3 ms·

It's interesting that the "E" in GEO, LEO, MEO, HEO is short for three different things: https://www.esa.int/Enabling_Support/Space_Transportation/Types_of_orbi

It's interesting that the "E" in GEO, LEO, MEO, HEO is short for three different things: https://www.esa.int/Enabling_Support/Space_Transportation/Types_of_orbits https://www.esa.int/Enabling_Support/Space_Transportation/Ty...

foota 1y ago
It is the most common letter, but I agree that is funny.
perihelions 1y ago
It looks like (if I've parsed right) every one of them stands for "Earth", except that HEO alone can also be overloaded three ways (high-earth, highly-elliptical, and highly-eccentric). This is unimportant, but: a site:nasa.gov search shows all three "HEO" acronyms in common use, there; and even Wikipedia abbreviates it inconsistently across entries[0-2]. https://en.wikipedia.org/wiki/Medium_Earth_orbit https://en.wikipedia.org/wiki/Medium_Earth_orbit ("A medium Earth orbit (MEO) is an Earth-centered orbit with an altitude above a low Earth orbit (LEO) and below a high Earth orbit (HEO)") https://en.wikipedia.org/wiki/Highly_elliptical_orbit https://en.wikipedia.org/wiki/Highly_elliptical_orbit ("A highly elliptical orbit (HEO) is") https://en.wikipedia.org/wiki/High_Earth_orbit https://en.wikipedia.org/wiki/High_Earth_orbit ("In this article, the non-standard abbreviation of HEO is used for high Earth orbit[2]") [edit]: I overlooked the abbreviation of "geostationary equatorial orbit" for GEO, which brings it up to four different "E's"!
- N19PEDL2 1y ago
  > geostationary equatorial orbit I thought GEO stood for Geostationary Earth Orbit, since a geostationary orbit must be equatorial anyway. But actually "Earth" would also be redundant, since "Geo-" already stands for Earth.
  - perihelions 1y ago
    I understand it's both, but "equatorial" is more precise to distinguish it from GSO, a non-equatorial [g]eo[s]ynchronous [o]rbit. Otherwise, they would both be "GEO".
- seanhunter 1y ago
  The phrase "highly elliptical" is one where I know exactly what they mean but the more I think about it the more wrong it seems. It should be "Highly eccentric orbit". All shapes which satisfy {(x,y)| x^2/a^2 + y^2/b^2 = 1} for fixed values of a,b in R are elliptical. Something is either elliptical or not - it's not a matter of degree. A circle is just as elliptical as a more eccentric ellipse in the same way that a square is just as rectangular as a more elongated rectangle.
throw578547 1y ago
LEO is Low Earth Orbit MEO is Medium Earth Orbit The E is short for the same thing in this case. GEO for Geostationary and HEO for High-Eccentricity are interesting, though.
- seanhunter 1y ago
  MEO is Middle Earth Orbit. We have to keep an eye on what Gandalf is up to.
  - mcv 1y ago
    That orbit has only really been possible since the sinking of Numenor. Better make use of it now that we can.
  - tapland 1y ago
    SubEarthOrbit for the dwarves
    - seanhunter 1y ago
      …but they orbit too deep, and too greedily.

foota 1y ago

It is the most common letter, but I agree that is funny.

perihelions 1y ago

It looks like (if I've parsed right) every one of them stands for "Earth", except that HEO alone can also be overloaded three ways (high-earth, highly-elliptical, and highly-eccentric). This is unimportant, but: a site:nasa.gov search shows all three "HEO" acronyms in common use, there; and even Wikipedia abbreviates it inconsistently across entries[0-2]. https://en.wikipedia.org/wiki/Medium_Earth_orbit https://en.wikipedia.org/wiki/Medium_Earth_orbit ("A medium Earth orbit (MEO) is an Earth-centered orbit with an altitude above a low Earth orbit (LEO) and below a high Earth orbit (HEO)") https://en.wikipedia.org/wiki/Highly_elliptical_orbit https://en.wikipedia.org/wiki/Highly_elliptical_orbit ("A highly elliptical orbit (HEO) is") https://en.wikipedia.org/wiki/High_Earth_orbit https://en.wikipedia.org/wiki/High_Earth_orbit ("In this article, the non-standard abbreviation of HEO is used for high Earth orbit[2]") [edit]: I overlooked the abbreviation of "geostationary equatorial orbit" for GEO, which brings it up to four different "E's"!

N19PEDL2 1y ago
> geostationary equatorial orbit I thought GEO stood for Geostationary Earth Orbit, since a geostationary orbit must be equatorial anyway. But actually "Earth" would also be redundant, since "Geo-" already stands for Earth.
- perihelions 1y ago
  I understand it's both, but "equatorial" is more precise to distinguish it from GSO, a non-equatorial [g]eo[s]ynchronous [o]rbit. Otherwise, they would both be "GEO".
seanhunter 1y ago
The phrase "highly elliptical" is one where I know exactly what they mean but the more I think about it the more wrong it seems. It should be "Highly eccentric orbit". All shapes which satisfy {(x,y)| x^2/a^2 + y^2/b^2 = 1} for fixed values of a,b in R are elliptical. Something is either elliptical or not - it's not a matter of degree. A circle is just as elliptical as a more eccentric ellipse in the same way that a square is just as rectangular as a more elongated rectangle.

throw578547 1y ago

LEO is Low Earth Orbit MEO is Medium Earth Orbit The E is short for the same thing in this case. GEO for Geostationary and HEO for High-Eccentricity are interesting, though.

seanhunter 1y ago
MEO is Middle Earth Orbit. We have to keep an eye on what Gandalf is up to.
- mcv 1y ago
  That orbit has only really been possible since the sinking of Numenor. Better make use of it now that we can.
- tapland 1y ago
  SubEarthOrbit for the dwarves
  - seanhunter 1y ago
    …but they orbit too deep, and too greedily.