Editing Low Earth orbit (section)

==Use==
[[File:Sunrise To Sunset Aboard The ISS.OGG|thumb|Roughly half an orbit of the [[International Space Station]]]]

A low Earth orbit requires the lowest amount of energy for satellite placement. It provides high bandwidth and low communication [[latency (engineering)|latency]]. Satellites and space stations in LEO are more accessible for crew and servicing.

Since it requires less [[energy]] to place a satellite into a LEO, and a satellite there needs less powerful amplifiers for successful transmission, LEO is used for many communication applications, such as the [[Iridium Communications|Iridium phone system]]. Some [[communication satellite]]s use much higher [[geostationary orbit]]s and move at the same angular velocity as the Earth as to appear stationary above one location on the planet.

=== Disadvantages ===
Unlike [[geosynchronous satellite|geosynchronous satellites]], satellites in low orbit have a small [[field of view]] and can only observe and communicate with a fraction of the Earth at a given time. This means that a large network (or [[Satellite constellation|constellation]]) of satellites is required to provide continuous coverage.

Satellites at lower altitudes of orbit are in the atmosphere and suffer from rapid [[orbital decay]], requiring either periodic re-boosting to maintain stable orbits, or the launching of replacements for those that re-enter the atmosphere. The effects of adding such quantities of vaporized metals to Earth's [[stratosphere]] are potentially of concern but currently unknown.<ref>{{cite web | url=https://www.scientificamerican.com/article/space-junk-is-polluting-earths-stratosphere-with-vaporized-metal/ | title=Space Junk is Polluting Earth's Stratosphere with Vaporized Metal | website=[[Scientific American]] }}</ref>

===Examples===
* The [[International Space Station]] is in LEO about {{convert|400|to|420|km}} above the Earth's surface.<ref>{{cite web | url=http://www.nasa.gov/mission_pages/station/expeditions/expedition26/iss_altitude.html | title=Higher Altitude Improves Station's Fuel Economy | publisher=NASA | access-date=2013-02-12 | archive-date=2015-05-15 | archive-url=https://web.archive.org/web/20150515050746/http://www.nasa.gov/mission_pages/station/expeditions/expedition26/iss_altitude.html | url-status=live }}</ref> The station’s orbit decays by about {{cvt|2|km/month|mi/month}} and consequently needs re-boosting a few times a year.
* The [[Iridium satellite constellation|Iridium telecom satellites]] orbit at about {{convert|780|km|mi|abbr=on}}.
* [[Earth observation satellite]]s, also known as [[remote sensing]] satellites, including [[spy satellite]]s and other [[Earth imaging]] satellites, use LEO as they are able to see the surface of the Earth more clearly by being closer to it. A majority of artificial [[satellite]]s are placed in LEO.<ref>{{Cite web|title = NASA Earth Observatory|url = http://earthobservatory.nasa.gov/Features/OrbitsCatalog/|website = earthobservatory.nasa.gov|date = 2009-09-04|access-date = 2015-11-28|language = en|first = Riebeek|last = Holli|archive-date = 2018-05-27|archive-url = https://web.archive.org/web/20180527202627/https://earthobservatory.nasa.gov/Features/OrbitsCatalog/|url-status = live}}</ref> Satellites can also take advantage of consistent lighting of the surface below via [[Sun-synchronous orbit|Sun-synchronous LEO orbits]] at an altitude of about {{convert|800|km|mi|-1|abbr=on}} and near polar inclination. [[Envisat]] (2002–2012) is one example.
* The [[Hubble Space Telescope]] orbits at about {{convert|540|km|mi|abbr=on}} above Earth.
* [[Satellite internet constellation]]s such as [[Starlink]].
* The Chinese [[Tiangong space station]] was launched in April 2021 and currently orbits between {{convert|340|and|450|km|abbr=on}} above the Earth's surface. 
* The [[gravimetry]] mission [[GRACE-FO]] orbits at about {{convert|500|km|mi|abbr=on}} as did its predecessor, [[Gravity Recovery and Climate Experiment|GRACE]].

==== Former ====

* [[GOCE]] (2009-2013), an [[ESA]] gravimetry mission, orbited at about 255 km (158 mi).

* [[Super Low Altitude Test Satellite]] (2017-2019), nicknamed ''Tsubame'', orbited at {{cvt|167.4|km}}, the lowest altitude ever among Earth observation satellites.<ref>{{Cite news |date=2019-12-30 |title=Japan's low altitude satellite Tsubame registered in Guinness World Records |url=https://www.japantimes.co.jp/news/2019/12/30/national/japan-low-altitude-satellite-tsubame/ |access-date=2024-06-25 |work=The Japan Times}}</ref>

==== In fiction ====
* In the film ''[[2001: A Space Odyssey (film)|2001: A Space Odyssey]]'', Earth's transit station ("Space Station V") "orbited 300 km above Earth".<ref>{{Cite web |title=Space station from 2001: A Space Odyssey |url=https://www.esa.int/ESA_Multimedia/Images/2012/01/Space_station_from_2001_A_Space_Odyssey}}</ref>