Editing 2001 Mars Odyssey (section)

== Mission ==
[[Image:Odyssey summary br.jpg|thumb|right|250px|Summary of ''Mars Odyssey'' mission start]]
[[File:2001 Mars Odyssey being encapsulated in Delta II rocket fairing (KSC-01PP-0699).jpg|thumb|The spacecraft encapsulated in Delta II rocket fairing]]

''Mars Odyssey'' launched from [[Cape Canaveral Air Force Station|Cape Canaveral]] on April 7, 2001, and arrived at Mars about 200 days later on October 24. Upon arrival, the spacecraft's main engine fired<ref name=":0">{{Cite web|title=NASA Facts: 2001 Mars Odyssey|url=https://mars.nasa.gov/odyssey/files/odyssey/Odyssey0302.pdf|url-status=live|website=[[NASA]]|archive-url=https://web.archive.org/web/20150905091733/http://mars.nasa.gov/odyssey/files/odyssey/Odyssey0302.pdf |archive-date=September 5, 2015 }}</ref> in order to decelerate, which allowed it to be captured into orbit around Mars. ''Odyssey'' then spent about 76 days [[aerobraking]], using [[aerodynamic drag]] from the upper reaches of the Martian atmosphere to gradually slow down and reduce and circularize its orbit.<ref name=":0" /> By planning to use the atmosphere of Mars to slow the spacecraft in its orbit rather than firing its engine or thrusters, ''Odyssey'' did not need an additional 200 kilograms (440 lb) of propellant on board. This reduction in spacecraft weight allowed the mission to be launched on a Delta II 7925 launch vehicle, rather than a larger, more expensive launcher.<ref>{{Cite press release|url=http://mars.jpl.nasa.gov/odyssey/newsroom/pressreleases/02jan11.html| title=Mars Odyssey Mission Status |date=11 January 2002| publisher=[[NASA Jet Propulsion Laboratory]]}}</ref>

Aerobraking ended in January 2002, and Odyssey began its science mapping mission on February 19, 2002. ''Odyssey''{{'}}s original, nominal mission lasted until August 2004, but repeated mission extensions have kept the mission active.<ref>{{cite web|url=http://mars.nasa.gov/odyssey/mission/timeline/|title=Mission Timeline – Mars Odyssey|date=April 16, 2024 | publisher=NASA Jet Propulsion Laboratory}}</ref>

The payload's MARIE radiation experiment stopped taking measurements after a large solar event bombarded the ''Odyssey'' spacecraft on October 28, 2003. Engineers believe the most likely cause is that a computer chip was damaged by a solar particle smashing into the MARIE computer board.<ref name="marie">{{cite web |title=MARIE |url=https://mars.nasa.gov/odyssey/mission/instruments/marie/ |website=2001 Mars Odyssey |date=December 4, 2017 |publisher=[[NASA]] |access-date=10 May 2021 |archive-url=https://web.archive.org/web/20210510210531/https://mars.nasa.gov/odyssey/mission/instruments/marie/ |archive-date=10 May 2021 |url-status=live}}</ref>

About 85% of images and other data from NASA's twin [[Mars Exploration Rover]]s, ''[[Spirit rover|Spirit]]'' and ''[[Opportunity rover|Opportunity]]'', have reached Earth via communications relay by ''Odyssey''.<ref>{{Cite web|url=https://mars.nasa.gov/odyssey/mission/timeline/communicationsrelay/|title=Communications Relay – Mars Odyssey|last=NASA|first=JPL|website=mars.nasa.gov|access-date=October 31, 2018}}</ref> The orbiter helped analyze potential landing sites for the rovers and performed the same task for NASA's [[Phoenix mission]], which landed on Mars in May 2008. ''Odyssey'' aided NASA's ''[[Mars Reconnaissance Orbiter]]'', which reached Mars in March 2006, by monitoring atmospheric conditions during months when the newly arrived orbiter used aerobraking to alter its orbit into the desired shape.<ref>{{Cite web |title=Mars Odyssey Begins Overtime After Successful Mission |url=https://www.jpl.nasa.gov/news/mars-odyssey-begins-overtime-after-successful-mission |access-date=2022-06-24 |website=NASA Jet Propulsion Laboratory (JPL) |language=en-US}}</ref>

''Odyssey'' is in a [[Sun-synchronous orbit]],<ref name="NASA Science 2001 e840">{{cite web | title=Mars Odyssey | website=NASA Science | date=October 24, 2001 | url=https://science.nasa.gov/mission/odyssey/ | access-date=March 20, 2024}}</ref> which provides consistent lighting for its photographs. On September 30, 2008 (sol {{age in sols|2001|10|24|2008|09|30}}) the spacecraft altered its orbit to gain better sensitivity for its infrared mapping of Martian minerals. The new orbit eliminated the use of the gamma ray detector, due to the potential for overheating the instrument at the new orbit.<ref name="odyssey alters orbit">{{cite web |last1=Martinez |first1=Carolina |last2=Webster |first2=Guy |title=NASA's Mars Odyssey Alters Orbit to Study Warmer Ground |url=https://www.jpl.nasa.gov/news/nasas-mars-odyssey-alters-orbit-to-study-warmer-ground |website=JPL News |publisher=[[Jet Propulsion Laboratory|JPL]] |access-date=10 May 2021 |archive-url=https://web.archive.org/web/20210510211844/https://www.jpl.nasa.gov/news/nasas-mars-odyssey-alters-orbit-to-study-warmer-ground |archive-date=10 May 2021 |location=[[Pasadena, California]] |date=22 June 2009 |url-status=live}}</ref>

By December 15, 2010, it broke the record for longest serving spacecraft at Mars, with 3,340 days of operation.<ref name="jpl-1091">{{cite web | url=http://mars.jpl.nasa.gov/odyssey/news/whatsnew/index.cfm?FuseAction=ShowNews&NewsID=1091 | title=NASA's Odyssey Spacecraft Sets Exploration Record on Mars | work=Press Releases | date=December 15, 2010 | publisher=JPL, NASA | archive-url=https://web.archive.org/web/20110425065346/http://mars.jpl.nasa.gov/odyssey/news/whatsnew/index.cfm?FuseAction=ShowNews&NewsID=1091 | archive-date=April 25, 2011 | url-status=live }}</ref><ref>{{Cite web |last=Howell |first=Elizabeth |date=July 23, 2018 |title=Mars Odyssey: Record-Breaking Mission to Mars |url=https://www.space.com/18270-mars-odyssey.html |access-date=March 13, 2024 |website=space.com}}</ref> 

The orbiter's orientation is controlled by a set of three [[reaction wheels]] and a spare. When one failed in June 2012, the fourth was spun up and successfully brought into service. Since July 2012, ''Odyssey'' has been back in full, nominal operation mode following three weeks of 'safe' mode on remote maintenance.<ref name="jpl_1242">{{cite web | url=http://mars.jpl.nasa.gov/odyssey/news/whatsnew/index.cfm?FuseAction=ShowNews&NewsID=1242 | title=Longest-Lived Mars Orbiter Is Back in Service | date=June 27, 2012 | work=Status Reports | publisher=JPL | archive-url=https://web.archive.org/web/20120703221048/http://mars.jpl.nasa.gov/odyssey/news/whatsnew/index.cfm?FuseAction=ShowNews&NewsID=1242 | archive-date=July 3, 2012 | url-status=live }}</ref><ref>{{Cite web|url=https://mars.nasa.gov/odyssey/mission/spacecraft/parts/guidancenavcontrol/|title=Guidance, Navigation, and Control – Mars Odyssey|last=NASA|first=JPL|website=mars.nasa.gov|date=December 4, 2017 |access-date=October 31, 2018}}</ref>

''Mars Odyssey''{{'}}s THEMIS instrument was used to help select a landing site for the [[Mars Science Laboratory]] (MSL).<ref name="themis_sites">{{cite web | url=http://themis.asu.edu/landingsites | title=THEMIS Support for MSL Landing Site Selection | work=THEMIS | date=July 28, 2006 | publisher=Arizona State University | archive-url=https://web.archive.org/web/20060814062323/http://themis.asu.edu/landingsites/ | archive-date=August 14, 2006 | url-status=live }}</ref> Several days before MSL's landing in August 2012, ''Odyssey''{{'}}s orbit was altered to ensure that it would be able to capture signals from the rover during its first few minutes on the Martian surface.<ref name="latimes">{{cite web | url=https://www.latimes.com/local/la-xpm-2012-aug-07-la-sci-mars-seven-minutes-20120807-story.html | title=Curiosity's perilous landing? 'Cleaner than any of our tests' | work=Los Angeles Times | date=August 7, 2012 | first=Scott | last=Gold | archive-url=https://web.archive.org/web/20120809094601/http://articles.latimes.com/2012/aug/07/science/la-sci-mars-seven-minutes-20120807 | archive-date=August 9, 2012 | url-status=live }}</ref>   ''Odyssey'' also acted as a relay for UHF radio signals from the (MSL) rover ''[[Curiosity rover|Curiosity]]''.<ref>{{cite web |title=Mars Science Laboratory Landing |url=https://mars.nasa.gov/internal_resources/785/ |publisher=NASA/JPL |access-date=22 January 2021 |date=July 2012}}</ref> Because ''Odyssey'' is in a [[Sun-synchronous orbit]],<ref name="NASA Science 2001 e840" /> it passes over ''Curiosity''{{'}}s location twice per day, enabling regular contact with Earth.<ref name="Howell 2012 a497">{{cite web | last=Howell | first=Elizabeth | title=How NASA's New Mars Rover Will Phone Home | website=Space.com | date=August 3, 2012 | url=https://www.space.com/16893-mars-rover-curiosity-brain.html | access-date=March 20, 2024}}</ref>

On February 11, 2014, mission control accelerated ''Odyssey''{{'}}s drift toward a morning-daylight orbit to "enable observation of changing ground temperatures after sunrise and after sunset in thousands of places on Mars". The orbital change occurred gradually until November 2015.<ref name="drift">{{cite news | last=Staff | title=NASA Moves Longest-Serving Mars Spacecraft for New Observations | date=February 12, 2014 | publisher=Jet Propulsion Laboratory | url=http://www.jpl.nasa.gov/news/news.php?release=2014-047&2 | work=Press Releases | archive-url=https://web.archive.org/web/20140226161657/http://www.jpl.nasa.gov/news/news.php?release=2014-047&2 | archive-date=February 26, 2014 | url-status=live }}</ref> Those observations could yield insight about the composition of the ground and about temperature-driven processes, such as [[Seasonal flows on warm Martian slopes|warm seasonal flows]] observed on some slopes, and [[Martian geyser|geysers]] fed by spring thawing of carbon dioxide (CO<sub>2</sub>) ice near Mars' poles.<ref name="drift" />

On October 19, 2014, NASA reported that the ''Mars Odyssey'' Orbiter,<ref name="NASA-20141019-ODY">{{cite web |last1=Webster |first1=Guy |last2=Brown |first2=Dwayne |title=NASA's Mars Odyssey Orbiter Watches Comet Fly Near |url=http://www.jpl.nasa.gov/news/news.php?feature=4346 |date=October 19, 2014 |work=[[NASA]] |access-date=October 20, 2014 }}</ref> as well as the ''[[Mars Reconnaissance Orbiter]]''<ref name="NASA-20141019-MRO">{{cite web |last1=Webster |first1=Guy |last2=Brown |first2=Dwayne |title=NASA's Mars Reconnaissance Orbiter Studies Comet Flyby |url=http://www.jpl.nasa.gov/news/news.php?feature=4344 |date=October 19, 2014 |work=[[NASA]] |access-date=October 20, 2014 }}</ref> and ''[[MAVEN]]'',<ref name="NASA-20141019-MAV">{{cite web |last1=Jones |first1=Nancy |last2=Steigerwald |first2=Bill |last3=Webster |first3=Guy |last4=Brown |first4=Dwayne |title=NASA's MAVEN Studies Passing Comet and Its Effects |url=http://www.jpl.nasa.gov/news/news.php?feature=4345 |date=October 19, 2014 |work=[[NASA]] |access-date=October 20, 2014 }}</ref> were healthy after the [[C/2013 A1|Comet Siding Spring]] flyby.<ref name="NASA-20141019">{{cite web |last1=Webster |first1=Guy |last2=Brown |first2=Dwayne |last3=Jones |first3=Nancy |last4=Steigerwald |first4=Bill |title=All Three NASA Mars Orbiters Healthy After Comet Flyby |url=http://www.jpl.nasa.gov/news/news.php?feature=4347 |date=October 19, 2014 |work=[[NASA]] |access-date=October 20, 2014 }}</ref><ref name="NYT-20141019">{{cite news |agency=Agence France-Presse |title=A Comet's Brush With Mars |url=https://www.nytimes.com/2014/10/19/science/a-comets-brush-with-mars.html |date=October 19, 2014 |work=[[The New York Times]] |access-date=October 20, 2014 }}</ref>

In 2010, a spokesman for NASA's Jet Propulsion Laboratory stated that ''Odyssey'' could continue operating until at least 2016.<ref name="ut-81675">{{cite web | url=http://www.universetoday.com/81675/the-longest-martian-odyssey-ever | title=The Longest Martian Odyssey Ever | work=Universe Today | date=December 13, 2010 | first=Ken | last=Kremer | archive-url=https://web.archive.org/web/20101220000650/http://www.universetoday.com/81675/the-longest-martian-odyssey-ever/ | archive-date=December 20, 2010 | url-status=live }}</ref> This estimate has since been extended to the end of 2025.<ref name="jpl-20230315" />

<gallery widths="200px" heights="155px">
File:Animation of 2001 Mars Odyssey trajectory around Sun.gif|Animation of ''2001 Mars Odyssey''{{'}}s trajectory around Sun<br/>{{legend2|magenta|''2001 Mars Odyssey''}}{{·}}{{legend2|RoyalBlue|Earth}}{{·}}{{legend2|Lime|Mars}}
File:Animation of 2001 Mars Odyssey trajectory around Mars.gif|Animation of ''2001 Mars Odyssey''{{'s}} trajectory around [[Mars]] from October 24, 2001, to October 24, 2002<br />{{legend2|magenta| ''2001 Mars Odyssey''}}{{·}}{{legend2| Lime|[[Mars]]}}
Image:Mgs  odyssey.gif|''Mars Odyssey'' as imaged by ''[[Mars Global Surveyor]]''
Image:Mars Radiation Environment Experiment.jpg|MARIE hardware, designed to measure radiation
</gallery>

=== Major discoveries ===
{{further|Water on Mars}}

By 2008, ''Mars Odyssey'' had mapped the basic distribution of water below the shallow surface.<ref>{{cite web|url=http://grs.lpl.arizona.edu/latestresults.jsp|title=January, 2008: Hydrogen Map|publisher=Lunar & Planetary Lab at The University of Arizona|access-date=2015-06-30 |archive-date=2008-10-13 |archive-url=https://web.archive.org/web/20081013115534/http://grs.lpl.arizona.edu/latestresults.jsp|url-status=dead}}</ref> The ground truth for its measurements came on July 31, 2008, when NASA announced that the [[Phoenix lander]] confirmed the presence of water on Mars,<ref name="nasa-20080620">{{cite web | url=http://www.nasa.gov/mission_pages/phoenix/news/phoenix-20080620.html | title=Confirmation of Water on Mars | work=Phoenix Mars Lander | date=June 20, 2008 | publisher=NASA | archive-url=https://web.archive.org/web/20080701104400/http://www.nasa.gov/mission_pages/phoenix/news/phoenix-20080620.html | archive-date=July 1, 2008 | url-status=live }}</ref> as predicted in 2002 based on data from the ''Odyssey'' orbiter. The science team is trying to determine whether the water ice ever thaws enough to be available for microscopic life, and if carbon-containing chemicals and other raw materials for life are present.<ref>{{Cite news |title=NASA's Phoenix touches, tastes Martian water |work=The Economic Times |url=https://economictimes.indiatimes.com/nasas-phoenix-touches-tastes-martian-water/articleshow/3313142.cms?from=mdr |access-date=2022-06-24}}</ref>

The orbiter also discovered vast deposits of bulk water ice near the surface of equatorial regions.<ref name='Jack Wilson'/> Evidence for equatorial hydration is both morphological and compositional and is seen at both the [[Medusae Fossae]] formation and the [[Tharsis Montes]].<ref name='Jack Wilson'/>

[[File:PIA26203-Mars-HorizonViews-OdysseyTHEMIS-20230509.webm|thumb|center|600px|<div align="center">Mars—horizon views (video; 1:24; Odyssey orbiter; [[Thermal Emission Imaging System|THEMIS camera]]; 9 May 2023)</div>]]