Editing Graveyard orbit

{{distinguish|Spacecraft cemetery}}{{Short description|Spacecraft end-of-life orbit}}
{{comparison satellite navigation orbits}}
[[File:Animation of Spaceway around Earth - ECEF.gif|thumb|An example of a graveyard orbit – [[ECEF|Earth fixed frame]]<br>{{legend2| Royalblue | Earth}}{{·}}{{legend2| magenta | [[Spaceway-1]]}}{{·}}{{legend2| Lime | [[Spaceway-2]]}}{{·}}{{legend2| Cyan | [[Spaceway-3]]}}]]
A '''graveyard orbit''', also called a '''junk orbit''' or '''disposal orbit''', is an [[Orbit (physics)|orbit]] that lies away from common operational orbits. One significant graveyard orbit is a [[supersynchronous orbit]] well beyond [[geosynchronous orbit]].<!-- as of 2017, there are no common supersynchronous graveyard orbits in common use around non-terran celestial bodies --> Some satellites are moved into such orbits at the end of their [[Spacecraft retirement|operational life]] to reduce the probability of colliding with operational [[spacecraft]] and generating [[space debris]].

==Overview==
A graveyard orbit is used when the change in velocity required to perform a de-orbit [[Orbital maneuver|maneuver]] is too large. De-orbiting a [[geostationary satellite]] requires a [[delta-v]] of about {{convert|1500|m/s}}, whereas re-orbiting it to a graveyard orbit only requires about {{convert|11|m/s}}.<ref>{{Cite web |url=http://www.patentgenius.com/patent/5651515.html |title=Method for re-orbiting a dual-mode propulsion geostationary spacecraft – Patent # 5651515 – PatentGenius<!-- Bot generated title --> |access-date=2012-10-28 |archive-url=https://web.archive.org/web/20131110184645/http://www.patentgenius.com/patent/5651515.html |archive-date=2013-11-10 |url-status=dead }}</ref>

For satellites in [[geostationary orbit]] and [[geosynchronous orbit]]s, the graveyard orbit is a few hundred [[kilometer]]s beyond the operational orbit. The transfer to a graveyard orbit beyond geostationary orbit requires the same amount of fuel as a satellite needs for about three months of [[Orbital station-keeping|stationkeeping]]. It also requires a reliable [[Spacecraft attitude control|attitude control]] during the transfer maneuver. While most satellite operators plan to perform such a maneuver at the end of their satellites' operational lives, through 2005 only about one-third succeeded.<ref>{{Cite web|url=http://www.esa.int/Enabling_Support/Operations/Space_debris_mitigation_the_case_for_a_code_of_conduct|title=ESA – Space debris mitigation: the case for a code of conduct|website=www.esa.int}}</ref> Given the economic value of the positions at geosynchronous altitude, unless premature spacecraft failure precludes it, satellites are moved to a graveyard orbit prior to decommissioning.<ref>{{cite journal|title=End-of-Life Disposal of Geostationary Satellites|url=https://adsabs.harvard.edu/full/2005ESASP.587..373J|last1=Jehn|first1=R.|last2=Agapov|first2=V.|last3=Hernández|first3=C.|journal=Proceedings of the 4th European Conference on Space Debris (ESA SP-587)|date=20 April 2005|volume=587 |publisher=ESA/ESOC|page=373|bibcode=2005ESASP.587..373J |access-date=November 6, 2022}}</ref><ref>{{cite web |last=Johnson|first=Nicholas |title=Broadcast 1666 (Special Edition) – Topic: Space debris issues |date=2011-12-05 |url=http://www.thespaceshow.com/show/05-dec-2011/broadcast-1666-special-edition |type=podcast |at=1:03:05–1:06:20 |publisher=[[The Space Show]] |editor-first=David |editor-last=Livingston |access-date=2015-01-05 }}</ref>

According to the [[Inter-Agency Space Debris Coordination Committee]] (IADC) the minimum recommended [[perigee]] [[altitude]] <math>\Delta{H}</math> beyond the [[geostationary orbit]] is<ref>{{Cite web |url=http://www.iadc-online.org/Documents/IADC-UNCOPUOS-final.pdf |title=Report of the IADC Activities on Space Debris Mitigation Measures|at=Guideline 5.3.1: Post mission disposal for geosynchronous region|access-date=2015-03-07 |archive-url=https://web.archive.org/web/20150402103645/http://www.iadc-online.org/Documents/IADC-UNCOPUOS-final.pdf |archive-date=2015-04-02 |url-status=usurped }}</ref>

:<math>\Delta{H} = 235\mbox{ km} + C_\mathrm{R} \frac{A \left[ \mathrm{m}^2 \right]}{m \left[ \mathrm{kg} \right]} \cdot 1000\mbox{ km}</math>
where
:<math>C_\mathrm{R}</math> is the satellite's solar [[radiation pressure coefficient]], whose value is between 1 (for absorbtion) and 2 (for specular reflection), 
:<math>A</math> is its aspect area,
:<math>m</math> is its mass.

This formula includes {{convert|200|km}} for the GEO-protected zone to also permit orbit maneuvers in GEO without interference with the graveyard orbit. Another {{convert|35|km}} of [[tolerance (engineering)|tolerance]] must be allowed for the effects of [[gravitational perturbation]]s (primarily solar and lunar). The remaining part of the equation considers the effects of the [[solar radiation pressure]], which depends on the physical parameters of the satellite.

In order to obtain a license to provide [[telecommunication]]s services in the United States, the [[Federal Communications Commission]] (FCC) requires all geostationary satellites launched after March 18, 2002, to commit to moving to a graveyard orbit at the end of their operational lives.<ref>{{cite web|url=http://www.space.com/spacenews/businessmonday_040628.html |title=FCC Enters Orbital Debris Debate |website=[[Space.com]] |url-status=dead |archive-url=https://web.archive.org/web/20050308040713/http://www.space.com/spacenews/businessmonday_040628.html |archive-date=March 8, 2005 }}</ref> U.S. government regulations require a boost, <math>\Delta{H}</math>, of about {{convert|300|km|0|abbr=on}}.<ref>{{cite web | url=http://orbitaldebris.jsc.nasa.gov/library/USG_OD_Standard_Practices.pdf | title=US Government Orbital Debris Standard Practices}}</ref> In 2023 [[Dish Network|DISH]] received the first-ever fine by the FCC for failing to de-orbit its [[EchoStar VII]] satellite according to the terms of its license.<ref>{{cite news |last1=Shepardson |first1=David |title=DISH gets first-ever space debris fine over EchoStar-7 |url=https://www.reuters.com/technology/space/dish-gets-first-ever-space-debris-fine-over-echostar-7-2023-10-02/ |access-date=3 October 2023 |work=Reuters |date=2 October 2023}}</ref>

A spacecraft moved to a graveyard orbit will typically be [[Passivation (spacecraft)|passivated]].

Uncontrolled objects in a near geostationary [Earth] orbit (GEO) exhibit a 53-year cycle of orbital inclination<ref name=Anderson2015>{{Cite conference|url=http://hanspeterschaub.info/Papers/Anderson2015c.pdf|title=Operational Considerations of GEO Debris Synchronization Dynamics|first1=Paul|last1=Anderson|display-authors=etal|conference=66th [[International Astronautical Congress]]|location=Jerusalem, Israel|date=2015|id=IAC-15,A6,7,3,x27478}}</ref> due to the interaction of the Earth's tilt with the lunar orbit. The orbital inclination varies ± 7.4°, at up to 0.8°pa.<ref name=Anderson2015/>{{rp|3}}

== Disposal orbit ==

While the standard geosynchronous satellite graveyard orbit results in an expected [[orbital lifetime]] of millions of years, the increasing number of satellites, the launch of microsatellites, and the [[FCC]] approval of large [[Satellite internet constellation|megaconstellations]] of thousands of [[artificial satellites|satellites]] for launch by 2022 necessitates new approaches for deorbiting to assure earlier removal of the objects once they have reached end-of-life. Contrary to GEO graveyard orbits requiring three months' worth of fuel ([[delta-V]] of 11&nbsp;m/s) to reach, large satellite networks in LEO require orbits that passively decay into the Earth's atmosphere. For example, both [[OneWeb]] and [[SpaceX]] have committed to the FCC [[regulatory authorities]] that decommissioned satellites will decay to a lower orbit{{snd}}a '''disposal orbit'''{{snd}}where the satellite [[orbital altitude]] would decay due to [[atmospheric drag]] and then naturally [[atmospheric reentry|reenter]] the atmosphere and burn up within one year of end-of-life.<ref name=ars20171004>
{{cite news |last=Brodkin|first=Jon |url=https://arstechnica.com/information-technology/2017/10/spacex-and-oneweb-broadband-satellites-raise-fears-about-space-debris/ |title=SpaceX and OneWeb broadband satellites raise fears about space debris |work=[[Ars Technica]] |date=4 October 2017 |access-date=28 April 2019 }}</ref>

==See also==
* [[List of orbits]]
* [[SNAP-10A]]&nbsp;– nuclear reactor satellite, remaining in a {{convert|700|nmi|adj=on}} sub-synchronous Earth orbit for an expected 4,000 years
* [[Spacecraft cemetery]], in the Pacific Ocean

==Notes==
{{notelist}}

==References==
{{Reflist}}

{{orbits|state=expanded}}

[[Category:Derelict satellites|derelict]]
[[Category:Astrodynamics]]
[[Category:Earth orbits]]
[[Category:Spacecraft retirement]]