Medium Earth orbit

Clickable image, highlighting medium altitude orbits around Earth,[a] from Low Earth to the lowest High Earth orbit (geostationary orbit and its graveyard orbit, at one ninth of the Moon's orbital distance),[b] with the Van Allen radiation belts and the Earth to scale
To-scale diagram of low, medium, and high Earth orbits
Space of Medium Earth orbits (MEO) as pink area, with Earth and the distance of the orbit of the Moon for reference and to scale.

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) – between 2,000 and 35,786 km (1,243 and 22,236 mi) above sea level.[1]

The boundary between MEO and LEO is an arbitrary altitude chosen by accepted convention, whereas the boundary between MEO and HEO is the particular altitude of a geosynchronous orbit, in which a satellite takes 24 hours to circle the Earth, the same period as the Earth’s own rotation. All satellites in MEO have an orbital period of less than 24 hours, with the minimum period (for a circular orbit at the lowest MEO altitude) about 2 hours.[2]

Satellites in MEO orbits are perturbed by solar radiation pressure, which is the dominating non-gravitational perturbing force.[3] Other perturbing forces include: Earth's albedo, navigation antenna thrust, and thermal effects related to heat re-radiation.

The MEO region includes the two zones of energetic charged particles above the equator known as the Van Allen radiation belts, which can damage satellites’ electronic systems without special shielding.[4]

A medium Earth orbit is sometimes called mid Earth orbit[1] or intermediate circular orbit (ICO).[2]


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  1. ^ a b Catalog of Earth Satellite Orbits. NASA Earth Observatory. 4 September 2009. Accessed 2 May 2021.
  2. ^ a b "Definitions of geocentric orbits from the Goddard Space Flight Center". User support guide: platforms. NASA Goddard Space Flight Center. Archived from the original on 27 May 2010. Retrieved 8 July 2012.
  3. ^ Bury, Grzegorz; Sośnica, Krzysztof; Zajdel, Radosław; Strugarek, Dariusz (February 2020). "Toward the 1-cm Galileo orbits: challenges in modeling of perturbing forces". Journal of Geodesy. 94 (2): 16. Bibcode:2020JGeod..94...16B. doi:10.1007/s00190-020-01342-2.
  4. ^ "Popular Orbits 101". Aerospace Security. 26 October 2020. Accessed 2 May 2021.