Space Diving

[mjbaldwin]

I sent Cecil the following message and it came back with a nice reply suggesting I ask here, since they wouldn’t be answering it. So, curious if anybody had any ideas?

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Dear Cecil:

I’m reading today about the possible damage to the space shuttle, and how it could lead to an explosion during descent. Which leads me to the question: would it be possible to sky-dive (or, in this case, space-dive) down to Earth? As long as the astronauts were wearing pressurized space suits with oxygen supplies, would they be able to make it down to Earth OK? (Forgetting for a moment the difficulty of choosing where to land.) I know things burn up in the atmosphere when entering at high speeds, but normal skydivers reach terminal velocity and they don’t burn up! I suppose the main question regards how much friction is produced as one enters the atmosphere and one’s terminal velocity reduces accordingly.

[Exapno_Mapcase]

Terminal velocity is about 144 mph. Return speeds from space are about 17,000 mph. That’s the problem in a nutshell.

[msmith537]

@mjbaldwin

I know things burn up in the atmosphere when entering at high speeds, but normal skydivers reach terminal velocity and they don’t burn up! I suppose the main question regards how much friction is produced as one enters the atmosphere and one’s terminal velocity reduces accordingly.

A skydiver starts from 0 mphs (or the aircraft speed) and accellerates to terminal velocity (144mph). Objects in orbit start at 17,000 mph and DEcellerate to terminal velocity.

So the answer to your question is “a lot”.

[Tuckerfan]

NASA thought of the idea about 40 years ago and the solution is called MOOSE

MOOSE was perhaps the most celebrated bail-out from orbit system of the early 1960’s. The suited astronaut would strap the MOOSE to his back, and jump out of the spacecraft or station into free space. Pulling a ripcord would fill an inflatable heat shield with polyurethane. The astronaut would use a small hand-held gas to orient himself for retro-fire, and then fire a solid rocket motor strapped to his chest to return to earth.

The MOOSE consisted of a chest-mounted parachute, a flexible, folded 1.8 m diameter elastomeric heat shield, and a canister of polyurethane foam. Pulling the deployment cord would fill the shield into shape and encase the back of the astronaut in perfectly form-fitting polyurethane. The astronaut would use a small hand-held gas get device to orient himself for retro-fire, and then fire a solid rocket motor mounted in the device. After aligning himself for re-entry and putting the MOOSE into a slow roll, he would throw the gas gun away. After a ballistic re-entry, the astronaut would pull the ripcord of the chest-parachute, which would pull him away from the heat shield for a parachute landing.

[charizard]

To be a little more explicit in the answer, the problem doesn’t come from how *high * they are. Parachuting back from space has essentially already been done.

The problem is that if they’re in orbit they’re also whipping around in a circle at tremendous speeds. That’s what makes it so vicious to hit the atmosphere on the way back.