low velocity debris inside the cavity between
| the first and second layers of RCC. Plasma enters the first cavity but
| is resisted by the second.
|
| Issues of added weight and aerodynamic problems with a leading edge
| breach remain, and might render such an idea moot. This also doesn't
| help a breach in the tiles (especially around the wheel well), but it
| appears that the tile is somewhat more rugged than the RCC.
|
| --buck
I'd have thought a sandwich construction of rcc, tile material, something
else on the inside might have a better chance of survival. It is probably
the brittle nature of the current material that has caused the problem.

You might be able to have a slightly less thick piece of the carbon
material, then tile material, then some metal on the inside.

Just a thought.

Brian

--
Brian Gaff....
graphics are great, but the blind can't hear them
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[magnetogorsk]

Any weight put into a 'double hull' would seem to be much better spent
beefing up the main protection instead.

But in any event a redesign this major would mean an entirely new design.
And if you are designing from scratch, why not actually design something
good? The orbiter is basically a flawed compromise, designed, among other
things, to fulfil the Air Force's requirement for high-cross range
capability (i.e., the ability to glide a long way). This capability has
never really been needed and is completely non-essential.

But not only is it non-essential. It is, in fact, positively detrimental to
shuttle safety. The high thermal loading imposed on the shuttle by this
re-entry profile has resulted in half of the major problems in the shuttle
program.

If you were to design a new, re-usable spacecraft (although that might not
be a good idea in and of itself), it would be wise to learn from the failure
that is the SSO program. Meaning:

1. No solid fuel boosters. You need liquid fuel anyway, so there is no point
complicating your design with an entirely separate and different rocket
design to go along for the ride.

2. Short re-entry. The ability to fly to an alternate landing field sounds
great on paper. But you never do it. It's not going to happen. Forget about
it. If something goes wrong, the rocket blows up and you are all dead.
You're not going to fly your way out of it. That's the biz, sweetheart. If
the capability were free, then of course it would be worth having. But
nothing is free in rocket science. Adding weight to glide with makes
everything else LESS safe.

3. More engines. The Orbiter engines are overworked. Solution: Add two more
of them.

4. Tank on top of orbiter? Without SRBs, I think the External Tank should
fit on the front and around the nose of the redesigned orbiter. This is a
longer stack and an interesting structural problem, but overall it is
probably cleanest from a standpoint of vibration and exhaust problems.

"Terrence Daniels" > wrote in
message hlink.net...
> > The 2nd layer would need to be much stronger (heavier?)
>
> Effectively, they're the same thing.
>
> b/c, AIUI, the plasma
> > is "channelled" through the hole and becomes even hotter.
>
> That's how I understand it also... Any sort of turbulent flow there and
the
> heat problem is even worse.
>
> How would you design for that? What's the margin of safety you're looking
> for? Realistically you'd be adding a whole load of extra weight for an
> unknown contingency, which in itself would be caused by something that
> shouldn't have been happening in the first place.
>
> I'm not saying they shouldn't look at ways to toughen up the RCC, but I
> think double-hulling would impose too many penalties in work, materials,
and
> weight for too little gain.
>
>