That was the point of my post. Even with what we had, it wasn't enough, and it still required "active cooling" of pumping slush H2 through the wings and fuselage.
> That was the point of my post.
Ah. In post 18 you seem to be suggesting that the Shuttle leading edge was originally far heavier. It's the actively cooled hypersonic structures that tend towards massive heaviness, rather than radiatively cooled structures like the Shuttle leading edge.
There are annoyingly good reasons why hypersonic aircraft are a wee bit of a rarity.