[hopespringseternal]

And replace the heat-shield system with WHAT exactly?

On the next vehicle, use carbon-carbon for the really hot spots and titanium elsewhere.

Given the amount of preliminary work done, I can't fathom why they need three years just to make a decision.

[_Jim]

On the next vehicle, use carbon-carbon

What if - what if I told you they use carbon-carbon already?

Hmmm?

[_Jim]

RCC is, BTW, no substitute for insulation of some sort, so, you still need to come up with what might be called the system solution that also meets the requirements for light-weight in the design goal ...

From the Space Shuttle handbook:

The RCC panels are mechanically attached to the wing with a series of floating joints to reduce loading on the panels caused by wing deflections. The seal between each wing leading edge panel is referred to as a T-seal. The T-seals allow for lateral motion and thermal expansion differences between the RCC and the orbiter wing. In addition, they prevent the direct flow of hot boundary layer gases into the wing leading edge cavity during entry. The T-seals are constructed of RCC.

Since carbon is a good thermal conductor, the adjacent aluminum and the metallic attachments must be protected from exceeding temperature limits by internal insulation. Inconel 718 and A-286 fittings are bolted to flanges on the RCC components and are attached to the aluminum wing spars and nose bulkhead. Inconel-covered cerachrome insulation protects the metallic attach fittings and spar from the heat radiated from the inside surface of the RCC wing panels.

The nose cap thermal insulation ues a blanket made from ceramic fibers and filled with silica fibers. HRSI or FRCI tiles are used to protect the forward fuselage from the heat radiated from the hot inside surface of the RCC.