Do you have a source? My understanding is that the skin is the pressure vessel. The reason for going with stainless steel at all is because it maintains integr

Do you have a source? My understanding is that the skin is the pressure vessel. The reason for going with stainless steel at all is because it maintains integrity at high temperature. Carbon fiber does not. So a stainless steel combined heatsink and structure can maintain integrity at 1000C or whatever, while carbon fiber+ceramic heatshield will need to hold temperatures below 400C or whatever. And even though the fiber structure is much, much lighter, the amount of heat protection required is massive. And the stainless steel "cheats" by performing double duty. And you get a second free lunch because the heat protection requirements are slimmer. It wouldn't be the first time I've been wrong today though. Nor the second.