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I think that if the space suit was specially designed for protecting the wearer during re entry into Earths atmosphere, (making the space suit essentially a space craft!)
So how fast would someone travel, at peak velocity, falling from space towards Earth? I had heard claims of speeds exceeding 20 miles a second. Obviously you would accelerate to a very high speed due to the thin atmosphere and then decelerate again as the atmosphere increased in density. What does everyone think?Chris
An approximate rule-of-thumb used by heat shield designers for estimating peak shock layer temperature is to assume the air temperature in kelvins to be equal to the entry speed in meters per second. For example, a spacecraft entering the atmosphere at 7.8 km/s would experience a peak shock layer temperature of 7800 K. This method of estimation is a mathematical accident and a consequence of peak heat flux for terrestrial entry typically occurring around 60 km altitude.
No idea on that one, Chris. But, the fastest freefall to date is 614 mph from 102,800 feet by Joseph Kittinger.
it's been done from 31km back in 1960 by Captain Joe Kittinger of the USAF, he jumped from a balloon, reached a maximum of 988km/h, which gets you as warm as a supersonic aircraft, at high altitude.
31km is still in the stratosphere and we claim 100km to be the legal beginning of space.
Also, if you can fall 31Km and get away with it then, if you fall at the same speed, you can dissipate the same power falling from 100Km. There might be problems with heat soaking through insulation but you only need roughly 3 times the thickness and you should be OK.
I don't think a space suit on its own could do it but I think a parachutist ought to be able to survive.The heat that you have to lose comes from the potential energy you have from being so far up. At 100Km for a 100Kg spaceman and his kit (air bottles etc) you have M *g*h = about 100*10*100000 =100MJ of energy.Imagine a big parachute that will slow you down so it takes a million seconds to fall (OK that's absurd because it's a week or two). At that rate you would have to dissipate 100W of power as heat. People generate about that much heat metabolocally so that would be no problem.If you make the 'chute smaller so the person falls faster the mean power you need to dissipate gets higher- the question is how much can you get away with and how slowly can you fall. Another factor is that most of the heat would be dissipated by the parachute rather than you.
I realise that it would need to be a big 'chute- particularly in the outer atmosphere. I was just pointing out that, in principle, it can be done.
I was going to add, there is another issue I can see here. Since these ultra-big chutes are not going to be usable in the lower atmosphere, the parachutist would probably have to discard it, and deploy a second chute. Since this ultra big chute is going to be too big to burn up in the atmosphere, it holds the potential to remain a long term liability in the upper atmosphere. How would this be addressed? Even if one looks to have the chute disintegrate under UV light, that will still take some finite time, and you then have to concern yourself with how the breakdown products would affect the upper atmosphere.
ammmm.... i dont think that the astronaut cant travel in space if he got stuck there. and supposingly he managed to move towards earth so his spacesuite will definanety burned. you know that if only a tiny pebble will srtike his spacesuite so it will pass through it. so imagine how will his suite can tolerate this much temp. due to friction force of earth's atmosphere if an big meteorite got evaporated.(hey if something is wrong so tell me i'm new here from india)