Hi Tom

Yeah I'd read that ballistic re-entries hit some mean gees. Galileo's Jupiter entry maxxed at 450 gee I think. Earth return is supposed to hit ~ 40 gee or so. I think 17 gee is the highest anyone has hit for a sustained time and it was brutal.

I can just rough guess the stagnation zone temp from the amount of energy being dissipated over the re-entry vehicle's leading surface. Apollo 11 came hit re-entry interface at 11,032 m/s, and hit a max-gee of 6.35. It massed 5475 kg and the blunt end was 12.01 sq.m. Hence the absolute peak energy dissipated in heating the shockwave was 3.76 gigawatts - less than that in actual fact, of course. That's 313 megawatts/sq.metre or 8,620 K - according to Gary about 90% or so of the heat is carried away by the gas flow fortunately. Taking that as gospel means a temp of ~ 4850 K on the shield. No wonder it ablated.

FYI Apollo hit max-gee at ~ 180,000 ft, about 90 seconds after entry interface at 400,000 ft and had travelled about 500 nautical miles. Then it kind of flew level about 700 n.miles as it deccelerated, making a few little hops of about 30-40,000 ft max vertical displacement. 4 1/2 minutes after max gee they hit the second peak at ~ 120,000 ft before virtually falling straight down under their chutes.

Wild ride! Hopefully Branson's Virgin Galactic guests will get a smoother ride.

Adam