Stack Exchange Network

Stack Exchange network consists of 174 Q&A communities including Stack Overflow, the largest, most trusted online community for developers to learn, share their knowledge, and build their careers.

Visit Stack Exchange

Questions tagged [karman-line]

The Karman Line (named for Theodore von Kármán) represents the accepted boundary between Earth's atmosphere and space exists (100km). Use this tag to discuss the line and questions about its application

-3
votes
0answers
40 views

Can the question below ignore the acceleration downwards to the centre of the Earth? [on hold]

The question "What would a "Kármán plane" look like, a bird, or a plane ?" clearly ignores the acceleration downwards to the centre of the Earth. The lift force for an airplane is: $$ F_L = 0.5 \rho ...
-3
votes
0answers
65 views

Can the centrifugal force still be ignored as the lift force is a small fraction of the gravitational force at the Kármán line altitude? [duplicate]

The lift force for an airplane is: $$ F_L = 0.5 \rho v^2 S C_L $$ According to this talk page the lift coefficient for a supersonic airplane is: $$ C_L = \frac{4\alpha}{\sqrt{M^2-1}} $$ where $\...
10
votes
3answers
1k views

What would a “Kármán plane” look like, a bird, or a plane?

If I understand correctly (which I might not), the Kármán line is roughly the altitude where a "Kármán plane's" upward lift force at the orbital velocity for that altitude would be equal in magnitude ...
2
votes
3answers
203 views

Is the equation showed below the right one for an airplane flying at the Kármán line altitude?

$$\frac{GM_Em}{(R + h)^2} - \frac{ \rho v^2 S C_L}{2} = \frac{mv^2}{R + h}$$ $GM_E$ is Earth's standard gravitational parameter , $R$ is Earth's radius and $h$ the altitude of the airplane above the ...
1
vote
2answers
84 views

Could the $C_L$ of the X-15 be calculated from the flight data near the Kármán line altitude?

The "lift coefficient" $C_L$ can be very different for one specific aircraft at different speeds. According to this article from NASA about the lift coefficient: So it is completely incorrect to ...
-3
votes
1answer
93 views

Does an airplane in orbit near the Kármán line altitude, with the air providing lift, ever reach orbital velocity? [duplicate]

The equation for an airplane in orbit with the air providing lift would be: $$\frac{GM_Em}{(R+h)^2} - \frac{\rho(h) v^2 S C_L}{2} = \frac{mv^2}{R+h} $$ $GM_E$ is Earth's standard gravitational ...
-4
votes
1answer
135 views

Where does the definition of the Kármán line on Wikipedia come from?

According to Wikipedia's article about the Kármán line: The Kármán line is the altitude where the speed necessary to aerodynamically support the airplane's full weight equals orbital velocity ( ...
4
votes
0answers
110 views

Are there calculations regarding the Kármán line in the Theodore von Kármán collection?

According to this article, page 673: The "von Kármán line" appears to be what mathematicians refer to as a "folk theorem" , arising out of a conference discussion but never formally published by ...
-1
votes
2answers
115 views

What physical ways can the Kármán line be used? [closed]

I have also seen many posts on this. I understand what the line is used for legally. The Kármán plane or a plane that is most efficient at the line regardless of the shape seems not to have a specific ...
-2
votes
1answer
103 views

Is it correct to apply the vis-viva equation to an airplane that flies in a straight line at the Kármán line?

The vis-viva equation models the motion of an orbiting body and it applies when the only force acting on the body is it's own weight. So is it correct to apply this equation to an airplane that ...
-6
votes
1answer
138 views

Does a credible Kármán plane reach escape velocity within 1 minute or does it follow the curvature of the Earth? [duplicate]

Edit: This question is no duplicate because here the dropping of the atmospheric density together with the horizontal line, play an important role. Furthermore none of the answers and question ...
10
votes
1answer
216 views

What did Karman's original “Karman line” calculations look like?

Looking for the atmospheric parameters (density for example) and vehicle parameters (CL for example) as well as formulae that were used in the original calculation. Primary sources strongly preferred,...
0
votes
1answer
92 views

Is a Kármán Rocket Possible? [duplicate]

Why are the rockets not razor sharp, skinnier and taper off at both ends farther to cut through air better? Would making a rocket more aerodynamic allow it to be more efficient flying as a "Kármán ...
-3
votes
2answers
219 views

Can it be calculated that near the Kármán line the lifting force equals the centrifugal force?

According to Wikipedia about the Kármán line: In the final chapter of his autobiography Kármán adresses the issue of the edge of outer space: ...or 24 miles up. At this altitude and speed, ...
0
votes
2answers
77 views

Is it correct to use the vis-viva equation when there are two forces acting on the orbiting body? [closed]

Edit: Although this question seems similar to the question "Is it correct to apply the vis-viva equation to an airplane that flies in a straight line", it is different because there the airplane flies ...
7
votes
1answer
189 views

Why is FAI considering lowering the Karman Line to 80km?

I ran across this FAI statement The Karman line is the 100km altitude used by FAI and many other organisations to mark the “boundary” of space . In the last few years there have been many ...
43
votes
5answers
9k views

Where does space begin on planets without atmospheres?

On Earth the Karman Line is used as the boundary of space, and I believe it is defined as the height where you would have to go faster than orbital speed in order to obtain aerodynamic lift. Therefore ...
7
votes
1answer
92 views

What is the practical use of the Karman line?

There have been several questions recently about the details of the definition of the Karman Line and the history of those calculations. This is not about those issues. The question is: In practical,...
1
vote
1answer
76 views

At what conference the “von Kármán line” arose and was discussed for the first time?

From this article on page 673: The "von Kármán line" appears to be what mathematicians refer to as a "folk theorum", arising out of a conference discussion but never formally published by him. It ...
-6
votes
2answers
472 views

Is the definition of the Kármán line from Wikipedia right? [closed]

Edit: this question is about making clear that the Wikipedia's article about the Kármán line is an interpretation, not the definition ! Why not consider the Kármán line as a curved boundary that ...
6
votes
1answer
213 views

Did the Soviet Union put an unmanned satellite in “very low orbit”above the Kármán line which used aerodynamic attitude control?

This interesting, archived page https://www.webcitation.org/618QHms8h?url=http://www.fai.org/astronautics/100km.asp which I found in this answer, says: Later in the same decade (or very early in ...
31
votes
2answers
6k views

How did the X-15 control attitude above the Kármán line?

This interesting, archived page https://www.webcitation.org/618QHms8h?url=http://www.fai.org/astronautics/100km.asp which I found in this answer, says: In the early 1960´s, the U.S. X-15 Aircraft ...
3
votes
0answers
48 views

what is the relevance of ion cyclotron and ion collision frequency ratio

On earth, the ion cyclotron and ion collision frequency ratio is 1 at roughly 118 km, and this is used as one of the definitions of the limit to space. What are ion cyclotron frequency and ion ...