wardialer
Posts: 1140
Joined: Fri Sep 14, 2001 1:08 pm

What Is The Edge Of Space (Altitude In Feet)

Tue Oct 01, 2002 2:27 am

At about what altitude does actual space begin in feet? I heard it was something like 350,000 feet. But I just want to make sure.
 
bragi
Posts: 212
Joined: Sun May 27, 2001 5:17 am

RE: What Is The Edge Of Space (Altitude In Feet)

Tue Oct 01, 2002 3:20 am

Hi,
I hope this is helpful:
The atmosphere is divided into; the troposphere (approx. 36.000 feet, where most of the flying takes place), the stratosphere (approx. 164.000 feet), the Mesosphere (approx. 262.000 feet) and the ionosphere, which is divided into four layers and extends to about 700 kilometers. That´s approx. 2296700 Feet.

When you leave the ionosphere, you´re out of the atmosphere!
Muhammad Ali: "Superman don’t need no seat belt." Flight Attendant: "Superman don’t need no airplane, either."
 
sllevin
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Joined: Wed Jan 30, 2002 1:57 pm

RE: What Is The Edge Of Space (Altitude In Feet)

Tue Oct 01, 2002 3:24 am

For what's it's worth, the USAF and NASA consider a person to be an astronaut if they've flown higher than 264,000 feet (50 miles). This was most relevant to people flying the X-15, which was capable of getting above that altitude.

Steve
 
jhooper
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RE: What Is The Edge Of Space (Altitude In Feet)

Tue Oct 01, 2002 11:10 am

While there might be various definitions, I don't believe that there is an exact point where atmosphere stops and space starts. The further away from earth you get, the less air molecules you will encounter, but it's a gradual transition. Perhaps someone can answer at what altitude does the sky lose it's blueness and turn black? That's where I tend to define "space".
Last year 1,944 New Yorkers saw something and said something.
 
sllevin
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Joined: Wed Jan 30, 2002 1:57 pm

RE: What Is The Edge Of Space (Altitude In Feet)

Tue Oct 01, 2002 1:59 pm

Seeing "black" and the curvature of the earth happens while one is still well within what I think we'd define as 'atmosphere' -- somewhere around 60,000 feet or so. Concorde sees it, and the XB-70 and SR-71 pilots saw it as well in the 70,000 foot range. But there's still plenty of atmosphere at that point -- enough to heat their airframes to nearly 1000 degrees Fahrenheit in the case of the SR-71!

But yes, even at 50 miles it would be tough to maintain an orbital profile, but the decay would be in tens of hours, though. The shuttle routinely operates in at the 150mile arc, though.

Steve
 
ThirtyEcho
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RE: What Is The Edge Of Space (Altitude In Feet)

Tue Oct 01, 2002 2:41 pm

Physiological "space" is what counts. That is where, without a pressure suit and pressurized oxygen helmet, your blood would boil instantly in a depressurization and you would be immediately dead. Depending on atmospherics, that altitude is around 60,000 feet. Virtually all of the atmosphere is below you at 60,000.

Have fun suiting up for your trip on Concorde, heh-heh.
 
prebennorholm
Posts: 6419
Joined: Tue Mar 21, 2000 6:25 am

RE: What Is The Edge Of Space (Altitude In Feet)

Wed Oct 02, 2002 5:15 am

The 50 miles border is in fact a "political" one. Some 40 years ago the USA and the Soviet Union agreed upon recognizing the 50 miles border (or rather 80 km which is approximately 49.7 miles).

I think that that border was later somehow recognized by the UN too.

It means that an unarmed vehicle (e.g. a spy satellite) cruising above that border shall be considered a "legal" vehicle anywhere, while below....

Regards, Preben Norholm
Always keep your number of landings equal to your number of take-offs
 
GDB
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RE: What Is The Edge Of Space (Altitude In Feet)

Thu Oct 03, 2002 1:39 am

Liquids boil at 63,000ft.
Concorde routinely reaches 58,000ft at the top of the cruise/climb.
At 58,000, the sky is a dark blue, with the curvature of the Earth visible in clear conditions, (distortion through camera lenses and windows does tend to exaggerate this in pics taken by pax though).
 
Guest

RE: What Is The Edge Of Space (Altitude In Feet)

Thu Oct 03, 2002 3:31 am

GDB - which liquid - ??? water or mercury, or beer...
xxx
Blood boils at 63,000 feet, at its temperature of 98 F or 37 C...
Reason why pressure suit required to fly at high levels...
xxx
My blood boils too, in view of numerous incorrect statements, at sea level...
(s) Skipper
 
prebennorholm
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RE: What Is The Edge Of Space (Altitude In Feet)

Thu Oct 03, 2002 7:58 am

Lukewarm beer starts boiling off the alcohol slightly above 50,000 ft. So if you want to get blasted on a Concorde trip, then better keep that cabin pressure up or keep your beer cold.

On an unpressurised Concorde I'd recommend whisky on the rocks rather than hot tea.

PS: Only one slight problem - when the alcohol goes into your blood, then how do you keep it cold?
Always keep your number of landings equal to your number of take-offs
 
Guest

RE: What Is The Edge Of Space (Altitude In Feet)

Thu Oct 03, 2002 10:27 am

If this helps... On average, at 100,000ft, 99% of the atmosphere's molecules are below you. But there is still a whole heck of a lot of distance above you too!

Cameron
 
GDB
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RE: What Is The Edge Of Space (Altitude In Feet)

Fri Oct 04, 2002 12:30 am

I was obviously referring to the previous post, which specified blood, but it was late!
Concorde's cabin pressure is some 6000ft.

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