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Recently the Billionaire Space Race culminated with both Jeff Bezos and Richard Branson, doing what I can tell without any dispute, "going up" and "coming down". The claim that either of them actually reached space however is hotly debated, with astrophysicist Neil deGrasse Tyson telling (paraphrased from this article)

First of all, it was suborbital...If you don't go fast enough to reach orbit you will fall and return to Earth...It's okay if you want to call it 'space,' just because average humans haven't gotten there before and it's a first for you. That's why it takes eight minutes to get into orbit and three days to reach the moon...So I don't see it as 'oh, let's go into space'. No. What you are going to have is a nice view of the Earth

According to CNN, Neil deGrasse Tyson says that neither Richard Branson nor Jeff Bezos has actually been put into orbit.

Of course, we got Elon Musk chiming in and trolling Bezos (I can't find the original one I saw so I am not sure if this is the real one).

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So where exactly does the Space start according to Governments and governmental agencies? Specifically speaking is there any legal definition of Outer Space in law.

[Edit I am citing NdT and Elon to only show there is a dispute/debate. Their opinion need not be legally considered]

My research

At the Legal Sub-committee meeting of 2018 UN COPUOS, United Nations the Committee for the Peaceful Use of Outer Space, some member states considered that a definition of where air space ends and outer space begins, was important because of space tourism and other activities extending to space. However, others including the US under Bush Administration pointed out that we have done quite well without such definitions and this has caused no problems so far.

Historically, it’s been difficult to pin that point at a particular altitude. In the 1900s, Hungarian physicist Theodore von Kármán determined the boundary to be around 50 miles up, or roughly 80 kilometers above sea level. Today, though, the Kármán line is set at what NOAA calls “an imaginary boundary” that’s 62 miles up, or roughly a hundred kilometers above sea level.

The Federation Aeronautique Internationale (FAI), which keeps track of standards and records in astronautics and aeronautics, also defines space as beginning a hundred kilometers up. It is, after all, a nice round number.

But the Federal Aviation Administration, the U.S. Air Force, NOAA, and NASA generally use 50 miles (80 kilometers) as the boundary, with the Air Force granting astronaut wings to flyers who go higher than this mark. At the same time, NASA Mission Control places the line at 76 miles (122 kilometers), because that is “the point at which atmospheric drag becomes noticeable,” Bhavya Lal and Emily Nightingale of the Science and Technology Policy Institute write in a 2014 review article.

link

Adil Mohammed
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    What I don't understand is why NdGT makes such a big deal about actually orbiting. The definition of space is one dimensional (meters above sea level)(the actual value being the subject of debate) and not about orbiting or not. – Sandy Aug 01 '21 at 22:16
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    Technically, if you think about it, whenever somebody jumps up into the air they moving through outer space because all the space above the surface of the Earth is part of the outer space that surrounds our planet. – user57467 Aug 02 '21 at 00:54
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    @Sandy think about it the other way, if "requires actual orbital ability" was a requirement, a lot of early US astronauts would have to hand their wings back... –  Aug 02 '21 at 03:03
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    @user57467 But in this context "reaching space" is having reached X meters above sea level, not just being in the space above the surface of the Earth. The definition of being in "space" is not that ambiguous. – Sandy Aug 02 '21 at 07:59
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    @user57467 Technically, we live on a rock that's in space, so we don't have to do anything to get there. We're already there. – Don Branson Aug 02 '21 at 13:43
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    @DonBranson But we're not in outer space. – Stef Aug 02 '21 at 14:24
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    @Sandy: As an educator, Neil deGrasse Tyson is concerned with correcting people's misconceptions about space, and people have a lot of misconceptions about getting into orbit — including the idea that the "hard part" of orbital space flight is getting high enough off the ground, and then you can effectively just floating around. See also Randall Munroe's article correcting the same misconception. – Michael Seifert Aug 02 '21 at 14:29
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    "Orbit" and "orbiting" are about your velocity, whereas "space" is variously defined by altitude/elevation. They are two different things with no direct relationship to each other. Neither Bezos nor Branson came close to being orbital. – RBarryYoung Aug 02 '21 at 15:43
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    @Moo: The only suborbital Mercury flights were Alan Shepard and Gus Grissom, who later did orbital flights (Apollo 14 and Gemini 3, respectively). I suppose you could count Joseph A. Walker (an X-15 pilot who crossed the Kármán line on two flights, but never orbited), but one is not "a lot". – dan04 Aug 02 '21 at 16:27
  • Given enough fuel (a non-realistic amount, I must say), one can go to the moon in a suborbital trajectory. One can realistically go past the international space station and not achieve orbit. That because orbit is about tangential velocity, not about altitude. – lvella Aug 02 '21 at 17:01
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    @dan04 there are 8 X-15 pilots who have been awarded astronaut wings - 5 USAF pilots who received them in the 1960s, and 3 NASA pilots who were retroactively awarded them in 2005. –  Aug 02 '21 at 19:30
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    There is no uniform definition. Different definitions apply for different purposes. – ohwilleke Aug 02 '21 at 21:19
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    Scott Manley covered the history and arguments on how they arrived at it (from 10 min 28 secs) - "50 miles ... rounded to 80 km.". "...SpaceX ... yeah, but you didn't go orbital" – Peter Mortensen Aug 03 '21 at 09:06
  • @MichaelSeifert As an educator, he shouldn't bring up something entirely unrelated to the discussion - that just adds more confusion. One can go up way higher than most satellites which are undoubtedly 'in space', and still not achieve an orbit... but they'd still be in space. Voyager 2 is not in orbit, is it not in space? – Rob Aug 03 '21 at 10:06
  • @RBarryYoung Yes but neither claim to have been in orbit, only to have been in space as defined as X meters above sea level. – Sandy Aug 03 '21 at 11:46
  • @Sandy My comment was directed to the conversation on this page generally, which seemed to be blurring the distinction and misunderstanding the difference. – RBarryYoung Aug 03 '21 at 13:35
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    @lvella: More to the point, establishing a practical orbit requires raising the perigee and not just the apogee. Almost any object moving in a vacuum will be on an orbital path about the center of the Earth, but their usefulness as orbits would be impeded by the presence of an obstacle. – supercat Aug 03 '21 at 14:54

2 Answers2

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Where does outer space legally start?

International law does not define the edge of space, or the limit of national airspace according to footnotes 2 and 3 of the Kármán line's Wikipedia entry.

Footnote 15, referencing the book International Law: A Dictionary by Boleslaw Adam Boczek, offers this:

The issue whether it is possible or useful to establish a legal boundary between airspace and outer space has been debated in the doctrine for quite a long time. … no agreement exists on a fixed airspace – outer space boundary …

  • Ugh i wished i had read that last line earlier... so how do countries say "hey you have entered my airspace and you are no longer in outer space" or is the issue of airspace delimitation handled case-by-case? – Adil Mohammed Aug 02 '21 at 15:23
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    @AdilMohammed: Practically speaking, if it has wings, it's an airplane and the airspace question is relevant. The Space Shuttle would be a difficult case with that definition, had it ever landed outside the USA. But it obviously was in space when over other countries. – MSalters Aug 02 '21 at 16:13
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    @AdilMohammed: I've heard it as a matter of being in orbit or not. Note that the ISS is in near earth space not outer space. – Joshua Aug 02 '21 at 17:51
  • @Joshua yes that's one of the ways it is being/can be judged. like I said I wished I read that last line. I was researching for quite a while. Other countries judge on the destination/intent. But I don't remember coming to a conclusion that there was an international consensus (and hence the slash you saw in the first line) – Adil Mohammed Aug 02 '21 at 18:47
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    @MSalters I have heard that 'technically' the country's airspace sovereignty extends to many altitudes, but practically it's only just as much as high as their anti-satellite guns can shoot. Not sure about the "wings" part, I read that space shuttles too have special wings. Need to look more into it – Adil Mohammed Aug 02 '21 at 18:49
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    @Adil Mohammed There is no international agreement on the vertical extent of sovereign airspace (although this is an uncited claim) –  Aug 03 '21 at 13:35
  • @RockApe "But the term espace aerien is most commonly construed to mean the space extending ad Infinitum. ICAO itself seems to support this interpretation"... link. espace aerien sounds like space air ≈ air space – Adil Mohammed Aug 03 '21 at 13:53
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100km

According to the Fédération Aéronautique Internationale who are generally considered the record-keeping body on such matters, the Kármán line is where space begins and is rounded off to 100km above the Earth’s surface.

Of course, this is a Sorites paradox definition because there is no line where Earth’s atmosphere ends. The ground is definitely inside it (even at Mt Everest) and the Moon is definitely outside it. So, somewhere between those two.

In law, these sorts of category laws sued can be resolved in two ways: the legislation can define a hard border, such as a set age for voting or drinking, or it can leave it to be decided on a case-by-case basis, such as reasonableness.

The various “outer space” treaties do not actually define outer space. However, most regulatory bodies including the UN accept the FAI definition: if it flies below that, it’s an aircraft, above that, it’s a spacecraft.

Of course, it’s much easier to get things into space than to get them in Earth orbit. Space is just a matter of going up. Orbit requires going around and is much harder, breaking the axiom of “what goes up, must come down.”

Of course, if you want to get really pedantic, you’re not in space until you reach the heliopause, which both Voyager 1 & 2 have achieved or, if you’re really serious, intergalactic space.

As for what constitutes “achievement” both my kids have ribbons for rugby league although neither played beyond the age of 14. I could get them to jump tomorrow and give them astronaut’s wings.

Dale M
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    "most regulatory bodies including the UN accept the FAI definition: if it flies below that, it’s an aircraft, above that, it’s a spacecraft." Could you cite/name the bodies. the main reason I kept Karman line in the research part and not in the main part, was because I thought it was probably only a scientific definition not a legal one. Also +1 for last line – Adil Mohammed Aug 01 '21 at 17:16
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    This answer drifts around to a lot of stuff without clearly addressing the legal question. –  Aug 02 '21 at 00:10
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    @BenCrowell because theres no true legal answer? Space isn't something that is legally defined in the form of legislation or treaties, its something that several independent bodies (FAI, US government, NASA etc) define for their own requirements and other people accept. –  Aug 02 '21 at 03:04
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    Is it only US agencies that give astronaut wings? Does the EU have anything similar? – Sandy Aug 02 '21 at 08:54
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    "the Kármán line is where space begins and is rounded off to 100km above the Earth’s surface" – If by "rounding off" you mean "von Kármán computed the value to be 83.82 km / 52.08 mi, the US decided to round this off to 50 miles, the FAI decided to round it up to 100 km". Personally, I wouldn't call 83.82->100 "rounding off". – Jörg W Mittag Aug 02 '21 at 09:44
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    Re, "the Kármán line...is rounded off..." It's defined to be exactly 100km above mean sea level. It's named for Theodore von Kármán, because he was the first to propose a definition of "outer space," but Kármán's line wasn't a definite altitude: It was the "line" between flight and orbit. Back in the day, they weren't trying to go to space on ground-launched rockets. The dream was to fly into orbit in a rocket-powered airplane. Kármán proposed a formula to decide whether a "space plane" was truly orbiting, or still just "flying." The exact height would depend on characteristics of the plane. – Solomon Slow Aug 02 '21 at 11:43
  • @BenCrowell : but the title of the question seems to stem from a misunderstanding of the quote, and this answer clears that popular misunderstanding quite well. Tyson and Musk were not saying Bezos and Branson didn't reach space, they stated that they didn't achieve orbit, which would have been a significantly bigger and harder achievement than just merely reaching space and falling back down. It basically shows that calling it a spaceflight is like calling this contraption an aircraft: sure, it flew for a bit, but we wouldn't really call it air travel. – vsz Aug 02 '21 at 12:23
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    @JörgWMittag I’m an engineer and that’s exactly what rounding off means. – Dale M Aug 02 '21 at 12:24
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    "(...) the Moon is definitely outside it." Why definitely? – WoJ Aug 02 '21 at 14:01
  • @WoJ: Because everyone agrees that the Moon is unambiguously in space. And legally, I'm pretty sure there are also treaties recognizing that the moon is not in the legal jurisdiction of terrestrial nations, and definitely not based on which one happens to be under the moon at the moment. I think the answer would work as well with the ISS or a geostationary satellite as the reference, but the moon is a natural satellite, and is even more unquestionable than any artificial satellite. – Peter Cordes Aug 03 '21 at 12:29
  • @DaleM It is indeed rounding, though extremely low precision rounding. Something like 84 or 85 km would have been a much more reasonable rounding. It's a good thing the meter isn't twice as long as it is, or else their "round to the nearest 100 km" strategy would have estimated the Karman Line at the surface. :) – reirab Aug 03 '21 at 16:06
  • On the positive side, though, if the meter had indeed been twice as long and they still rounded to the nearest 100 km, then having your kids jump and giving them astronaut's wings would have been recognized by FAI (as least as long as they were above sea level at the time.) - haha – reirab Aug 03 '21 at 16:14
  • @JörgWMittag Interestingly while researching turns out Karman did say it was 82.3 (I don't remember exactly) But the FAI just rounded it off to 100 and that continued till someone recently pointed it out. So yeah FAI revised it recently and now it's 82.3 again. Link – Adil Mohammed Aug 05 '21 at 11:51