This is a hypothetical situation since I am not even sure it is possible to do, but work with me on this.
A pilot is zipping along the upper reaches of Earth’s atmosphere. His plane has massive engine failure. His only choices are stay in the plane and die or eject and try to parachute to earth.
His ejection would send him into really, really thin layers of atmosphere. Upon being pulled back to Earth, would he experience any heat upon re-entry? Would it be enough to burn him?
Assuming he survives that first part, does he then have any hope of surviving the rest of the fall or would it be too much of a distance for him to live?
My guess is that he’d black out from lack of oxygen. Hopefully his parachute opens automatically at a certain altitude. If so, and the landing goes smoothly, he might be ok, depending how long he was deprived of oxygen.
If he ejects and the parachute opens automatically (right when he ejects), I’d wager that he’d have some pretty serious brain damage if he survived. Everest is only 29,000 feet up, and they have to use oxygen.
To begin with if he’s in an airplane there is no reentry because it’s already in the atmosphere. The only historical exceptions to this were rocket planes like the X-15 that actually went into suborbital space and rocket assisted jets like the NF-104 that went up to about 104,000 feet. In both instances these planes weren’t flying like an airplane at such high altitude but in a ballistic trajectory like a cannonball.
Second point is why is he doomed to death to stay with the airplane witn an engine failure? How do you think the X-15 and space shuttle orbiter get down, they glide. The NF-104 had to be flown dead stick from the time the rocket engine used up its oxygen until it reached dense enough atmosphere to restart the jet engine. Both engines used the same fuel supply so it never actually runs out of fuel.
Third is you don’t fly at 100k feet in shirtsleeves. X-15 and SR-71 pilots wear what is basically a spacesuits. NF-104 pilots wore a pressure suit similar to that worn by the Mercury astronauts. You’d need an oxygen supply of course but Joe Kittinger survived a parachute jump from extreme altitude that way. The only problem I’m aware of was a swollen hand caused by a glove failure.
Any plane that routinely “zips along in the upper reaches of the Earth’s atmosphere” (e.g., the SR-71) has a separate O2 supply in the ejection seat for the pilot. Also, re-entry would not be a problem. Colonel Joseph Kittenger made a parachute jump from 102,800 feet, well above the SR-71’s operating altitude of 85,000 - 90,000 feet.
On preview, I see Padeye has already posted some of this, but I think there’s some additional information here.
Don’t confuse the heat of re-entry with a spacecraft to just anybody flying really high.
A returning spacecraft is travelling at something like 17,000 MPH or along those lines (think Mach 25 and you get the idea of the speed). All that energy has to go somewhere when it comes back into the atmosphere, hence the heat.