Talk:Kármán line

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Since the FAI uses the term Karman line wouldn't it make sense to create a page to that effect and to redirect one of these to the other?

Ooops, I see that's been done already. JimD 21:24, 2004 Jun 21 (UTC)

The U.S. definition[edit]

Most of the following is copied from Reubenbarton's and my discussion pages:

Reubenbarton, I'm just writing to tell you that I feel it was extremely rude of you to add this change to the Boundary to space article. What I'm fired up about is not as much that I feel that this info doesn't belong there, but the fact that you submitted this as a "minor" change (which it clearly wasn't).

Regarding the Gagarin/FAI statement itself: I don't know whether it's true or not, and frankly, I cannot be <behind>ed to check (any resonable person would consider Gagarin's flight a spaceflight). In any case, this info just doesn't belong in that article. I understand how the preceding paragraph might have prompted you to add it, but it still doesn't belong in that article. Besides, nobody in their right mind would take the reported cynic's claims seriously anyway and the info on it is more of an attempt to refute it than anything else.

And yes, I know I shouldn't get protective of articles I started because I don't own them after submitting, but there you go.

Ropers 20:03, 25 Jul 2004 (UTC)

The sources for the Gagarin statement are:
 The Encyclopedia Astronautica - Vostok 1:

"...Gagarin ejected after reentry and descended under his own parachute, as was planned. However for many years the Soviet Union denied this, because the flight would not have been recognized for various FAI world records unless the pilot had accompanied his craft to a landing."

and the FAI Sporting rules on Astronautics:

"2.12.4 The pilot and crew of an aerospacecraft shall remain inside the vehicle during descent and landing. For spacecraft any method of descent and landing is acceptable provided the method is described in detail in the pre-flight plan."

What is the reference for this statement?

"Some cynics argue that the U.S. definition exists solely for historical reasons, because after the Yuri Gagarin PR disaster the U.S. needed an astronaut, and fast, so they might have decided to lower the bar a bit." Rusty 22:54, 25 Jul 2004 (UTC)

Hm. I noticed that the above FAI pdf is dated 25 April/1 August 2003, so this particular document isn't proof that the Soviets "cheated against FAI rules" (because it doesn't say what the rules were in 1961.) But anyway. Maybe they did, maybe they didn't. This particular issue/clause certainly wouldn't make me consider Gagarin's flight less of a spaceflight. If you've got clear proof then maybe this could... oops, ok, I see you have added this info to the Vostok 1 article. So then I think it can't hurt to back up this change/charge with some bulletproof evidence.
Talking of bulletproof evidence, I don't have such for the paragraph reporting the cynic's view on the U.S. definition. It's just something I heard people say, like, repeatedly over here in Germany. I could of course start looking for proof on the web now, but I cannot be bothered. Again, I didn't mean to have a go at the U.S. To fully quote the related sentences:
Some cynics argue that the U.S. definition exists solely for historical reasons, because after the Yuri Gagarin PR disaster the U.S. needed an astronaut, and fast, so they might have decided to lower the bar a bit. If that were true however, it would have been an unnecessary step: Alan Shepard, the first U.S. astronaut, travelled 185 km (115 miles) up.
Again, my intention was not to slander the US, but to put the cynic's claims into perspective: Alan Shepard travelled 185 km up, which kinda tells something about the aforesaid cynic's interpretation.
All that said, I wouldn't scream murder if the above sentences got removed. It's only vaguely related trivia anyway and doesn't offer hard and fast evidence on how the U.S. definition was arrived at. To play it fair, you could e.g. call a vote (to potentially facilitate which I copied this stuff to/wrote my response (here) at Talk:Boundary to space.)
Ropers 19:48, 26 Jul 2004 (UTC)
No I wouldn't think of changing the statement. You insist on including it and your admission that you can't be bothered looking up facts and to placing POV unsubstantiated statements in the article should stand on their own. These kinds of facts should help readers to decide on the value of the article.Rusty 03:07, 27 Jul 2004 (UTC)
Oh come on! Do you absolutely, positively WANT to believe that I'm "teh enemeh"? Are you so keen on believing that my intention was sinister and not to inform of alternative and/or non-US point of views? Is it so hurtful to you to even learn of the existance of such views? Do you have to shoot at the messenger because you think the messenger agrees with the message? Despite me making it very clear that if anything, the opposite is the case? Listen: I've removed the said sentences. If people want to put them back in, fine, but I'm not going to touch them anymore. I cannot help but feel sorry: It must be really frightening to live with a frame of mind where the world appears to be out to get you. Ropers 18:53, 27 Jul 2004 (UTC)
Just remember, it is not I who have removed a single word from the article. It is you that chose to practice censorship and I didn't make a move to reverse it. I just expressed my views in the discussion page after being attacked and called "rude" for just doing what Wiki is about. You mentioned Gagarin in the edge of space article and so did I. I backed my statement with sources (here are additional sources: Encyclopedia Astronautica, BBC Science page,, and you did not. I ask for a source and get a aspersions and false pity heaped on me. That must mean you don't have a source. I invite you to read the latest version of the Vostok 1 article. I believe it has a neutral POV. It states the facts of the flight. I have also built a timeline of the flight from various internet sources. Have a nice day. Rusty 21:36, 27 Jul 2004 (UTC)
Right. So marking a real change as a minor edit is "doing what Wiki is about"? Are you at all familiar with this Wikipedia policy? And since when does removing off-topic info from a specific article equal censorship? I felt your initial action was rude against the backdrop of accepted Wikipedia policy. You accuse me of practicing censorship based on what? Show me I've behaved badly and I'll apologize. Ropers 13:46, 28 Jul 2004 (UTC)

Boundary of Space[edit]

Wouldn't Boundary of Space make a much better title? I have never heard anyone say "boundary to ________", only "boundary of __________". Besides, it is the boundary of space. Or perhaps if you'd rather the "Boundary of Earth's Atmosphere"? Well, I will let you decide, and perhaps if no one replies I will move it. Moogle 05:41, 30 Sep 2004 (UTC)

Space does not equal orbit[edit]

There has been a tendency to document so-called "common misunderstandings" in these space and orbit related pages on Wikipedia. For every fact, it seems to me, there are a hundred possible misunderstandings. We are having enough difficulty documenting the facts, nevermind supposedly "common" misunderstandings. This is not supposed to be an encyclopedia of common misunderstandings.

But even if it were, the "common misunderstanding" documented in this article, that "space does not equal orbit" is not "common" in my experience. I have never, ever heard or read that reaching space was misunderstood as reaching orbit. I think possibly what is happening is that an editor (or editors, but I think there is only one) is documenting his own misunderstanding or the misunderstandings of a colleague or family member.

It also seems to me that a "common misunderstanding" which can be resolved by simply referring to a dictionary should rarely, if ever, be documented here for the well established reason thet Wikipedia is not a dictionary: We do not provide dictionary definitions. Nobody who is prepared to refer to a dictionary could confuse entering space with performing an orbit.

We must provide encyclopaedic articles on both Earth orbit and this subject, the boundary to space. That some may confuse the two is no more likely than many other confusions. If there are 1000 distinct, unrelated facts then 1,000,000 false connections between them could possibly be arrived at by the ignorant. We can document the 1000 facts not the 1,000,000 false connections: We cannot hope to double guess the wilfully ignorant by deciding which of the 1,000,000 possible misconceptions we must debunk.

Were I to trawl through Wikipedia recording all of my previous misconceptions I would create a lot of useless noise and annoyance, even if I just did the ones I felt were common. F'rinstance: I once thought, a long time ago, that Spain was the capital of France. Once of my other childish misunderstandings but apparently one which is fairly common was that you see in a radar-like fashion by emiting a beam from one's eyes. In a similar theme I also was convinced, as are many, that electricity travelled outbound along the red wire and the black wire until it met at the lightbulb where the collision caused the light. And a more serious misunderstanding, commonly held, was that wood came from stuff sucked up from the ground whereas mostly the mass of wood comes from the air. But these misunderstandings, and many others like them, I am not going to document in the articles here at Wikipedia unless someone starts an article of common and comical misuderstandings

For these reasons I intend to replace the section with a simple reference such as See also: orbit. But I also intend to remove it because it is plainly off topic. Comment invited.

Paul Beardsell 10:32, 3 Oct 2004 (UTC)

Now this is very interesting. I've never heard that "space equals orbit" is a misconception at all. On the contrary - I know a space lawyer (Dr Gyula Gál, from Hungary, member of International Institute for Space Law), who's been with international collegues for many decades arguing that we should adopt a "functional" definition of space activities - that is, of considering an activity "space activity" if it is an orbital activity, or at least part of an orbit (if I get it right - someone with more knowledge pls correct). So eg. a balloon or a rocketplane flight would not be space flight, even if it goes to a hundred km (and so considered to be in the airspace of the given country). Sweden eg. doesn't define a suborbital research rocket as spacecraft even if it goes above 100km.

One problem with the 100km (or whatever) line comes from the fact that as long as the craft is under 100km, it will be in the airspace of a country. And in some countries (which are too small), it'll necessary go in another countries airspace before reaching 100km or orbit. So these guys claim that space activity begins with launch and ends with landing, and this whole process should be treated as being in space (applying the relevant international space treaties for search,rescue and disaster payments etc)

Another topic is about self-defence: for defending against ICBM etc, countries don't look at strict limits of air sovereignty. Eg. Hungary defines air sovereignty where air travel is physically possible, so about 35-40km, but would (if were able to...) defend herself at higher altitudes if necessary.

The UN Committee on the Peaceful Uses of Outer Space has been arguing over it for decades (since 2222/XXI on 1967), and they (contrary to the FAI) have not reached decision. Of course, it is much less of a significance for the FAI, it's only record-keeping; but for UN it's about law and sovereignty.

So I think this article should mention this problem. After all, the UN/COPUOS is at least as great a body as FAI or US. (Actually who cares about FAI? As someone pointed out, they wouldn't even treat Vostok-1 as spaceflight... who asked them anyway?)

Article in Hungarian:

There's probably much more (and in English) hidden at but it's too much (and legalese) for me to read through now.

Hoemaco (talk) 05:49, 7 October 2008 (UTC)

Uses of External links[edit]

Also see the article on the Kármán line under External links below, which has an excellent explanation on how this boundary was determined.

The explanation should be incorporated into the article, not mentioned in passing. --[[User:Eequor|η♀υωρ]] 01:48, 5 Oct 2004 (UTC)

Boundary to space / Karman line as title[edit]

(William M. Connolley 17:38, 28 Nov 2004 (UTC)) It seems very odd to me to use Karman line as the "main" title for this page rather than the far-more-obvious boudary to/of space.

Boundary to space is certianly more clear and specific, but is there such a thing? Duk 18:29, 28 Nov 2004 (UTC)
(William M. Connolley 19:44, 28 Nov 2004 (UTC)) If there isn't such a thing, then the article is in need of revision: The boundary to space or edge of space, according to definitions by the Fédération Aéronautique Internationale (FAI), lies at a height of 100 km (about 62 miles) above Earth's surface (ie. in technical terms 100 km above mean sea level).
Yes, good point. Further down in the article there is a note;FAI apparently doesn't itself use the precise words "boundary to space" or "edge of space". Duk 19:58, 28 Nov 2004 (UTC)
Some of the sections should be moved to outer space.
I think that "Karman line" is a more appropriate main title for this page. The article states "Strictly speaking, there is no such thing as an end to Earth's atmosphere: An atmosphere does not technically end at any given height, but becomes progressively thinner with altitude." The article is about the line which is used to determine at what point something is considered to be "in space", not about a location where the Earth's atmosphere suddenly ends and space begins. Since there is technically no "edge of space", and the aticle mentions this fact repeatedly, I don't think it makes sense to call the article "Boundary of Space". --Vsst 03:30, 20 March 2007 (UTC)
Agreed. This article is not about the (singular) boundary between the atmosphere and space. Instead, it is about the altitude at which conditions change such that astronautics rather than aeronautics is the relevant engineering discipline involved in flight. (It's unfortunate but understandable that the FAI also uses it as the altitude at which travelers are considered to have become astronauts.) Sdsds 04:51, 20 March 2007 (UTC)


it would be neat if the image were broken up and displayed on each of the pages for spheres, and each section of the image were clickable and went to the article on that sphere. but still looked the same as it is. probably possible with a table. like an "atmosphere taxobox". - Omegatron 01:08, Jan 8, 2005 (UTC)

It would also be better if the image showed the Karman line. User:Zntrip00:44, 15 August 2005 (UTC)

yeah, I agree. am I allowed to edit the image to include the karman line? (not sure about copyright issues) -- 10:34, 17 October 2006 (UTC)

Karman line equivalents[edit]

Has anyone ever calculated the equivalent of the Karman line for other planets, such as Mars, for example.

Apparently not, but it would be a great addition to this article to find a source that has done so! For that matter, it would be great to find a source the explains the calculation Kármán did to get approximately 100 km for Earth. (Musn't the calculation assume something about the maximum ability of a wing to create lift at a given air pressure, and something about the decrease in air pressure as altitude increases?) Given a recreation of the calculation for Earth, creating one for Mars might be within the capabilities of mere aerospace amatuers. (sdsds - talk) 06:28, 2 September 2007 (UTC)

The Kármán line in Venus is around 250 km high, and in Mars about 80 km [1].

AP magnetic index[edit]

Hi. The article uses the term "AP magnetic index", which is mysterious to this casual reader, and which Wikipedia doesn't have an entry for. Reading this page I'm thinking a better substitute is "fluctuations in the Earth's magnetic field". Does that seem right? William Pietri 06:21, 20 September 2006 (UTC)


In looking for references, I noticed that much (not all) of the article is reproduced directly from this one:

Again, the entire article is not copied, but many sentences are duplicates from the website. E_dog95' Hi ' 23:04, 29 April 2008 (UTC)

I believe it is the other way around, if there is a connection. Looking through the article history, there is no point at which the wording of this website was suddenly adopted. Indeed, the very first revision starts with “Strictly speaking of course, there is no such thing as an end to earth's atmosphere: The atmosphere doesn't technically end at any given height, but it gets progressively thinner the higher you go.” The article progressed organically from there. EdgeOfEpsilon (talk) 21:56, 19 May 2008 (UTC)

The article was started by User:Ropers (note the date of the first edit, 20 June 2004). It was initially named Edge of space, but then moved around quite a bit, first to boundary to space, then Karman line, then Kármán line. Now note the date the above website was created:

$ whois

Welcome to MYNIC Whois Server.
  For alternative search,
   whois -h xxxxx#option

  Type the command as below for display help: 
  whois -h #h



a [Domain Name]   
b [MYNIC Registration No.]  D1A076017
c [Record Created]          15-MAR-2007

The above website has definitely copied from Wikipedia, not the other way around. I am removing the copyvio template, but maybe someone wants to check if the other website is in GFDL compliance and contact them if applicable?. (talk) 21:29, 31 May 2008 (UTC)

Use of "edge of space"[edit]

The FAI apparently does not itself use the precise words "boundary to space" or "edge of space"

Some people (including the FAI in some of their publications) also use the expression "edge of space"

These 2 statements seem contradictory. Which is correct? AstroMark (talk) 22:16, 18 June 2008 (UTC)

Neither statement belongs in the article without a reference citing a reliable source. Wikipedia:Verifiability, which is policy, reads: "Editors should provide a reliable source for quotations and for any material that is challenged or is likely to be challenged, or the material may be removed." (sdsds - talk) 23:03, 18 June 2008 (UTC)

Need new article[edit]

This article, Kármán line is great. But as a recent IP edit notes this article isn't about the "Boundary of space"; this article is about one definition of the boundary of space. The IP editor removed the section of this article discussing e.the U.S. definition of "astronaut" and the altitude required for astronaut wings. Rightly so! This article is about the Kármán line, for which the U.S. definition isn't relevant. What wikipedia needs is a new Boundary of space article which doesn't redirect here, but which instead references the Kármán line article and then mentions other definitions as well. (sdsds - talk) 05:03, 20 July 2008 (UTC)

I changed the article before I noticed your comments here. I put the material back and renamed it. I just wanted to say that and that your new article idea sounds fine. E_dog95' Hi ' 20:04, 20 July 2008 (UTC)

A different boundary of space[edit]

Edge of Space Found

The proposed limit is 73 miles/118 kilometers. RandomCritic (talk) 02:23, 10 April 2009 (UTC)

About lifting limit[edit]

That is a troublesome definition. Isn't the aerodynamic lift dependent on technology? I mean, a glider has a better lift than, say, the space shuttle. Thus advances in technology will push away the limit of space, and before the Wright brothers, space started at 0km??? Tony (talk) 15:20, 10 April 2009 (UTC)

I think that flight utilizing aerodynamic lift has been around since the Carboniferous. RandomCritic (talk) 15:53, 11 April 2009 (UTC)

I do think the same, Bruguiea. What kind of vehicle did Kármán take when doing his calculations? If you take a plane and other with wings two times longer, but a same weight...--Andrestand (talk) 17:42, 2 June 2009 (UTC)
I have a friend who used to be an aeronautical engineer. I was discussing space (and Kerbal Space Program) with him and mentioned the Karman Line, which he hadn't heard of. I explained it in the same terms as this article - that it's the altitude where your airspeed must be so fast that it's orbital velocity. He immediately said "but your lift depends on your wing area as well. What size wing are we talking about?". So, what size wing ARE we talking about? If your wing area was big enough, could you not get above 100km without reaching orbital velocity? — Preceding unsigned comment added by (talk) 01:42, 21 July 2016 (UTC)

Andrew G. Haley[edit]

Shouldn't the fundamental role of Andrew G. Haley be mentioned in this article?[1][2] Regards, RJH (talk) 23:21, 23 October 2011 (UTC)

Proper noun pedantry[edit]

To be very pedantic, shouldn't it be "Kármán Line" as the full term is a single proper noun? (e.g. Eiffel Tower, Grand Canyon). (talk) 02:49, 15 January 2012 (UTC)Martyn


When was the Kármán line defined/adopted? That information should be in the article but currently isn't. (talk) 03:52, 30 April 2012 (UTC)

Orbital velocity vs. escape velocity[edit]

Multiple times, this article uses the term orbital velocity and links to the orbital velocity article. The problem is, that's not an article; it's a disambiguation page, and we're not supposed to link to those. And none of the three articles the disambiguation page points to match the way the term is used here. The closest match is orbital speed, but that's just the speed of an orbiting object. I think escape velocity is what was intended, but perhaps there's some nuance I'm missing. If escape velocity is in fact the right term, then why don't we use that term? Is orbital velocity a synonym for escape velocity in some regions or contexts? Please comment if you know more. —mjb (talk) 23:42, 28 October 2012 (UTC)

Orbital velocity in this article presumably refers to the speed necessary for a circular orbit of a given height, 100 km in this case. Escape velocity is the speed necessary to completely escape the Earth (keep moving away and never come back) starting from a given height. Escape velocity is always 1.414 (square root of two) times faster than the orbital velocity of a circular orbit at a given height. Brian Wowk (talk) 05:17, 1 May 2013 (UTC)

Is centrifugal force included in the Karman Line calculation ?[edit]

Neither the article, the source it points to, or other sources I can find, clearly state whether weight reduction due to centrifugal force is considered in the calculation of what speed a vehicle must travel at to generate sufficient aerodynamic lift to support itself. To illustrate the problem, it makes no sense to say "any vehicle at this altitude would have to travel faster than orbital velocity in order to derive sufficient aerodynamic lift from the atmosphere to support itself" because a vehicle at orbital velocity needs no aerodynamic life to support itself against falling back to Earth. The centrifugal force associated with orbital velocity reduces the vehicle's effective weight to zero, which is the meaning of being in orbit. So what's the deal? Perhaps the Karman Line is the altitude at which orbital velocity is necessary to generate aerodynamic lift equal to the vehicle's own weight at rest? In other words, it's the altitude at which orbital speed is necessary to keep flying in a straight line rather the follow the curve of the Earth? That seems to make the most sense since 100 km is already sensible atmosphere to reentering spacecraft, and a back-of-the-envelope calculation shows that vehicles hitting atmosphere at that altitude at orbital velocity would experience on the order of one gee of force. I'll edit the article to clarify this point. An interesting implication is that contrary to Karman Line descriptions, you can in fact use aerodynamic lift to remain aloft at altitudes above the Karman line while traveling at speeds somewhat less then orbital (if you can take the heat). This is how reentering spacecraft hitting Karman line altitudes at orbital velocity at shallow angles can actually bounce off the atmosphere back into space. They still "fall" in the sense of following a trajectory curved toward the Earth due to insufficient lift, but Earth's surface curves away faster. Brian Wowk (talk) 07:04, 1 May 2013 (UTC)

"International Law" definition[edit]

I've done some pretty extensive research on this, and no where can I find any source stating that in International Law space is defined as it says in this article. In fact, based on this United Nations memo I'd say it is pretty definitive that the UN has NOT agreed on any such definition: — Preceding unsigned comment added by Spaceguy2015 (talkcontribs) 21:03, 2 May 2015 (UTC)

Clear it up[edit]

Can someone clear this article up. The americans tried to invent a fake definition of what Space was so they could hand out medals and pretend some dead pilots were astronauts. It should be mentioned as an aside but some derper seems to be trying to pretend it's a legitimate definition. There doesn't seem to be any mention of other fictional beliefs like the vault of heaven or Apollo's chariot. — Preceding unsigned comment added by (talk) 02:07, 27 August 2015 (UTC)

External links modified[edit]

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  1. ^ Isidoro Martinez