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A geostationary orbit is a circular orbit in Earth's equatorial plane whose rotation period matches that of the Earth.

The "geo" in "geostationary" means Earth, so is there another term to designate similar orbits around other planets?

usernumber
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4 Answers4

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I'll go with Emily Lakdawalla who in her blog post about stationkeeping in Mars orbit wrote (emphasis mine),

What is a geostationary orbit like at Mars? I have to pause here for a brief discussion of semantics. The authors of this paper discuss "areostationary" for Mars orbits as opposed to "geostationary" for Earth, and Wikipedia uses the same convention, but I'm not a big fan of this sort of nomenclatural hair-splitting. You'd have to talk about "hermestationary" for Mercury, "cronostationary" for Saturn, "selenostationary" for the Moon, and so on. It gets tiresome. And while a very few people use "areology" to name the study of rocks on Mars and "selenology" to talk about rocks on the Moon, nearly everybody calls it all "geology" and a person who studies all that stuff a "planetary geologist." So I'm going to stick with calling it a "Martian geostationary orbit."

In addition to Martian geology and Martian and geography, people also write and talk about Martian terrain and Mars as a terrestrial planet. All of these terms, along with Martian geostationary orbit are incorrect from a pedantically correct point of view. The solution is easy: It's the overly erudite attempts at being pedantically correct that are incorrect.

David Hammen
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    Big time. Language changes. – T.J. Crowder Nov 30 '19 at 09:11
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    I'd simply drop the geo- and talk about stationary or better yet surface-stationary orbits. Its general enough for any body, precise enough to not ne misunderstood and avoids the pitfall of having to argue with pedantics about "geo-". – Polygnome Nov 30 '19 at 21:10
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    I'm not sure even an etymology pedant would object to calling Mars a "terrestrial planet". That's just using the "Earth-like" definition of "terrestrial", rather than the "on Earth" definition. – David Richerby Dec 01 '19 at 10:53
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    @Polygnome : why? People know and use geo- all the time, so why change it to confuse them? Mars isn't a person who can be offended by that (a reason many advocates of political correctness use to justify changes which make communication more difficult but are justifying them because it makes some people less likely to be offended) – vsz Dec 02 '19 at 10:07
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    @vsz Because it doesn't add clarity. Surface-stationary is generic & specific enough, while it avoids the whole discussion of whether geo- is appropriate for non-Earth bodies. Personally, I have nothing against "geostationary", but I find it pointless to have the discussion. Surface-stationary is a term that says what one wants to say, can be easily understood by both the crowd that is for geo- and the crowd that is against geo-, so why not use it? – Polygnome Dec 02 '19 at 11:18
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    @Polygnome - "...and avoids the pitfall of having to argue with pedantics about "geo-"" "pedantic" is an adjective. The noun for a pedantic person is "pedant." (See what I did there? Ducks and runs... ;-) ) – T.J. Crowder Dec 02 '19 at 17:15
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    @Polygnome Of course it adds clarity. Especially among laypeople to whom you then have to explain the difference between a geostationary and surface-stationary orbit. – user253751 Dec 02 '19 at 18:07
  • @user253751. Don't forget about geosynchronous vs geostationary (vs surface-synchronous vs surface-stationary, of course) – Mad Physicist Dec 02 '19 at 20:58
  • @Polygnome : the problem with surface-stationary is that it seems to be a word you just made up. I searched for it without any success. If you want to introduce new terms into the English language, this site is not made for that purpose. – vsz Dec 04 '19 at 06:38
  • @vsz its not a really common term (yet), because it isn#t needed all that often (which is why I said in my answer we will need to see which term catches on long-term), but it definitely isn't coined by me and pre-dates my using it here (e.g. in this paper from 2008 or in this reddit thread where it is easily understood without explanation by all concerned parties (I am not the author of that comment). – Polygnome Dec 04 '19 at 10:45
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Geostationary orbits are synchronous orbits, which are also circular and equatorial.

You could describe orbits around other planets in the same way, as circular, equatorial & synchronous orbits.

For Mars, the terms areostationary and areosynchronous are (sometimes) used. This follows the convention of how apsides are named, so it is likely that the convention used for apsides would be re-used for those orbits.

Note that this is all descriptive. We will know what terms catch on in the scientific and aeronautic community once there is the regular need to talk about such orbits and to distinguish them.

Some alternatives one might consider:

  • stationary orbit
  • surface-stationary orbit
  • fixed orbit

See https://en.wikipedia.org/wiki/Stationary_orbit

Polygnome
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Perhaps "Clarke orbit"?

The definitions always talk about Earth but at least it's not in the term.

https://en.m.wiktionary.org/wiki/Clarke_orbit

Organic Marble
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Consider the middling-future, when humans have put probes around other stars and other planets. We have run out of old Gods to mash into names like areostationary.

In this case, "geostationary" or "stationary" or one of the other generic naming conventions appearing in other Answers is appropriate.

Christopher Hostage
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