Red Bull Stratos

[derf]

Originally Posted by Cutty72

At what altitude do you start getting above the atmosphere where there will be a heat issue?

Its not the fact that you are hitting atmosphere, but when something enters earths atmosphere from orbit it is usually travelling at a fairly high rate of speed. Its the high rate of speed vs atmosphere that causes stuff to burn up. In this case he started falling from 0mph and accelerated from there until he hit terminal velocity (maximum speed at which his shape was able to cut through the air), at that point the air would eventually slow him down keeping him at his max velocity.

When something enters from space it is above its max velocity and air slows it down tremendously with heat caused by friction with air molecules being a byproduct.

I asked the same question yesterday and the internet gave me the answer

[Smittie61984]

I see what he was asking. The space shuttle comes out of space at 17,000mph and they start burning up in the mesosphere. (same place meteorites burn up). I believe the burn stops at the stratosphere becuase they have slowed down to mach5 or so.

What I think is cool is that according to the general theory of relativity, a man in space would (where Felix and Kittinger to a degree was) would not feel the rush of free fall until the troposphere with the thicker air.

[Cutty72]

Originally Posted by derf

Its not the fact that you are hitting atmosphere, but when something enters earths atmosphere from orbit it is usually travelling at a fairly high rate of speed. Its the high rate of speed vs atmosphere that causes stuff to burn up. In this case he started falling from 0mph and accelerated from there until he hit terminal velocity (maximum speed at which his shape was able to cut through the air), at that point the air would eventually slow him down keeping him at his max velocity.

When something enters from space it is above its max velocity and air slows it down tremendously with heat caused by friction with air molecules being a byproduct.

I asked the same question yesterday and the internet gave me the answer

The interwebz is awezome.

[Trip]

Originally Posted by Smittie61984

What I think is cool is that according to the general theory of relativity, a man in space would (where Felix and Kittinger to a degree was) would not feel the rush of free fall until the troposphere with the thicker air.

Kittinger has actually talked about this... He said he was scared out of his fucking mind at first because he didn't know if he was falling or not.

[Smittie61984]

Originally Posted by Trip

Kittinger has actually talked about this... He said he was scared out of his fucking mind at first because he didn't know if he was falling or not.

I remember watching an interview of him talking about having to rotate to make sure he was falling. That'd be a scaring feeling at first.

I really hate that Kittinger never really got that much recognition. I believe him to be the first man in space. Almost everything about that altitude screams space except there is gravity to pull him down. If he took off his suit at that height his blood would boil instantly. That's space to me.

[Homeslice]

Originally Posted by Smittie61984

What I think is cool is that according to the general theory of relativity, a man in space would (where Felix and Kittinger to a degree was) would not feel the rush of free fall until the troposphere with the thicker air.

Why wouldn't you? Anytime something causes you to accelerate, you're going to feel it.

[Trip]

Originally Posted by Homeslice

Why wouldn't you? Anytime something causes you to accelerate, you're going to feel it.

hardly any external pressure and basically no friction.

[Smittie61984]

Originally Posted by Homeslice

Why wouldn't you? Anytime something causes you to accelerate, you're going to feel it.

It's hard to demostrate without pictures but we all know F=ma which means the net force is equal to an objects mass times acceleration (acceleration is change in velocity over change in time). A more accurate way to put it is a=Fnet/m.

First off all of this is relative to Felix and not us. To us he is accelerating at roughly -(9.8m/s)/s. To felix though, it's a different story. Think of watching a man standing on a train going 30mph. To the man on the train, he's standing still. To you looking at him on the train, he's going 30mph.

To put it simply, if you skydive, you feel the free fall feeling because you have air molecules pushing against you and you are pushing against air molecules. The force your exert on the air molecules is greater than what they exert on you so you accelerate and you feel it.

For Felix, he isn't pushing against any air molecules and there aren't any air molecules pushing against him. The net force relative to him is practically 0. a=Fnet/m=0/m=0. Relative to Felix he doesn't notice acceleration.

[VatorMan]

[derf]

Originally Posted by Homeslice

Why wouldn't you? Anytime something causes you to accelerate, you're going to feel it.

Originally Posted by Trip

hardly any external pressure and basically no friction.

You wont know you are falling unless you feel the sensation of air across skin or have a visual reference that you are falling. If you jump out of a window you will know you are falling because you see the ground getting closer, you might get a second or two of rushing air but that really it. Jumping out of a plane is similar, but you dont get as good of a sense of distance until you are pretty close to hitting, but you will feel the wind rushing past your skin.

In this case since he was so high up and encased in a space suit he had neither. He would have eventually noticed that he was getting closer to the earth but it would have taken so long, and been such a gradual process that it would be hard to notice.

A good comparison is the zeroG flights, really while it looks like they are flying, they are actually falling inside of a plane which is loosing altitude at the correct angle and speed so as to mimic zero gravity. The people inside the plane without a visual reference or physical cue only know that they are floating, but have no idea how fast they are actually falling.

http://www.youtube.com/watch?v=S2VLyX80eXs