Assume somebody was unaffected by vacuum, and tumbled out of an orbiting space shuttle. What physical characteristics would their body have to possess to not get burned up on re-entry? Does a person’s volume generate enough of a pressure zone to even reach high temperatures? ?
Not an exact answer to your question, but here’s an interesting article about various bail-out schemes for astronauts:
http://www.astronautix.com/craftfam/rescue.htm
I particuarily like MOOSE - barely more than an ejection seat with a heatshield on the back!
THere is a re-entry buble that was theorized - maybe a prototype was made.
YOu climb into an inflated bubble - the ship/station you are on pushed the bubble out of orbit and the bubble lands you safely on the earth some time later. The plactic shell (IIRC) was coated with some heat shilding ablative material.
There’s a problem; if you jumped out of the orbiting shuttle, you wouldn’t fall to Earth, but would continue in orbit around it in much the same path as the shuttle.
Even if the astronaut jumped straight down in the direction of the earth? I’ll admit my orbital mechanics aren’t the best, but such a jump would place the astronaut in a slow descending spiral of an orbit, would it not?
you would have to be a guy who has taken more than a million doses of steroids. Similar to a water buffalo. i’m betting that you would need more boost on your way down to quicken the speed you are falling so you won’t burn as much - and no resistance, means you’d have to be shaped like a cone.
what a dumb answer…
I wasn’t replying so much to the OP but to Mangetout’s assertion that someone jumping from the shuttle wouldn’t fall to earth, but stay in the same orbit as the shuttle.
If you are in a stable orbit, you need to kill some of your orbital speed so you go into a lower orbit. If the new orbit is low enough, it will intersect with the earth’s atmosphere and the air friction will bring you all the way down. On the Shuttle, the engines slow down the Shuttle by 300 feet per second. So if you want to abandon ship and escape, that’s how fast you need to jump off the Shuttle.
Note that 300 fps is about 1% of the orbital speed. You still hit the atmosphere at 7 km/s. You have about two billion Joules of kinetic energy, which will all turn into heat by friction. If the heating takes 10 minutes, you’re dealing with 3 million Watts of heat.
So the answer to the OP is that you need an engine that can accelerate (or decelerate) you by 100 meters per second, a heat shield that can withstand 3 million Watts for 10 minutes, and a method for slowing down the final impact with the ground. You also need the heat shield on all sides, or a method to keep the heat shield pointing forward. Currently the cheapest such escape system is the Soyuz capsule, and a couple of them are docked on the International Space Station for that very purpose.
A very slow reentry velocity to negate the heat generated by atmospheric friction, and some specially designed parachutes like those used by participants in the USAF’s “Man-high Project”.
Oh, and a place to land.
In order to do a “very slow reentry,” you have to first use an engine to kill your orbital speed. In general, such an engine will be more expensive, less reliable, and heavier than a heat shield.
This is true.
If you jumped from the shuttle towards the Earth, you wouldn’t be in a lower orbit really, but an elliptical orbit. A quarter rotation away, you’d hit a minimum height above the Earth, then you’d start going back towards the shuttle. On the other side of the Earth, you’d pass the shuttle and go higher than it.
If you jumped backwards from the shuttle (on its path around the Earth, but in the opposite direction), you’d hit a minimum altitude half way around the Earth, but then come back to the same altitude after one complete revolution. But in this case, I think you’d actually be ahead of the shuttle! Can any rocket scientists check to see if this is right?
As far as I know, Julie Andrews is the only person on Earth who has done this successfully.