MindStalker: I hope your kidding, he was floating in a balloon with 0 relative surface velocity. Do you have any idea the speeds that the ISS is orbiting at? We don't have a suit that would survive re-entry at orbital velocities.

Odoriferous Queef: dittybopper: Actually, if it came down to it, we could probably man-rate the Dragon spacecraft from SpaceX rather quickly, because pretty much all the development is done already and it has already flown (unmanned) to the ISS, at least until the Orion spacecraft comes on line.

The Ares launch vehicle for Orion has been cancelled.

MindStalker: dittybopper: MindStalker: I hope your kidding, he was floating in a balloon with 0 relative surface velocity. Do you have any idea the speeds that the ISS is orbiting at? We don't have a suit that would survive re-entry at orbital velocities.

Actually, we *COULD* do that:   Paracone

I would expect that with modern materials, it would be even easier to do today, and the system could be packed into a smaller undeployed volume.  Seems to me that would be something we could gin up and test relatively cheaply (by spaceflight standards), and it would make a decent back-up emergency evacuation method.  Not something you'd do as a matter of course, but if you had no other choice.

"No parachute was required. The terminal velocity of the Paracone was 42 km/hour and impact was absorbed by the crushable structure of the cap of the cone.  "

Oh that cute. I'm sure a modern replacement would include a parachute. But a lithobraking manuever isn't exactly optimal for safety.

Mr. Oizo: dittybopper: MindStalker: dittybopper: MindStalker: I hope your kidding, he was floating in a balloon with 0 relative surface velocity. Do you have any idea the speeds that the ISS is orbiting at? We don't have a suit that would survive re-entry at orbital velocities.

Actually, we *COULD* do that:   Paracone

I would expect that with modern materials, it would be even easier to do today, and the system could be packed into a smaller undeployed volume.  Seems to me that would be something we could gin up and test relatively cheaply (by spaceflight standards), and it would make a decent back-up emergency evacuation method.  Not something you'd do as a matter of course, but if you had no other choice.

"No parachute was required. The terminal velocity of the Paracone was 42 km/hour and impact was absorbed by the crushable structure of the cap of the cone.  "

Oh that cute. I'm sure a modern replacement would include a parachute. But a lithobraking manuever isn't exactly optimal for safety.

Well, like I said, it's the sort of thing you'd do if you had no other choice.

And 42 km/hour is about the same as a fall from a 7 meters height, or about 22 feet, with the shock partly absorbed by the structure, and the rest of it evenly distributed across your body.

Sounds eminently survivable to me.  After all, people generally don't die in car crashes where the combined velocity is 26 MPH.


That would be the terminal velocity once back in the atmosphere, where the drag force equals gravity.  Before you hit the atmosphere, however, there is no drag force, therefore terminal velocity is pretty much as high as you have time to fall.

<high school physics>
The ISS height is currently 370 km, or 370,000 m.  Felix "brass balls" Baumgartner jumped out of his balloon just shy of 39 km, and was pretty much in zero drag free-fall for the first 7 km (have a look at the 0:47 s mark of this: http://www.youtube.com/watch?v=raiFrxbHxV0 -- the first derivative of his velocity has stopped being constant, indicative of a deceleration due to the start of air resistance.)   From this, one could assume a jumper from the ISS would be in zero air resistance for 370 - (39 - 7) = 338 km.  Because there is no air resistance, the acceleration is constant: 9.81 m/s^2 no matter how large a parachute you have.  Therefore the velocity attained at the end of the 338 km zero air resistance free fall would be 2,575 m/s (v = sqrt(2da)) or around 5,800 miles an hour.  You'd be entering the atmosphere at Mach 9, with 32 km remaining before slamming into the ground.   At that speed, you'd need to decelerate at over 100 m/s^2 to reach zero velocity before reaching ground level -- that is over 10 g's of vertical deceleration acting on your body.

And that's neglecting the much higher, 17,000+ mile per hour horizontal velocity of the ISS.  Tossing in that 7,700 m/s horizontal velocity, the total velocity when you hit the top of the atmosphere would be over 8,100 m/s, or 18,000+ miles an hour.  Mach 27.  Felix was going at Mach 1 at the same point of the atmosphere (the 0:47s mark of the video above.)  You can see his suit start to blow in the wind at that point of the video -- prior to that there's no wind so nothing for his suit to flap against.  Now consider that wind is rushing past you 27 times faster than seen in the video.  It would tear the suit right off you, and the skin right off your flesh, and the flesh right off your bones.  And your bones would incinerate.  With 10 g's of force in the veritcal direction.
</high school physics>

No thanks.

Mr. Oizo: It's not a question of density of the spacecraft, but of the density of the atmosphere.  Because atmospheric density above 50 km is one thousandth of that of the surface, and at 100 km is one millionth  there's virtually no drag, and during free-fall through space above the Karaman line, you'll be accelerating to ludicrous speed -- if not plaid -- by the time you slam into the thicker part of the atmosphere.  There is a reason re-entry vehicles have high tech thermal shielding, and when just a few of Colombia's thermal blocks failed, the entire spacecraft was lost.