List of orbits

The following is a list of types of orbits:

Comparison of geostationary Earth orbit with GPS, GLONASS, Galileo and Compass (medium Earth orbit) satellite navigation system orbits with the International Space Station, Hubble Space Telescope and Iridium constellation orbits, and the nominal size of the Earth.[a] The Moon's orbit is around 9 times larger (in radius and length) than geostationary orbit.[b]
Various Earth orbits to scale:
  •   the innermost, the red dotted line represents the orbit of the International Space Station (ISS);
  •   cyan represents low Earth orbit,
  •   yellow represents medium Earth orbit,
  •   The green dashed line represents the orbit of Global Positioning System (GPS) satellites, and
  •   the outermost, the black dashed line represents geosynchronous orbit.

Centric classificationsEdit

For orbits centered about planets other than Earth and Mars, the orbit names incorporating Greek terminology is less commonly used

  • Mercury orbit (Hermocentric or hermiocentric): An orbit around the planet Mercury.
  • Venus orbit (Aphrodiocentric or cytheriocentric): An orbit around the planet Venus.
  • Jupiter orbit (Jovicentric or zenocentric[2]): An orbit around the planet Jupiter.
  • Saturn orbit (Kronocentric[2] or saturnocentric): An orbit around the planet Saturn.
  • Uranus orbit (Oranocentric): An orbit around the planet Uranus.
  • Neptune orbit (Poseidocentric): An orbit around the planet Neptune.[citation needed]

Altitude classifications for geocentric orbitsEdit

  • Low Earth orbit (LEO): geocentric orbits with altitudes below 2,000 km (1,200 mi).[3]
  • Medium Earth orbit (MEO): geocentric orbits ranging in altitude from 2,000 km (1,200 mi) to just below geosynchronous orbit at 35,786 kilometers (22,236 mi). Also known as an intermediate circular orbit. These are used for Global Navigation Satellite System spacecraft, such as GPS, GLONASS, Galileo, BeiDou. GPS satellites orbits at the height of 20,200 kilometers (12,600 mi) with an orbital period of almost 12 hours.[4]
  • Geosynchronous orbit (GSO) and geostationary orbit (GEO) are orbits around Earth matching Earth's sidereal rotation period. Although terms are often used interchangeably, technically a geosynchronous orbit matches the Earth's rotational period, but the definition does not require it to have zero orbital inclination to the equator, and thus is not stationary above a given point on the equator, but may oscillate north and south during the course of a day. Thus, a geostationary orbit is defined as a geosynchronous orbit at zero inclination. Geosynchronous (and geostationary) orbits have a semi-major axis of 42,164 km (26,199 mi).[5] This works out to an altitude of 35,786 km (22,236 mi). Both complete one full orbit of Earth per sidereal day (relative to the stars, not the Sun).
  • High Earth orbit: geocentric orbits above the altitude of geosynchronous orbit (35,786 km or 22,236 mi).[4]

For Earth orbiting satellites below the height of about 800 km, the atmospheric drag is the major orbit perturbing force out of all non-gravitational forces.[6] Above 800 km, solar radiation pressure causes the largest orbital perturbations.[7] However, the atmospheric drag strongly depends on the density of the upper atmosphere, which is related to the solar activity, therefore the height at which the impact of the atmospheric drag is similar to solar radiation pressure varies depending on the phase of the solar cycle.

Inclination classificationsEdit

Directional classificationsEdit

  • Prograde orbit: An orbit that is in the same direction as the rotation of the primary (i.e. east on Earth). By convention, the inclination of a Prograde orbit is specified as an angle less than 90°.
  • Retrograde orbit: An orbit counter to the direction of rotation of the primary. By convention, retrograde orbits are specified with an inclination angle of more than 90°. Apart from those in Sun-synchronous orbit, few satellites are launched into retrograde orbit on Earth because the quantity of fuel required to launch them is greater than for a prograde orbit. This is because when the rocket starts out on the ground, it already has an eastward component of velocity equal to the rotational velocity of the planet at its launch latitude.

Eccentricity classificationsEdit

There are two types of orbits: closed (periodic) orbits, and open (escape) orbits. Circular and elliptical orbits are closed. Parabolic and hyperbolic orbits are open. Radial orbits can be either open or closed.

Synchronicity classificationsEdit

Geostationary orbit as seen from the north celestial pole. To an observer on the rotating Earth, the red and yellow satellites appear stationary in the sky above Singapore and Africa respectively.

Orbits in galaxies or galaxy modelsEdit

Pyramid orbit
  • Box orbit: An orbit in a triaxial elliptical galaxy that fills in a roughly box-shaped region.
  • Pyramid orbit: An orbit near a massive black hole at the center of a triaxial galaxy.[11] The orbit can be described as a Keplerian ellipse that precesses about the black hole in two orthogonal directions, due to torques from the triaxial galaxy.[12] The eccentricity of the ellipse reaches unity at the four corners of the pyramid, allowing the star on the orbit to come very close to the black hole.
  • Tube orbit: An orbit near a massive black hole at the center of an axisymmetric galaxy. Similar to a pyramid orbit, except that one component of the orbital angular momentum is conserved; as a result, the eccentricity never reaches unity.[12]

Special classificationsEdit

Pseudo-orbit classificationsEdit

A diagram showing the five Lagrangian points in a two-body system with one body far more massive than the other (e.g. the Sun and the Earth). In such a system, L3L5 are situated slightly outside of the secondary's orbit despite their appearance in this small scale diagram.

See alsoEdit


  1. ^ Orbital periods and speeds are calculated using the relations 4π2R3 = T2GM and V2R = GM, where R = radius of orbit in metres, T = orbital period in seconds, V = orbital speed in m/s, G = gravitational constant ≈ 6.673×1011 Nm2/kg2, M = mass of Earth ≈ 5.98×1024 kg.
  2. ^ Approximately 8.6 times when the moon is nearest (363,104 km ÷ 42,164 km) to 9.6 times when the moon is farthest (405,696 km ÷ 42,164 km).


  1. ^ "Definition of GALACTOCENTRIC". Retrieved 3 June 2020.
  2. ^ a b Parker, Sybil P. (2002). McGraw-Hill Dictionary of Scientific and Technical Terms Sixth Edition. McGraw-Hill. p. 1772. ISBN 007042313X.
  3. ^ "NASA Safety Standard 1740.14, Guidelines and Assessment Procedures for Limiting Orbital Debris" (PDF). Office of Safety and Mission Assurance. 1 August 1995. p. A-2. Archived from the original (PDF) on 15 February 2013. Low Earth orbit (LEO) – The region of space below the altitude of 2000 km., pages 37–38 (6–1,6–2); figure 6-1.
  4. ^ a b c d "Orbit: Definition". Ancillary Description Writer's Guide, 2013. National Aeronautics and Space Administration (NASA) Global Change Master Directory. Archived from the original on 11 May 2013. Retrieved 29 April 2013.
  5. ^ Vallado, David A. (2007). Fundamentals of Astrodynamics and Applications. Hawthorne, CA: Microcosm Press. p. 31.
  6. ^ Krzysztof, Sośnica (1 March 2015). "Impact of the Atmospheric Drag on Starlette, Stella, Ajisai, and Lares Orbits". Artificial Satellites. 50 (1): 1–18. doi:10.1515/arsa-2015-0001.
  7. ^ Bury, Grzegorz; Sośnica, Krzysztof; Zajdel, Radosław; Strugarek, Dariusz (28 January 2020). "Toward the 1-cm Galileo orbits: challenges in modeling of perturbing forces". Journal of Geodesy. 94 (2): 16. doi:10.1007/s00190-020-01342-2.
  8. ^ Hadhazy, Adam (22 December 2014). "A New Way to Reach Mars Safely, Anytime and on the Cheap". Scientific American. Retrieved 25 December 2014.
  9. ^ Whipple, P. H . (17 February 1970). "Some Characteristics of Coelliptic Orbits – Case 610" (PDF). Bellcom Inc. Washington: NASA. Archived from the original (PDF) on 21 May 2010. Retrieved 23 May 2012.
  10. ^ a b This answer explains why such inclination keeps apsidial drift small:
  11. ^ Merritt and Vasilev, ORBITS AROUND BLACK HOLES IN TRIAXIAL NUCLEI", The Astrophysical Journal 726(2), 61 (2011).
  12. ^ a b Merritt, David (2013). Dynamics and Evolution of Galactic Nuclei. Princeton: Princeton University Press. ISBN 9780691121017.
  13. ^ NASA Shapes Science Plan for Deep-Space Outpost Near the Moon March 2018
  14. ^ a b How a New Orbital Moon Station Could Take Us to Mars and Beyond Oct 2017 video with refs
  15. ^ Angelic halo orbit chosen for humankind's first lunar outpost. European Space Agency, Published by PhysOrg. 19 July 2019.
  16. ^ Halo orbit selected for Gateway space station. David Szondy, New Atlas. 18 July 2019.
  17. ^ Foust, Jeff (16 September 2019). "NASA cubesat to test lunar Gateway orbit". SpaceNews. Retrieved 15 June 2020.
  18. ^ "Asteroid Redirect Mission Reference Concept" (PDF). NASA. Retrieved 14 June 2015.
  19. ^ "About Spitzer: Fast Facts". Caltech. 2008. Archived from the original on 2 February 2007. Retrieved 22 April 2007.
  20. ^ "U.S. Government Orbital Debris Mitigation Standard Practices" (PDF). United States Federal Government. Retrieved 28 November 2013.
  21. ^ Luu, Kim; Sabol, Chris (October 1998). "Effects of perturbations on space debris in supersynchronous storage orbits" (PDF). Air Force Research Laboratory Technical Reports (AFRL-VS-PS-TR-1998-1093). Retrieved 28 November 2013.
  22. ^ Keesey, Lori (31 July 2013). "New Explorer Mission Chooses the 'Just-Right' Orbit". NASA. Retrieved 5 April 2018.
  23. ^ Overbye, Dennis (26 March 2018). "Meet Tess, Seeker of Alien Worlds". The New York Times. Retrieved 5 April 2018.