According to International Law, to what altitude does the jurisdiction of a state extend? Is there a definite limit mandated either through treaties or court judgements?

After reaching that limit, do we find ourselves in the outer space regulated by space law? Is there a layer of international space, regulated by other treaties?

This is a very practical question: To what altitude may launched spacecraft or satellite ascend/descend without violating the air territory of a sovereign state?

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    $\begingroup$ A Google search will very quickly show that the official boundary of space is at 100 km. I think a better question would be at what height does it become international territory, before it reaches the boundary of space. $\endgroup$
    – Gwen
    Jul 17, 2013 at 5:49
  • $\begingroup$ You are right, I have modified the question to ask also about that aspect. $\endgroup$
    – user43
    Jul 17, 2013 at 5:51
  • $\begingroup$ this have some relevant information. $\endgroup$
    – nos
    Jul 26, 2013 at 19:51

2 Answers 2


The general rule of thumb on this type of issue is that if it is in orbit, then you don't have to worry about traveling through other countries, and if it is not yet in orbit, you should ask permission from whatever country you are flying through. For this reason, and safety reasons in general, most spacecraft launch from the coast. Thus, a sub-orbital flight is still maintained by the country below it, but an orbital flight would not be.

Of course, like ships, Orbiting vehicles are subject to their registered nation, but that's another issue entirely.

A few other things of some interest:

  1. Geostationary satellites are theoretically governed by the country around which they orbit, to an extent. However, the countries that have tried to maintain this claim can't enforce it, so it hasn't been a significant issue. Equatorial countries try to make such claims, but they really aren't enforceable, so...
  2. Once you go beyond the surface of the Moon, then international law about what frequency you can use no longer applies. However, if you plan on talking back to Earth, you should coordinate. This could be used for a special purpose radar orbiting Mars, for instance.
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    $\begingroup$ Sorry to jump on an old post, but the details here aren't accurate. Your general point about not worrying about overflight in space is right on, but the GEO, frequency, and past-the-orbit-of-the-moon stuff doesn't have a basis in any of the existing treaties or in customary law. I've tried to set things out in my own answer. $\endgroup$ May 23, 2018 at 20:57

There is no internationally agreed-upon definition of "outer space", or delimitation between outer space and airspace. The 1967 Outer Space Treaty does not contain a definition of the term "outer space". This was intentional, because states have significantly greater freedom of action in outer space than they do in airspace. Specifically, the Outer Space Treaty provides for freedom of use and access in outer space, while airspace is sovereign territory. Bottom line is that you can overfly another country if you do it in outer space, but not if you do it in airspace. For that reason, some countries have intentionally prevented the formation of an internationally agreed definition of outer space in order to maintain freedom of action in very low but still basically orbiting activities.

In practice, however, these edge cases aren't at all common, and the lack of a delimitation between outer space and airspace hasn't caused any practical problems. That's another reason why some countries don't see a need to answer the question.

There are countries that have adopted a definition for their own legal purposes, however. These definitions generally follow either an altitude-based approach (generally tracking the Karman line) or a functionalist approach, under which outer space is considered the altitude at which orbital flight is possible without utilization of atmospheric lift, or something to that effect. But these definitions all vary and there is no international standard.

With regard to objects in GEO, the states (here I mean countries) located below them do NOT have some kind of legal claim or jurisdiction. Some countries tried to argue this a while back, and those arguments have all been soundly rejected. Communications satellites in GEO are subject to frequency and orbital allocation rules set out by the International Telecommunications Union, as well as being regulated by their launching state, unless operations have transferred to an entity located in another state. Otherwise, the general rules about freedom of use and access set out in the Outer Space Treaty apply.

So, to simplify: if you go straight up and straight back down (more or less), no one is going to care other than the country you launch from. If you go above the karman line, some countries will think you went into outer space, but hey, you have freedom of use and access there anyway. If you want to overfly a country, you need to either be unambiguously in outer space, like high enough to orbit a bit without propulsion or lift effects, or at an altitude that the country in question itself considers to be outer space.

  • $\begingroup$ +1 though what about the sub-orbital phase, i.e. regardless of whether a sounding rocket or the first/second stage of an orbital vehicle. Do ambassadors get sent to exchange words if there is an overflight of a sub-orbital vehicle? $\endgroup$
    – Puffin
    Mar 25, 2021 at 11:01
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    $\begingroup$ Good question. In every instance I know of, the launching state provides prior notification to the overflight state. This is a courtesy, and also allows the overflight state to issue a NOTAM in case of a mishap that could affect aviation. But the most common interpretation of the "freedom of access" to space provisions of the Outer Space Treaty is that you don't legally HAVE to get consent to overfly so long as you are on the way to space. Not sure overflight has ever come up for a non-orbital launch. $\endgroup$ Mar 26, 2021 at 15:30
  • $\begingroup$ For the country being overflown, from a practical perspective "surely" it would make a difference if "on the way to space" meant "only overflies on a successful mission after last stage burnout" instead of, "overflies before stage burnout and / or in fault scenarios" $\endgroup$
    – Puffin
    Mar 26, 2021 at 23:47
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    $\begingroup$ Interesting. The generally accepted position for that would likely be that it's not unlawful to overfly in that way but that the launching state is "strictly liable" for any damage caused on the ground (or to aircraft). So they have to pay compensation whether or not they did anything "wrong". SpaceX has dropped some stages into Bahamian waters as well, which legally is the same as land territory, but haven't damaged anything. It's quite bad practice to do this if you aren't providing notice, don't know if China does. $\endgroup$ Mar 27, 2021 at 19:46
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    $\begingroup$ PS: No reason to doubt the authenticity. Sounds like something that would happen, assuming the trajectory makes sense. $\endgroup$ Mar 27, 2021 at 19:48

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