View source for Astronomy:List of Mars orbiters

{{Short description|List of spacecraft orbiting the planet Mars}}
[[Image:2001_mars_odyssey_wizja.jpg|thumb|250px|Artist's rendering of NASA's ''2001 Mars Odyssey'' orbiting Mars]]

The following table is a list of [[Astronomy:Mars|Mars]] [[Engineering:Orbiter|orbiter]]s, consisting of space probes which were launched from Earth and are currently orbiting [[Astronomy:Mars|Mars]]. As of August 2023, there have been 18 spacecraft missions operating in Mars' orbit, 7 of which are currently active.

==History==

===20th century===
[[File:1972 CPA 4113.jpg|200px|thumb|right|upright|Soviet stamp depicting Mars 2]]
The [[Place:Soviet Union|Soviets]]' [[Astronomy:Mars program|Mars program]] and the {{wipe|United States}}'s [[Astronomy:Mariner program|Mariner program]] became the two first successful space programs that intended to [[Astronomy:Exploration of Mars|explore]] [[Astronomy:Mars|Mars]] through [[Engineering:Orbiter|orbiter]]s. [[Astronomy:Mars 2|Mars 2]], [[Astronomy:Mars 3|Mars 3]] and [[Astronomy:Mariner 9|Mariner 9]] were all launched into space in May 1971, and all entered Mars’ orbit that same year. NASA's Mariner 9 reached the planet's orbit first on November 14, narrowly beating the Soviet's spacecraft amid the space race, and subsequently became the first spacecraft to orbit another planet.<ref>
{{cite book |last=Pyle|first=Rod |title=Destination Mars |year=2012 |publisher=Prometheus Books |isbn=978-1-61614-589-7 |pages=73–78 |quote=''It was the first spacecraft to enter orbit around another world.'' ... [It] continues to orbit Mars to this day, sailing around the planet deaf and dumb in the cold darkness.}}</ref>

Contact with all eight Mars orbiters launched during the 20th century has been lost. NASA's four spacecraft are conjectured to remain in Mars' orbit. Mariner 9, ''[[Astronomy:Viking 1|Viking 1]]'' and ''[[Astronomy:Viking 2|Viking 2]]'' are expected to lower down into the Martian atmosphere by 2022 and either burn up or crash into the planet's surface.<ref>[https://web.archive.org/web/20130514043808/http://www.nasa.gov/offices/oce/appel/ask-academy/issues/volume4/ata_4-9_mariner_9_prt.htm NASA - This Month in NASA History: Mariner 9], November 29, 2011 — Vol. 4, Issue 9 </ref> ''[[Astronomy:Mars Global Surveyor|Mars Global Surveyor]]'' is expected to crash onto the surface of the planet by 2047. The fate of the Soviet's three Mars program orbiters and [[Astronomy:Phobos 2|Phobos 2]] remains unclear, but they are still presumed to be in orbit.<ref>{{cite news |last=Dunn |first=Marcia |url=http://articles.latimes.com/1996-10-27/news/mn-58293_1_mars-pathfinder |title=NASA Takes No Dirty Chances With Mars Rover |work=Los Angeles Times |date=October 27, 1996 |access-date=2015-08-03 |quote=It's expected to orbit Mars for at least 50 years before crashing onto the surface of the planet. }}</ref>

In 1999 the [[Astronomy:Mars Climate Orbiter|Mars Climate Orbiter]] impacted the Martian atmosphere.

===21st century===
[[File:PIA07944 Mars Express Seen by Mars Global Surveyor, Figure 1.jpg|thumb|right|upright|200px|Artist's rendition of Mars Express as seen by NASA's ''Mars Global Surveyor'']]
[[File:PIA07944 Mars Express Seen by Mars Global Surveyor.jpg|thumb|Image of Mars Express in orbit at Mars]]
''[[Astronomy:2001 Mars Odyssey|2001 Mars Odyssey]]'' was launched April 7, 2001 on a [[Engineering:Delta II|Delta II]] rocket and currently holds the record for the longest-surviving continually active spacecraft in orbit around a planet other than Earth at {{Age in years, months and days| year=2001| month=10| day=24}}.<ref>{{cite web|url=https://www.nasa.gov/mission_pages/odyssey/odyssey20101215.html|title=NASA's Odyssey Spacecraft Sets Exploration Record on Mars|work=Press Releases|date=2010-12-15|publisher=JPL, NASA|access-date=2015-11-06}}</ref>

In 2003, the [[Organization:European Space Agency|European Space Agency]] (ESA) launched their first planetary mission with [[Astronomy:Mars Express|Mars Express]] to conduct reconnaissance and exploration of Mars from orbit.<ref>[http://www.esa.int/SPECIALS/Mars_Express/SEMJBQXLDMD_0.html ESA - Mars Express - Mars Express Frequently Asked Questions (FAQs)<!-- Bot generated title -->]</ref> On 12 August 2005, NASA launched ''[[Astronomy:Mars Reconnaissance Orbiter|Mars Reconnaissance Orbiter]]'' (MRO). As MRO entered orbit in 2006, it joined three other active spacecraft which were in Mars' orbit: [[Astronomy:Mars Global Surveyor|Mars Global Surveyor]] (MGS), Mars Express, and ''2001 Mars Odyssey''; at the time, this set a record for the most operational spacecraft in the immediate vicinity of Mars. MGS has since ceased to function.

On November 5, 2013, the [[Astronomy:Mars Orbiter Mission|Mars Orbiter Mission]] (''Mangalyaan-1'') was launched by the [[Astronomy:Indian Space Research Organisation|Indian Space Research Organisation]] (ISRO) as a "technology demonstrator" project. Its secondary goal is to analyze the Martian atmosphere and topography. The orbiter reached Mars orbit on September 24, 2014. Through this mission, ISRO became the first space agency to succeed in its first attempt at a Mars orbiter. The mission is the first successful Asian interplanetary mission.<ref>{{cite web |url=http://www.isro.gov.in/mars/home.aspx |title=ISRO: Mars Orbiter Mission |work=isro.gov.in |url-status=dead |archive-url=https://web.archive.org/web/20131109013110/http://isro.gov.in/mars/home.aspx |archive-date=2013-11-09 }}</ref> Ten days after ISRO's launch, NASA launched their seventh Mars orbiter [[Astronomy:MAVEN|MAVEN]] to study the [[Astronomy:Atmosphere of Mars|Martian atmosphere]]. Its goals include determining how the planet's [[Astronomy:Atmosphere of Mars|atmosphere]] and [[Astronomy:Water on Mars|water]], presumed to have once been substantial, were lost over time.<ref name="NASA-20140921">{{cite web |last=Brown |first=Dwayne |last2=Neal-Jones |first2=Nancy |last3=Zubritsky |first3=Elizabeth |title=NASA's Newest Mars Mission Spacecraft Enters Orbit around Red Planet |url=http://www.jpl.nasa.gov/news/news.php?release=2014-318 |date=September 21, 2014 |work=[[Organization:NASA|NASA]] |access-date=September 22, 2014 }}</ref>

===Fate===
After achieving orbit, functional or not, Mars orbiters have been predicted to remain in orbit for a certain amount of time.<ref>{{cite news |last=Dunn |first=Marcia |url=http://articles.latimes.com/1996-10-27/news/mn-58293_1_mars-pathfinder |title=NASA Takes No Dirty Chances With Mars Rover |work=Los Angeles Times |date=October 27, 1996 |access-date=2015-08-03 |quote=It's expected to orbit Mars for at least 50 years before crashing onto the surface of the planet. }}</ref>

*''[[Astronomy:Viking 1|Viking 1]]'' orbiter, likely to be in orbit as of 2019.<ref name=Jefferson>{{cite conference |url=http://enu.kz/repository/2009/AIAA-2009-6002.pdf |title=An Investigation of the Orbital Status of Viking-1 |first=David C |last=Jefferson |first2=Stuart W |last2=Demcak |first3=Pasquale B |last3=Esposito |first4=Gerhard L |last4=Kruizinga |date=10–13 August 2009 |conference=AIAA Guidance, Navigation, and Control Conference |access-date=31 December 2017 |archive-date=3 January 2017 |archive-url=https://web.archive.org/web/20170103165214/http://enu.kz/repository/2009/AIAA-2009-6002.pdf |url-status=dead }}</ref>
*[[Astronomy:Mariner 9|Mariner 9]] was expected to remain in orbit until approximately 2022, when the spacecraft was projected to enter the Martian atmosphere and either burn up or crash into the planet's surface.<ref>[https://web.archive.org/web/20130514043808/http://www.nasa.gov/offices/oce/appel/ask-academy/issues/volume4/ata_4-9_mariner_9_prt.htm NASA – This Month in NASA History: Mariner 9], November 29, 2011 – Vol. 4, Issue 9 </ref>
*[[Astronomy:Mars Global Surveyor|Mars Global Surveyor]] is predicted to orbit until 2046 (50 years after insertion).<ref>{{cite news |last=Dunn |first=Marcia |url=http://articles.latimes.com/1996-10-27/news/mn-58293_1_mars-pathfinder |title=NASA Takes No Dirty Chances With Mars Rover |work=Los Angeles Times |date=October 27, 1996 |access-date=2015-08-03 |quote=It's expected to orbit Mars for at least 50 years before crashing onto the surface of the planet. }}</ref>

Besides decaying to Mars, a collision with a moon or other spacecraft is also a possibility.<ref>{{Cite news|url=http://spacenews.com/nasa-spacecraft-avoids-potential-collision-with-martian-moon/|title=NASA spacecraft avoids potential collision with Martian moon - SpaceNews.com|date=2017-03-03|work=SpaceNews.com|access-date=2017-12-31|language=en-US}}</ref> In March 2017, ''[[Astronomy:MAVEN|MAVEN]]'' had to change its orbit to avoid colliding with Phobos, and with an increasing number of spacecraft at Mars this risk increases.<ref>{{Cite news|url=http://spacenews.com/nasa-spacecraft-avoids-potential-collision-with-martian-moon/|title=NASA spacecraft avoids potential collision with Martian moon - SpaceNews.com|date=2017-03-03|work=SpaceNews.com|access-date=2017-12-31|language=en-US}}</ref> The ''[[Astronomy:Mars Global Surveyor|Mars Global Surveyor]]'' is still being tracked, although it is no longer functioning.<ref>{{Cite news|url=http://spacenews.com/nasa-spacecraft-avoids-potential-collision-with-martian-moon/|title=NASA spacecraft avoids potential collision with Martian moon - SpaceNews.com|date=2017-03-03|work=SpaceNews.com|access-date=2017-12-31|language=en-US}}</ref>

==Table of objects==
{| class="wikitable floatright" style="width:20%; text-align:center;"
 |-
 ! style="background:" colspan="2" | Color legend
 |-
 | style="background:#FF8A99; width:20px;" |
 | Destroyed
 |-
 | style="background:lightyellow; width:20px;" |
 | Loss of contact
 |-
 | style="background:#CCFFD9; width:20px;" |
 | Operational
 |}

Note that days active category does not necessarily equate to time in orbit, for example Mars Global Surveyor is expected remain in Mars orbit for 50 years after its arrival.<ref>{{cite news |last=Dunn |first=Marcia |url=http://articles.latimes.com/1996-10-27/news/mn-58293_1_mars-pathfinder |title=NASA Takes No Dirty Chances With Mars Rover |work=Los Angeles Times |date=October 27, 1996 |access-date=2015-08-03 |quote=It's expected to orbit Mars for at least 50 years before crashing onto the surface of the planet. }}</ref> The detection of derelict spacecraft in Mars orbit has some interest due to the minute risk of collision with such a spacecraft.  One example of this is a  proposal to use the Optical Navigation Camera on the Mars Reconnaissance Orbiter to search for small moons, dust rings, and old orbiters.<ref>[http://www.lpi.usra.edu/meetings/marsconcepts2012/pdf/4337.pdf M. Adler, et al. – Use of MRO Optical Navigation Camera .. (2012)]</ref>
{{clear}}
{|class="wikitable sortable" style="width:100%; text-align:center;"
|- class="is-sticky"
! '''Artificial object'''
! '''Agency'''
! '''Launch date'''
! '''Entered orbit'''
! '''Days active'''
! class="unsortable"| '''Image'''
|-
| {{partial|{{hs|2}}[[Astronomy:Mars 2|Mars 2]]}}
| {{flagicon|USSR}} [[Company:Lavochkin|Lavochkin]]
| 19 May 1971
| 27 November 1971
| {{ntsh|10}} {{age in days|27 November 1971|22 August 1972}} days
| |[[File:Mars3 iki.jpg|120px]]
|-
| {{partial|{{hs|2}}[[Astronomy:Mars 3|Mars 3]]}}
| {{flagicon|USSR}} [[Company:Lavochkin|Lavochkin]]
| 28 May 1971
| 2 December 1971
| {{ntsh|11}} {{age in days|2 December 1971|22 August 1972}} days
| |[[File:Mars3 iki.jpg|120px]]
|-
| {{partial|{{hs|2}}[[Astronomy:Mariner 9|Mariner 9]]}}
| {{flagicon|USA}} [[Organization:NASA|NASA]]
| 30 May 1971
| 14 November 1971
| {{ntsh|9}} {{age in days|14 November 1971|27 October 1972}} days
| |[[File:Mariner09.jpg|120px]]
|-
| {{partial|{{hs|2}}[[Astronomy:Mars 5|Mars 5]]}}
| {{flagicon|USSR}} [[Company:Lavochkin|Lavochkin]]
| 25 July 1973
| 12 February 1974
| {{ntsh|13}} {{age in days|12 February 1974|28 February 1974}} days
| |[[File:Mars3 iki.jpg|120px]]
|-
| {{partial|{{hs|2}}''[[Astronomy:Viking 1|Viking 1]]''}}
| {{flagicon|USA}} [[Organization:NASA|NASA]]
| 20 August 1975
| 19 June 1976
| {{ntsh|5}} {{age in days|19 June 1976|17 August 1980}} days
| |[[File:Viking spacecraft.jpg|120px]]
|-
| {{partial|{{hs|2}}''[[Astronomy:Viking 2|Viking 2]]''}}
| {{flagicon|USA}} [[Organization:NASA|NASA]]
| 9 September 1975
| 7 August 1976
| {{ntsh|6}} {{age in days|7 August 1976|25 July 1978}} days
| |[[File:Viking spacecraft.jpg|120px]]
|-
| {{partial|{{hs|2}}[[Astronomy:Phobos 2|Phobos 2]]}}
| {{flagicon|USSR}} [[Company:Lavochkin|Lavochkin]]
| 12 July 1988
| 29 January 1989
| {{ntsh|12}} {{age in days|29 January 1989|27 March 1989}} days
| |[[File:Phobos Marte.jpg|120px]]
|-
| {{partial|{{hs|2}}[[Astronomy:Mars Global Surveyor|Mars Global Surveyor]]}}
| {{flagicon|USA}} [[Organization:NASA|NASA]]
| 7 November 1996
| 12 September 1997
| {{ntsh|4}} {{age in days|12 September 1997|2 November 2006}} days
| |[[File:Mars global surveyor.jpg|120px]]
|-
| {{yes2|{{nowrap|{{hs|3}}''[[Astronomy:2001 Mars Odyssey|2001 Mars Odyssey]]''}}}}
| {{flagicon|USA}} [[Organization:NASA|NASA]]
| 7 April 2001
| 24 October 2001
| {{ntsh|1}} {{age in days|24 October 2001}} days
| |[[File:2001 mars odyssey wizja.jpg|120px]]
|-
| {{yes2|{{nowrap|{{hs|3}}''[[Astronomy:Mars Express|Mars Express]]''}}}}
| [[File:ESA logo simple.svg|20px|link=European Space Agency|European Space Agency]] ESA
| 2 June 2003
| 25 December 2003
| {{ntsh|2}} {{age in days|25 December 2003}} days
| |[[File:Mars-express-volcanoes-sm.jpg|120px]]
|-
| {{yes2|{{nowrap|{{hs|3}}''[[Astronomy:Mars Reconnaissance Orbiter|Mars Reconnaissance Orbiter]]''}}}}
| {{flagicon|USA}} [[Organization:NASA|NASA]]
| 12 August 2005
| 10 March 2006
| {{ntsh|3}} {{age in days|10 March 2006}} days
| |[[File:Mars Reconnaissance Orbiter.jpg|120px]]
|-
| {{partial|{{hs|2}} [[Astronomy:Mars Orbiter Mission|Mars Orbiter Mission]] <br />(''Mangalyaan'')}}
| {{flagicon|India}} [[Astronomy:ISRO|ISRO]]
| 5 November 2013
| 24 September 2014
| {{ntsh|8}} {{age in days|24 September 2014}} days
| |[[File:Mars Orbiter Mission - India - ArtistsConcept.jpg|120px]]
|-
| {{yes2|{{nowrap|{{hs|3}}[[Astronomy:MAVEN|MAVEN]]}}}}
| {{flagicon|USA}} [[Organization:NASA|NASA]]
| 18 November 2013
| 22 September 2014
| {{ntsh|7}} {{age in days|22 September 2014}} days
| |[[File:Mars-MAVEN-Orbiter-20140921.jpg|120px]]
|-
| {{yes2|{{nowrap|{{hs|3}} [[Astronomy:ExoMars Trace Gas Orbiter|ExoMars Trace Gas Orbiter]] }}}}
| [[File:ESA logo simple.svg|20px|link=European Space Agency|European Space Agency]] ESA<br />{{flagicon|Russia}} [[Company:Roscosmos|Roscosmos]]
| {{ntsh|8}} 14 March 2016 
|  19 October 2016
| {{age in days|19 October 2016}} days
|[[File:ExoMars Trace Gas Orbiter.jpg|120px]]
|-
| {{yes2|{{nowrap|{{hs|3}} [[Astronomy:Emirates Mars Mission|Emirates Mars Mission]] <br />(''Hope'') }}}}
| {{flagicon|UAE}} [[Organization:United Arab Emirates Space Agency|UAESA]]
| {{ntsh|8}} 19 July 2020 
|  9 February 2021
| {{age in days|9 february 2021}} days
|
|-
| {{yes2|{{nowrap|{{hs|3}} Tianwen 1 <br />orbiter  }}}}
| {{flagicon|CHN}} CNSA
| {{ntsh|8}} 23 July 2020 
|  10 February 2021
| {{age in days|10 february 2021}} days
|
|-
| {{partial|{{hs|2}} Tianwen 1 <br />Deployable Camera 2}}
| {{flagicon|CHN}} CNSA
| {{ntsh|8}} 23 July 2020 
|  10 February 2021 (released on 31 December 2021)
| <1 day
|
|}

==See also==
* [[Engineering:Lists of spacecraft|Lists of spacecraft]]
* [[Astronomy:Exploration of Mars|Exploration of Mars]]
* [[Astronomy:List of missions to Mars|List of missions to Mars]]
* [[Engineering:Robotic spacecraft|Robotic spacecraft]]
* [[Engineering:Timeline of artificial satellites and space probes|Timeline of artificial satellites and space probes]]
* Timeline of planetary exploration

==References==
{{Reflist|30em}}

{{Spacecraft by destination}}
{{Mars spacecraft}}

{{DEFAULTSORT:Mars orbiters}}
[[Category:Missions to Mars]]
[[Category:Orbiters (space probe)|*]]
[[Category:Lists of spacecraft]]

{{Sourceattribution|List of Mars orbiters}}