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In 1981 the USSR requested and was allocated seven satellite slots in 24-hr orbit for Earth observations, calling the system Prognoz

  • Whom was the request made to?
  • Who allocates/allocated satellite slots in Earth orbit?
  • Is there an international body to assign/refuse orbit parameters for a space-craft?
  • $\begingroup$ This is probably for US-KMO (УС-КМО); the Prognoz series had 10 satellites in highly elliptic orbit (eccentricity approx = 100) $\endgroup$
    – MSalters
    Nov 16, 2014 at 18:37
  • $\begingroup$ @MSalters This page lists inclinations of ~65° for the Prognoz SO-M sats. This fits pretty well with a tundra orbit which I believe is geosynchronous (24 hour). Prognoz 9 launched 1 July 1983. $\endgroup$ Dec 29, 2018 at 11:21
  • $\begingroup$ Update (all of two seconds later): Regarding US-KMO: "These satellites have been mistakenly described as Prognoz (unrelated to the earlier Prognoz SO-M programme)[8] as the positions they occupy are reserved with the ITU under the codename Prognoz." The actual US-KMO satellites had names like "Kosmos nnnn". $\endgroup$ Dec 29, 2018 at 11:22

3 Answers 3


Geostationary slots are a rare resource and are assigned to countries by the ITU (International Telecommunications Union) since they are mainly used for communications and broadcasting, and need deconfliction both in frequency allocation (to reduce interference - the main raison d'être of ITU-R as a division of the ITU) and in collision avoidance (tighter orbital boxes are costly in terms of lifetime xenon expenditure).

Almost everything else in orbit selection is based on the operator's discretion, provided the downlink and uplink frequencies do not conflict with other satellite, fixed and mobile services.

Orbits are checked through national space control centers, though, to avoid crossing paths with other satellites and space debris.

For more information on Geostationary services, please have a look at http://www.itu.int/ITU-R/space/snl/

EDIT: On sanctions and reprisals: violating an international treaty is bad since the culprits will find themselves shunned. States do have the ability and legal authority to jam or disrupt non-authorized transmitters that broadcast into their territories, so it shouldn't be surprising to the perpetrator to find his downlinks or uplinks jammed. It should be noted that GSO is far away from the Earth, and the link budgets are quite slim, so any modest interference will degrade the link beyond usefulness.

TL;DR - A non-state actor (a corporation) will be held liable by its national telecommunications (and space) authorities, while a non-compliant state will be unable to effectively use the slot in GEO due to easy counter-measures.

The usual disclaimer: I am not a space lawyer...

  • $\begingroup$ @Everyone - added into the answer. $\endgroup$ Nov 15, 2014 at 12:21
  • 1
    $\begingroup$ Note that the few nations capable of putting something in GEO also have nuclear, jamming, and anti-satellite capabilities. Plus if you can launch something into prograde GEO you can also launch something into retrograde GEO thus crippling global communications, permanently, in a day. So the whole process really depends on everyone involved being nice to each other. $\endgroup$
    – paul
    Nov 15, 2014 at 13:53

To add to Deer Hunter's response:

The ITU manages the radio spectrum that satellites use, not their physical location.

There are many examples of satellites being owned by different organisations whose ITU permitted orbital slots are exactly co-incident but for use with different frequency bands. It is then up to the owners of the satellites to avoid physical encounters.

There is a further detail which is that a satellite does not actually need ITU permission to use certain spectrum in a given orbital slot, and this is recognised by the ITU, if it does so on a "non-interference basis", i.e. taking their own care not to cause radio friequency interference to neighbours who might already have registered frequency rights.

There has been an interesting related case in the news very recently, see http://spacenews.com/russian-satellite-maneuvers-silence-worry-intelsat/ , in this case Intelsat had become concerned about the presence of a Russian satellite physically close to their own satellites. The article describes their concerns about the difficulties in establishing contact with the Russian satellite control authority but nowhere is there any mention of ITU permissions and, I suspect, this is because there is not necessarily any breaking of those particular conventions.


It seems this is at least partly handled at the country level, as Swarm, a US based company was recently fined by the US Federal Communications Commission for unauthorized orbits that apparently risked satellite collisions.

  • $\begingroup$ Hi Pedro. That's pretty interesting but I don't think this fully answers the question that was asked. Could you perhaps expand a bit on the US FCC's role in authorizing launches and how the FCC fits into the global scheme of things? As an aside, I'm pretty sure the slots mentioned are tundra orbits, not LEO ones as with Swarm (though that doesn't affect your answer). Thanks for your contribution! $\endgroup$ Dec 29, 2018 at 10:49
  • $\begingroup$ Someone edited out, but that is just my two cents on the matter. I'm not sure how to clarify the original question. I see no mention of the tundra thing on the original question btw, he just says orbits. So there we go, the FCC was clearly not happy about those. Contrary to other examples, this is an internal resolution entirely confined to the US justice system. $\endgroup$ Dec 29, 2018 at 10:58
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    $\begingroup$ Just made an edit myself; I think it answers the question a bit better now. I encourage you to add to your answer if you come across any additional information. $\endgroup$ Dec 29, 2018 at 11:04
  • $\begingroup$ The question was asking about who authorizes orbits at the international level. I mentioned tundra orbits since the USSR satellites mentioned in the question used them. Tundra orbits are a form of geosynchronous orbits and thus might be more tightly regulated than low earth orbits. I do like your answer though. One thing that's interesting about Swarm is that they launched on an Indian rocket so there's an international component as well. $\endgroup$ Dec 29, 2018 at 11:13
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    $\begingroup$ Yes indeed the geosynchronous orbits are more limited than all others combined (both in physical space and in electromagnetic spectrum space). But that maybe for now, with so many companies working on so many satellites in low orbits, not necessarily a regulation but they for sure need to talk to each other to avoid collisions. $\endgroup$ Dec 29, 2018 at 11:24

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