View source for Astronomy:Mars Reconnaissance Orbiter

{{Short description|NASA spacecraft active since 2005}}
{{Italic title}}
{{Infobox spaceflight
| name               = ''Mars Reconnaissance Orbiter''
| image              = Mars Reconnaissance Orbiter, front view, artist's concept (PIA07245).jpg
| image_caption      = ''Mars Reconnaissance Orbiter'' spacecraft
| mission_type       = [[Astronomy:Mars|Mars]] orbiter
| operator           = [[Organization:NASA|NASA]]{{\}}[[Organization:Jet Propulsion Laboratory|Jet Propulsion Laboratory]]
| website            = {{URL|https://mars.nasa.gov/mro/}}<br />{{URL|nasa.gov/mission_pages/MRO/main/index.html}}
| COSPAR_ID          = 2005-029A
| SATCAT             = 28788
| mission_duration   = <small>{{Age in years, months and days|year=2005|month=08|day=12}} from launch ({{Age in years, months and days|year=2006|month=03|day=10}} ({{age in sols|2006|03|10}}&nbsp;[[Astronomy:Timekeeping on Mars#Sols|sols]]) at Mars)</small>
| spacecraft_type    = 
| manufacturer       = [[Company:Lockheed Martin Space Systems|Lockheed Martin]]{{\}}[[Organization:University of Arizona|University of Arizona]]{{\}}[[Organization:Applied Physics Laboratory|Applied Physics Laboratory]]{{\}}[[Organization:Italian Space Agency|Italian Space Agency]]{{\}}[[Company:Malin Space Science Systems|Malin Space Science Systems]]
| launch_mass        = {{convert|2180|kg|abbr=on}}<ref>{{cite web |url=https://solarsystem.nasa.gov/missions/mars-reconnaissance-orbiter/in-depth/ |title=Mars Reconnaissance Orbiter |publisher=NASA's Solar System Exploration website |access-date=December 1, 2022 |archive-date=September 8, 2018 |archive-url=https://web.archive.org/web/20180908033328/https://solarsystem.nasa.gov/missions/mars-reconnaissance-orbiter/in-depth/ |url-status=live }}</ref>
| dry_mass           = {{convert|1031|kg|abbr=on}}
| payload_mass       = {{convert|139|kg|abbr=on}}
| power              = 600–2000&nbsp;[[Watt|watt]]s
| launch_date        = {{start-date|August 12, 2005, 11:43:00|timezone=yes}}&nbsp;UTC
| launch_rocket      = [[Engineering:Atlas V|Atlas V]] 401
| launch_site        = {{wipe|Cape Canaveral Air Force Station}} SLC-41
| launch_contractor  = [[Company:Lockheed Martin Space|Lockheed Martin]]
| last_contact       = <!-- {{end-date|[date]}} -->
| decay_date         = 
| orbit_epoch        = 
| orbit_reference    = [[Astronomy:Areocentric orbit|Areocentric]]
| orbit_regime       = [[Astronomy:Sun-synchronous orbit|Sun-synchronous]]<ref name="Lyons"/>
| orbit_periapsis    = 
| orbit_apoapsis     = 
| orbit_inclination  = 93&nbsp;degrees<ref name="Lyons"/>
| orbit_period       = 111 minutes
| apsis              = areion
| interplanetary     = {{Infobox spaceflight/IP
 | type                = orbiter
 | object              = [[Astronomy:Mars|Mars]]
 | orbits              = 
 | arrival_date        = March 10, 2006, 21:24:00&nbsp;UTC<br /><small>[[Astronomy:Timekeeping on Mars|MSD]] 46990 12:48 AMT</small>
 }}
| insignia           = Mars Reconnaissance Orbiter insignia.png
| insignia_alt       = Mars Reconnaissance Orbiter insignia
| insignia_caption   = Official insignia of the ''Mars Reconnaissance Orbiter'' mission
| insignia_size      = 90px
}}

The '''''Mars Reconnaissance Orbiter''''' ('''''MRO''''') is a [[Engineering:Spacecraft|spacecraft]] designed to search for the existence of [[Astronomy:Water on Mars|water on Mars]] and provide support for missions to [[Astronomy:Mars|Mars]], as part of [[Organization:NASA|NASA]]'s [[Astronomy:Mars Exploration Program|Mars Exploration Program]]. It was launched from Cape Canaveral on August 12, 2005, at 11:43 UTC and reached Mars on March 10, 2006, at 21:24 UTC. In November 2006, after six months of [[Astronomy:Aerobraking|aerobraking]], it entered its final science [[Physics:Orbit|orbit]] and began its primary science phase.

Mission objectives include observing the [[Astronomy:Climate of Mars|climate of Mars]], investigating [[Astronomy:Geology of Mars|geologic forces]], providing [[Engineering:Spatial reconnaissance|reconnaissance]] of future landing sites, and relaying data from surface missions back to Earth. To support these objectives, the ''MRO'' carries different scientific instruments, including three cameras, two [[Physics:Spectrometer|spectrometer]]s and a [[Astronomy:SHARAD|subsurface radar]]. As of July 29, 2023, the ''MRO'' has returned over 450 terabits of data, helped choose safe landing sites for NASA's Mars [[Astronomy:List of Mars landers|landers]], discovered pure water ice in new craters and further evidence that water once flowed on the surface on Mars.<ref name=":5">{{Cite web |title=Mars Reconnaissance Orbiter |url=https://mars.nasa.gov/mro/ |url-status=live |archive-url=https://web.archive.org/web/20230729210615/https://mars.nasa.gov/mro/ |archive-date=July 29, 2023 |access-date=July 29, 2023 |website=[[Organization:NASA|NASA]]}}</ref>

The spacecraft continues to operate at Mars, far beyond its intended design life. Due to its critical role as a high-speed data-relay for ground missions, NASA intends to continue the mission as long as possible, at least through the late 2020s. As of {{Currentmonth}} {{Currentday}}, {{Currentyear}}, the ''MRO'' has been active at Mars for {{Age in sols|day1=10|year1=2006|month1=March}} [[Astronomy:Mars sol|sols]], or {{Age in years, months and days|2006|March|10}}, and is the third longest-lived spacecraft to orbit Mars, after ''[[Astronomy:2001 Mars Odyssey|2001 Mars Odyssey]]'' and ''[[Astronomy:Mars Express|Mars Express]]''.

== Pre-launch ==
After the failures of the ''[[Astronomy:Mars Climate Orbiter|Mars Climate Orbiter]]'' and the [[Astronomy:Mars Polar Lander|Mars Polar Lander]] missions in 1999, [[Organization:NASA|NASA]] reorganized and replanned its [[Astronomy:Mars Exploration Program|Mars Exploration Program]]. In October 2000, NASA announced its reformulated Mars plans, which reduced the number of planned missions and introduced a new theme, "follow the water". The plans included the ''Mars Reconnaissance Orbiter'' (''MRO''), to be launched in 2005.<ref name="NASA Unveils Plans for 21st Century Mars Campaign"/>

On October 3, 2001, NASA chose [[Company:Lockheed Martin|Lockheed Martin]] as the primary contractor for the spacecraft's fabrication.<ref name="NASA Picks Lockheed Martin to Build 2005 Mars Craft"/> By the end of 2001 all of the mission's instruments were selected. There were no major setbacks during the ''MRO''<nowiki/>'s construction, and the spacecraft was shipped to John F. Kennedy Space Center on May 1, 2005, to prepare it for launch.<ref name="Moving Day For Mars Reconnaissance Orbiter"/>

== Mission objectives ==
[[File:Components of Mars Reconnaissance Orbiter.png|thumb|upright=2.1|Components of ''MRO'']]
''MRO'' has both scientific and "mission support" objectives. The prime science mission was initially designed to last from November 2006 to November 2008, and the mission support phase from November 2006 to November 2010. Both missions have been extended.<ref>{{Cite web |title=428154main_Planetary_Science.pdf |url=https://www.nasa.gov/pdf/428154main_Planetary_Science.pdf |access-date=July 29, 2023 |website=[[Organization:NASA|NASA]] |page=47 |archive-date=May 10, 2017 |archive-url=https://web.archive.org/web/20170510075252/https://www.nasa.gov/pdf/428154main_Planetary_Science.pdf |url-status=live }}</ref>

The formal science objectives of ''MRO'' are to observe the present climate, particularly its atmospheric circulation and seasonal variations; search for signs of water, both past and present, and understand how it altered the planet's surface; map and characterize the geological forces that shaped the surface.<ref name="mro-science-paper">{{cite journal |last1=Zurek |first1=Richard W. |last2=Smrekar |first2=Suzanne E. |title=An overview of the Mars Reconnaissance Orbiter (MRO) science mission |journal=Journal of Geophysical Research: Planets |date=2007 |volume=112 |issue=E5 |pages=E05S01 |doi=10.1029/2006JE002701 |bibcode=2007JGRE..112.5S01Z |language=en |issn=2156-2202|doi-access=free }}</ref>

To support other missions to Mars, the ''MRO'' also has mission support objectives. They are to provide data relay services from ground missions back to Earth, and characterize the safety and feasibility of potential future landing sites and [[Astronomy:Mars rover|Mars rover]] traverses.<ref name="mro-science-paper" />

''MRO'' played a key role in choosing safe landing sites for the [[Engineering:Phoenix (spacecraft)|''Phoenix'']] lander in 2008, ''[[Organization:Mars Science Laboratory|Mars Science Laboratory]]'' / ''[[Engineering:Curiosity (rover)|Curiosity]]'' rover in 2012, ''[[Astronomy:InSight|InSight]]'' lander in 2018, and the ''[[Astronomy:Mars 2020|Mars 2020]]'' / [[Engineering:Perseverance (rover)|''Perseverance'']] rover in 2021.<ref>{{Cite web |last=Sharrow |first=R. |date=2006-07-24 |title=pds-geosciences.wustl.edu/missions/mro/docs/mro_mission.txt |url=https://pds-geosciences.wustl.edu/missions/mro/docs/mro_mission.txt |access-date=July 29, 2023 |website=pds-geosciences.wustl.edu |archive-date=December 27, 2021 |archive-url=https://web.archive.org/web/20211227134240/https://pds-geosciences.wustl.edu/missions/mro/docs/mro_mission.txt |url-status=live }}</ref><ref>{{Cite web |last=Greicius |first=Tony |date=2018-05-02 |title=NASA Evaluates Four Candidate Sites for 2016 Mars Mission |url=http://www.nasa.gov/mission_pages/insight/news/insight20130904.html |access-date=2023-07-29 |website=NASA |archive-date=February 28, 2014 |archive-url=https://web.archive.org/web/20140228154241/http://www.nasa.gov/mission_pages/insight/news/insight20130904.html |url-status=live }}</ref><ref>{{Cite journal |last1=Grant |first1=John A. |last2=Golombek |first2=Matthew P. |last3=Wilson |first3=Sharon A. |last4=Farley |first4=Kenneth A. |last5=Williford |first5=Ken H. |last6=Chen |first6=Al |date=2018-12-01 |title=The science process for selecting the landing site for the 2020 Mars rover |url=https://www.sciencedirect.com/science/article/pii/S0032063318301077 |journal=Planetary and Space Science |language=en |volume=164 |pages=106–126 |doi=10.1016/j.pss.2018.07.001 |bibcode=2018P&SS..164..106G |s2cid=125118346 |issn=0032-0633 |access-date=July 29, 2023 |archive-date=August 4, 2023 |archive-url=https://web.archive.org/web/20230804022054/https://www.sciencedirect.com/science/article/abs/pii/S0032063318301077 |url-status=live }}</ref>

== Launch and orbital insertion ==
{{Multiple image|total_width = 350
| image1            = MRO Liftoff.jpeg
| caption1          = Launch of [[Engineering:Atlas V|Atlas V]] carrying the ''MRO'', 11:43:00 UTC August 12, 2005
| image2            = MRO Transfer Orbit 2.png
| caption2          = Transfer orbit from Earth to Mars. TCM-1 to TCM-4 denote the planned [[Astronomy:Orbital maneuver|trajectory correction maneuvers]].
| image3            = Animation of Mars Reconnaissance Orbiter trajectory around Mars.gif
| caption3          = Animation of ''MRO''{{'}}s trajectory around [[Astronomy:Mars|Mars]] from March 10, 2006, to September 30, 2007<br />{{legend2|magenta| ''MRO''}}{{·}}{{legend2| Lime|[[Astronomy:Mars|Mars]]}}
| image4            = MRO Aerobrake.jpg
| caption4          = Artwork of ''MRO'' aerobraking
| direction         = horizontal
| perrow            = 2 / 2
}}

On August 12, 2005, ''MRO'' was launched aboard an [[Engineering:Atlas V|Atlas V-401]] rocket from Space Launch Complex 41 at {{wipe|Cape Canaveral Air Force Station}}.<ref name="ILS To Launch Mars Reconnaissance Orbiter For NASA On Atlas V"/> The [[Engineering:Centaur (rocket stage)|Centaur upper stage]] of the rocket completed its burns over a 56-minute [[Astronomy:Orbital period|period]] and placed ''MRO'' into an [[Astronomy:Hohmann transfer orbit|interplanetary transfer orbit]] towards Mars.<ref name="NASA's Multipurpose Mars Mission Successfully Launched"/>

''MRO'' cruised through interplanetary space for seven and a half months before reaching Mars. While en route, most of the scientific instruments and experiments were tested and [[Calibration|calibrated]]. To ensure proper orbital insertion upon reaching Mars, four [[Physics:Trajectory|trajectory]] [[Astronomy:Orbital maneuver|correction maneuvers]] were planned and a fifth emergency maneuver was discussed.<ref>{{Cite web |title=Approach: Trajectory Correction Maneuvers 4, 5, & 6 – NASA |url=https://mars.nasa.gov/mro/mission/timeline/mtapproach/approachtcms/ |access-date=2023-08-18 |website=mars.nasa.gov |language=en}}</ref> However, only three trajectory correction maneuvers were necessary, which saved {{Convert|27|kg}} of fuel that would be usable during ''MRO''<nowiki/>'s extended mission.<ref name="U.S. Spacecraft Enters Orbit Around Mars"/>

''MRO'' began orbital insertion by approaching Mars on March 10, 2006, and passing above its southern hemisphere at an altitude of {{Convert|370|-|400|km|sp=us|abbr=off}}. All six of ''MRO''<nowiki/>'s main engines burned for 27 minutes to slow the probe by {{Convert|1000|m/s|sp=us}}. The burn was remarkably accurate, as the insertion route had been designed more than three months prior, with the achieved [[Astronomy:Delta-v|change in speed]] only 0.01% short from the design, necessitating an additional 35 second burn time.<ref>{{cite web |title=Mars Reconnaissance Orbiter Interplanetary Cruise Navigation |url=https://issfd.org/ISSFD_2007/3-4.pdf |url-status=live |archive-url=https://web.archive.org/web/20220530170237/https://issfd.org/ISSFD_2007/3-4.pdf |archive-date=May 30, 2022 |access-date=21 August 2022 |page=16}}</ref>

Completion of the orbital insertion placed the orbiter in a highly [[Astronomy:Elliptic orbit|elliptical]] polar orbit with a period of approximately 35.5 hours.<ref name="New Mars Orbiter Ready for Action"/> Shortly after insertion, the periapsis – the point in the orbit closest to Mars – was {{Convert|426|km|abbr=on}} from the surface<ref name="New Mars Orbiter Ready for Action"/> ({{Convert|3806|km|abbr=on}} from the planet's center). The apoapsis – the point in the orbit farthest from Mars – was {{Convert|44500|km|abbr=on}} from the surface ({{Convert|47972|km|abbr=on}} from the planet's center).<ref>{{cite journal |last1=Zurek |first1=Richard W. |last2=Smrekar |first2=Suzanne E. |title=An overview of the Mars Reconnaissance Orbiter (MRO) science mission |journal=Journal of Geophysical Research: Planets |date=2007 |volume=112 |issue=E5 |page=15|doi=10.1029/2006JE002701 |bibcode=2007JGRE..112.5S01Z |language=en |issn=2156-2202|doi-access=free }}</ref>

When ''MRO'' entered orbit, it joined five other active spacecraft that were either in orbit or on the planet's surface: ''[[Astronomy:Mars Global Surveyor|Mars Global Surveyor]]'', ''[[Astronomy:Mars Express|Mars Express]]'', ''[[Astronomy:2001 Mars Odyssey|2001 Mars Odyssey]]'', and the two [[Astronomy:Mars Exploration Rover|Mars Exploration Rover]]s (''[[Engineering:Spirit (rover)|Spirit]]'' and ''[[Engineering:Opportunity (rover)|Opportunity]]''). This set a new record for the most operational spacecraft in the immediate vicinity of Mars.<ref>{{Cite web |title=Every mission to Mars ever |url=https://www.planetary.org/space-missions/every-mars-mission |access-date=2023-08-22 |website=[[Organization:The Planetary Society|The Planetary Society]] |language=en}}</ref>

On March 30, 2006, ''MRO'' began the process of [[Astronomy:Aerobraking|aerobraking]], a three-step procedure that halved the fuel needed to achieve a lower, more circular orbit with a shorter period. First, during its first five orbits of the planet (one Earth week), ''MRO'' used its [[Engineering:Thrusters (spacecraft)|thrusters]] to drop the periapsis of its orbit into aerobraking altitude. Second, while using its thrusters to make minor corrections to its periapsis altitude, ''MRO'' maintained aerobraking altitude for 445 planetary orbits (about five Earth months) to reduce the apoapsis of the orbit to {{convert|450|km|sp=us}}. This was done in such a way so as to not heat the spacecraft too much, but also dip enough into the atmosphere to slow the spacecraft down. Third, after the process was complete, ''MRO'' used its thrusters to move its periapsis out of the edge of the atmosphere on August 30, 2006.<ref name="aero"/><ref name="Mars Orbiter Successfully Makes Big Burn"/><ref>{{Cite web |title=NASA – NASA Mars Reconnaissance Orbiter Reaches Planned Flight Path |url=https://www.nasa.gov/mission_pages/MRO/news/mro-20060912.html |access-date=2023-08-18 |website=www.nasa.gov |language=en}}</ref>

In September 2006, ''MRO'' fired its thrusters twice more to adjust its final, nearly circular orbit to approximately {{Convert|250|to|316|km|abbr=on}} above the surface, with a period of about 112 minutes.<ref name="Mars Reconnaissance Orbiter Reaches Planned Flight Path"/><ref name="Fact Sheet: HiRISE"/> The [[Astronomy:SHARAD|SHARAD radar]] antennas were deployed on September 16. All of the scientific instruments were tested and most were turned off prior to the [[Astronomy:Solar conjunction|solar conjunction]] that occurred from October 7 to November 6, 2006. This was done to prevent charged particles from the Sun from interfering with signals and potentially endangering the spacecraft.<ref>{{Cite web |title=Solar Conjunction {{!}} Mars in our Night Sky |url=https://mars.nasa.gov/all-about-mars/night-sky/solar-conjunction |access-date=2023-08-18 |website=NASA Mars Exploration |language=en}}</ref> After the conjunction ended the "primary science phase" began.<ref name=":4">{{Cite journal |last1=Zurek |first1=Richard W. |last2=Smrekar |first2=Suzanne E. |date=2007-05-12 |title=An overview of the Mars Reconnaissance Orbiter (MRO) science mission |journal=Journal of Geophysical Research |language=en |volume=112 |issue=E5 |pages=E05S01 |doi=10.1029/2006JE002701 |bibcode=2007JGRE..112.5S01Z |issn=0148-0227|doi-access=free }}</ref>

== Timeline ==
[[File:169384main pia09189-330.jpg|thumb|Tectonic fractures within the [[Astronomy:Candor Chasma|Candor Chasma]] region of Valles Marineris, Mars, retain ridge-like shapes as the surrounding bedrock erodes away.|267x267px]][[File:MRO sees Curiosity landing.jpg|thumb|The ''Curiosity'' rover during atmospheric entry as seen by HiRISE on August 6, 2012. Supersonic parachute and backshell visible]]
[[File:PIA19913-MarsLandingSite-Ares3Mission-TheMartian-2015Film-20150517.jpg|thumb|Image taken by HiRISE of [[Astronomy:Acidalia Planitia|Acidalia Planitia]] on May 17, 2015, where the novel ''The Martian'' and its film adaptation take place]]
[[File:PIA22487-Mars-BeforeAfterDust-20180719.gif|thumb|Comparison of Mars with and without the [[Astronomy:Dust storms on Mars|dust storm]] that caused the end of the ''Opportunity'' rover, taken by MARCI in 2018]]{{Main|Timeline of Mars Reconnaissance Orbiter}}
On September 29, 2006 ([[Astronomy:Timekeeping on Mars#Sols|sol]] {{age in sols|2005|08|12|2006|09|29}}), ''MRO'' took its first [[Image resolution|high resolution image]] from its science orbit. This image is said to resolve items as small as 90&nbsp;cm (3&nbsp;feet) in diameter. On October 6, NASA released detailed pictures from the ''MRO'' of Victoria crater along with the ''Opportunity'' rover on the rim above it.<ref name="bbc" /> In November, problems began to surface in the operation of two ''MRO'' spacecraft instruments. A [[Stepping (debugging)|stepping]] mechanism in the Mars Climate Sounder (MCS) skipped on multiple occasions resulting in a [[Physics:Field of view|field of view]] that was slightly out of position. By December, normal operations of the instrument had been suspended, although a [[Mitigation|mitigation]] strategy allows the instrument to continue making most of its intended observations.<ref name="planetary" /> Also, an increase in [[Physics:Noise (spectral phenomenon)|noise]] and resulting bad pixels has been observed in several [[Engineering:Charge-coupled device|CCD]]s of the High Resolution Imaging Science Experiment (HiRISE). Operation of this camera with a longer warm-up time{{Efn|Due to the coldness of space, spacecraft instruments need to be "warmed up" to operate properly.<ref>{{Cite web |title=Thermal Systems – NASA |url=https://mars.nasa.gov/mro/mission/spacecraft/parts/thermal/ |access-date=2023-08-21 |website=mars.nasa.gov |language=en}}</ref>}} has alleviated the issue. However, the cause is still unknown and may return.<ref name="newscientist" />

On November 17, 2006, NASA announced the successful test of the ''MRO'' as an orbital communications relay. Using the NASA rover ''Spirit'' as the point of origin for the transmission, the ''MRO'' acted as a relay for transmitting data back to Earth.<ref>{{Cite web |date=November 17, 2006 |title=NASA's Newest Mars Orbiter Passes Communications Relay Test |url=https://mars.nasa.gov/news/336/nasas-newest-mars-orbiter-passes-communications-relay-test/ |url-status=live |archive-url=https://web.archive.org/web/20230120181523/https://mars.nasa.gov/news/336/nasas-newest-mars-orbiter-passes-communications-relay-test/ |archive-date=January 20, 2023 |access-date=January 20, 2023 |website=NASA Mars Exploration Program}}</ref> HiRISE was able to photograph the ''Phoenix'' lander during its [[Engineering:Parachute|parachuted]] [[Astronomy:Mars landing|descent]] to [[Astronomy:Vastitas Borealis|Vastitas Borealis]] on May 25, 2008 (sol {{age in sols|2005|08|12|2008|05|25}}).<ref>{{Cite web |date=May 27, 2008 |title=PIA10705: Phoenix Descending with Crater in the Background |url=https://photojournal.jpl.nasa.gov/catalog/PIA10705 |access-date=January 20, 2023 |website=NASA JPL Photojournal |archive-date=August 7, 2022 |archive-url=https://web.archive.org/web/20220807215107/https://photojournal.jpl.nasa.gov/catalog/PIA10705 |url-status=live }}</ref>

The orbiter continued to experience recurring problems in 2009, including four spontaneous resets, culminating in a four-month shut-down of the spacecraft from August to December.<ref name="AW"/> While engineers have not determined the cause of the recurrent resets, they have created new software to help troubleshoot the problem should it recur. Another spontaneous reset occurred in September 2010.<ref name=":2">{{Cite web |title=In Depth {{!}} Mars Reconnaissance Orbiter |url=https://solarsystem.nasa.gov/missions/mars-reconnaissance-orbiter/in-depth |access-date=2023-02-21 |website=NASA Solar System Exploration |archive-date=April 3, 2020 |archive-url=https://web.archive.org/web/20200403194812/https://solarsystem.nasa.gov/missions/mars-reconnaissance-orbiter/in-depth/ |url-status=live }}</ref>

On March 3, 2010, the ''MRO'' passed another significant milestone, having transmitted over 100 terabits of data back to Earth, which was more than all other interplanetary probes sent from Earth combined.<ref name="Scientists wowed by data from Mars probe">{{cite web|url=http://www.nbcnews.com/id/35698998/ns/technology_and_science-space/t/scientists-wowed-data-mars-probe|title=Scientists Wowed by Data From Mars Probe|website=NBC News|date=March 4, 2010 |access-date=April 21, 2013|archive-date=April 14, 2013|archive-url=https://web.archive.org/web/20130414205728/http://www.nbcnews.com/id/35698998/ns/technology_and_science-space/t/scientists-wowed-data-mars-probe/|url-status=live}}</ref>

In December 2010, the first Extended Mission began. Goals included exploring [[Astronomy:Climate of Mars#Seasons|seasonal processes]], searching for surface changes, and providing support for other Martian spacecraft. This lasted until October 2012, after which NASA started the ''MRO''<nowiki/>'s second Extended Mission, which lasted until October 2014.<ref name=":2" /> As of 2023, the ''MRO'' has completed five missions, and is currently on its sixth.<ref>{{Cite web |date=April 25, 2022 |title=NASA Extends Exploration for 8 Planetary Science Missions |url=https://mars.nasa.gov/news/9175/nasa-extends-exploration-for-8-planetary-science-missions/ |access-date=July 7, 2023 |website=NASA Mars Exploration |archive-date=July 8, 2023 |archive-url=https://web.archive.org/web/20230708025149/https://mars.nasa.gov/news/9175/nasa-extends-exploration-for-8-planetary-science-missions/ |url-status=live }}</ref>

On August 6, 2012 (sol {{age in sols|2005|08|12|2012|08|06}}), the orbiter passed over Gale crater, the landing site of the Mars Science Laboratory mission, during its [[Astronomy:Atmospheric entry|EDL]] phase. It captured an image via the HiRISE camera of the ''Curiosity'' rover descending with its backshell and [[Supersonic speed|supersonic]] parachute.<ref>{{Cite web |date=August 6, 2012 |title=Curiosity Spotted on Parachute by Orbiter |url=https://mars.nasa.gov/resources/4242/curiosity-spotted-on-parachute-by-orbiter/?site=msl |access-date=January 20, 2023 |website=NASA MARS Exploration Program |archive-date=December 1, 2022 |archive-url=https://web.archive.org/web/20221201214008/https://mars.nasa.gov/resources/4242/curiosity-spotted-on-parachute-by-orbiter/?site=msl |url-status=live }}</ref> In December 2014 and April 2015, ''Curiosity'' was photographed again by HiRISE inside Gale Crater.<ref name="mro-in-depth">{{cite web |title=Mars Reconnaissance Orbiter – In Depth |url=https://solarsystem.nasa.gov/missions/mars-reconnaissance-orbiter/in-depth/ |url-status=live |archive-url=https://web.archive.org/web/20180908033328/https://solarsystem.nasa.gov/missions/mars-reconnaissance-orbiter/in-depth/ |archive-date=September 8, 2018 |access-date=April 24, 2020 |website=NASA Solar System Exploration}}</ref>

Another computer anomaly occurred on March 9, 2014, when the ''MRO'' put itself into [[Engineering:Safe mode in spacecraft|safe mode]] after an unscheduled swap from one computer to another. The ''MRO'' resumed normal science operations four days later. This occurred again in April 11, 2015, after which the MRO returned to full operational capabilities a week later.<ref name=":2" />

NASA reported that the ''MRO'',<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=[[Organization:NASA|NASA]] |access-date=October 20, 2014 |archive-date=June 9, 2017 |archive-url=https://web.archive.org/web/20170609192135/https://www.jpl.nasa.gov/news/news.php?feature=4344 |url-status=live }}</ref> as well as 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=[[Organization:NASA|NASA]] |access-date=October 20, 2014 |archive-date=May 8, 2017 |archive-url=https://web.archive.org/web/20170508024228/https://www.jpl.nasa.gov/news/news.php?feature=4346 |url-status=live }}</ref> and ''MAVEN'' orbiter<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=[[Organization:NASA|NASA]] |access-date=October 20, 2014 |archive-date=July 4, 2017 |archive-url=https://web.archive.org/web/20170704193211/https://www.jpl.nasa.gov/news/news.php?feature=4345 |url-status=live }}</ref> had a chance to study the Comet Siding Spring flyby on October 19, 2014.<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=[[Organization:NASA|NASA]] |access-date=October 20, 2014 |archive-date=July 3, 2017 |archive-url=https://web.archive.org/web/20170703011007/https://www.jpl.nasa.gov/news/news.php?feature=4347 |url-status=live }}</ref><ref name="NYT-20141019">{{cite news |date=October 19, 2014 |title=A Comet's Brush With Mars |work={{wipe|New York Times}} |agency=Agence France-Presse |url=https://www.nytimes.com/2014/10/19/science/a-comets-brush-with-mars.html |url-status=live |url-access=subscription |access-date=October 20, 2014 |archive-url=https://web.archive.org/web/20141027234401/http://www.nytimes.com/2014/10/19/science/a-comets-brush-with-mars.html |archive-date=October 27, 2014}}</ref> To minimize risk of damage from the material shed by the comet, the ''MRO'' made orbital adjustments on July 2, 2014 and August 27, 2014. During the flyby, the ''MRO'' took the best ever pictures of a comet from the [[Astronomy:Oort cloud|Oort cloud]] and was not damaged.<ref name="mro-in-depth" />

In January 2015, the ''MRO'' discovered and identified the wreckage of Britain's ''[[Astronomy:Beagle 2|Beagle 2]]'', which was lost during its landing phase in 2003 and was thought to have crashed. The images revealed that ''Beagle 2'' had actually landed safely, but one or two of its [[Physics:Solar panels on spacecraft|solar panels]] had failed to fully deploy, which blocked the radio antenna.<ref name="mro-in-depth" /><ref>{{Cite news |last=Davis |first=Nicola |date=2016-11-11 |title=Beagle 2 Mars probe was 'excruciatingly close' to success, new research reveals |language=en-GB |work=The Guardian |url=https://www.theguardian.com/science/2016/nov/11/beagle-2-mars-probe-was-excruciatingly-close-to-success-new-research-reveals |access-date=2023-03-07 |issn=0261-3077 |archive-date=March 7, 2023 |archive-url=https://web.archive.org/web/20230307164136/https://www.theguardian.com/science/2016/nov/11/beagle-2-mars-probe-was-excruciatingly-close-to-success-new-research-reveals |url-status=live }}</ref> In October 2016, the crash site of another lost spacecraft, [[Engineering:Schiaparelli EDM|''Schiaparelli'' EDM]], was photographed by the ''MRO'', using both the CTX and HiRISE cameras.<ref name="mro-in-depth" />

On July 29, 2015, the ''MRO'' was placed into a new orbit to provide communications support during the anticipated arrival of the ''InSight'' Mars lander mission in September 2016.<ref>{{Cite web|date=2015-07-30|title=Mars orbiter prepares for next year's InSight lander arrival
|first=David |last=Szondy
|url=https://newatlas.com/mars-orbiter-prepares-for-new-arrival/38665/|access-date=2023-01-21|website=New Atlas|archive-url=https://web.archive.org/web/20150730210411/http://www.gizmag.com/mars-orbiter-prepares-for-new-arrival/38665/ |archive-date=July 30, 2015}}</ref> The maneuver's engine burn lasted for 75 seconds.<ref>{{Cite web |url=http://www.nasa.gov/jpl/mro/nasa-mars-orbiter-preparing-for-mars-landers-2016-arrival |title=NASA Mars Orbiter Preparing for Mars Lander's 2016 Arrival |date=July 28, 2015 |access-date=July 30, 2015 |archive-date=July 30, 2015 |archive-url=https://web.archive.org/web/20150730234714/http://www.nasa.gov/jpl/mro/nasa-mars-orbiter-preparing-for-mars-landers-2016-arrival/ |url-status=live }}</ref> ''InSight'' was delayed and missed the 2016 [[Engineering:Launch window|launch window]], but was successfully launched during the next window on May 5, 2018, and landed on November 26, 2018.<ref>{{Cite news|url=https://mars.nasa.gov/news/8392/nasa-insight-lander-arrives-on-martian-surface/|title=NASA InSight lander arrives on Martian surface|work=NASA's Mars Exploration Program|access-date=November 26, 2018|language=en|archive-date=August 6, 2019|archive-url=https://web.archive.org/web/20190806152832/https://mars.nasa.gov/news/8392/nasa-insight-lander-arrives-on-martian-surface/|url-status=live}}</ref>

Due to the longevity of the mission, a number of ''MRO'' components have started deteriorating. From the start of the mission in 2005 to 2017, the ''MRO'' had used a [[Engineering:Miniature inertial measurement unit|Miniature inertial measurement unit (MIMU)]] for altitude and orientation control. After 58,000 hours of use, and limited signs of life, the orbiter switched over to a backup, which, as of 2018, has reached 52,000 hours of use. To conserve the life of the backup, NASA switched from MIMUs to an "all-stellar" mode for routine operations in 2018. The "all-stellar" mode uses [[Astronomy:Star tracker|cameras]] and [[Pattern recognition|pattern recognition]] software to determine the location of stars, which can then be used to identify the ''MRO''<nowiki/>'s orientation.<ref name=":6">{{cite news |date=February 9, 2018 |title=Mars Reconnaissance Orbiter Preparing for Years Ahead |work=NASA/JPL |publisher=JPL Press Office |url=https://www.jpl.nasa.gov/news/news.php?feature=7059 |url-status=live |access-date=April 24, 2020 |archive-url=https://web.archive.org/web/20200803181743/https://www.jpl.nasa.gov/news/news.php?feature=7059 |archive-date=August 3, 2020}}</ref> Problems with blurring in pictures from HiRISE and battery degradation also arose in 2017 but have since been resolved.<ref>{{Cite web |last=McEwen |first=Alfred |date=April 23, 2019 |title=HiRISE Team Overcomes Imaging Glitches as Mars Reconnaissance Orbiter Eyes another Decade in Orbit |url=https://www.planetary.org/articles/hirise-imaging-glitches |access-date=2023-08-04 |website=[[Organization:The Planetary Society|The Planetary Society]] |language=en |archive-date=February 5, 2023 |archive-url=https://web.archive.org/web/20230205005547/https://www.planetary.org/articles/hirise-imaging-glitches |url-status=live }}</ref> In August 2023, electronic units within the HiRISE's CCD RED4 sensor began to fail as well, and are causing visual artifacts in pictures taken.<ref>{{Cite web |title=HiRISE {{!}} Image Catalog |url=https://www.uahirise.org/catalog/ |access-date=2023-10-31 |website=www.uahirise.org}}</ref>

In 2017, the [[Physics:Cryocooler|cryocoolers]] used by CRISM completed their lifecycle, limiting the instrument's capabilities to [[Physics:Visible spectrum|visible wavelengths]], instead of its full wavelength range. In 2022, NASA announced the shutdown of CRISM in its entirety, and the instrument was formally retired on April 3, 2023, after creating two final, near global, maps using prior data and a more limited second spectrometer that did not require cryocoolers.<ref name="mro-in-depth" /><ref name=":3" /><ref>{{Cite web |last=Hartono |first=Naomi |date=2023-04-25 |title=NASA Retires Mineral Mapping Instrument on Mars Orbiter |url=http://www.nasa.gov/feature/jpl/nasa-retires-mineral-mapping-instrument-on-mars-orbiter |access-date=2023-06-23 |website=NASA |archive-date=June 22, 2023 |archive-url=https://web.archive.org/web/20230622075122/https://www.nasa.gov/feature/jpl/nasa-retires-mineral-mapping-instrument-on-mars-orbiter/ |url-status=live }}</ref>

== Instruments ==
{{multiple image
| align             = right
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| total_width       = 440
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| footer            = 
| image1            = Mars Reconnaissance Orbiter HiRISE.jpg
| alt1              = aaa
| caption1          = High Resolution Imaging Science Experiment (HiRISE)
| image4            = CTX (Context Camera).jpg
| alt4              = bbb
| caption4          = Context Camera (CTX)
| image3            = Mars Climate Orbiter - mco marci.jpg
| alt3              = bbb
| caption3          = Mars Color Imager (MARCI)
| image2            = MRO CRISM prelaunch 2.jpg
| alt2              = bbb
| caption2          = CRISM
| image5            = Climate Sounder Instrument for Mars Reconnaissance Orbiter PIA13352.jpg
| alt5              = bbb
| caption5          = Mars Climate Sounder (MCS)
}}

Three cameras, two spectrometers and a radar are included on the orbiter along with three engineering instruments and two "science-facility experiments", which use data from engineering subsystems to collect science data. Two of the engineering instruments are being used to test and demonstrate new equipment for future missions.<ref name="Spacecraft Parts: Instruments"/> The ''MRO'' takes around 29,000 images per year.<ref>{{Cite web |title=Mars Reconnaissance Orbiter By the Numbers |url=https://mars.nasa.gov/resources/7741/mars-reconnaissance-orbiter-by-the-numbers |access-date=2023-08-18 |website=NASA Mars Exploration |language=en}}</ref>

=== HiRISE ===

The High Resolution Imaging Science Experiment (HiRISE) camera is a {{convert|0.5|m|abbr=on}} [[Astronomy:Reflecting telescope|reflecting telescope]], the largest ever carried on a [[Astronomy:Outer space|deep space]] mission, and has a [[Angular resolution|resolution]] of 1&nbsp;microradian, or {{convert|0.3|m|abbr=on}} from an altitude of {{convert|300|km|abbr=on}}. In comparison, [[Astronomy:Satellite imagery|satellite images of Earth]] are generally available with a resolution of {{convert|0.5|m|abbr=on}}.<ref>{{Cite web |last=Jagula |first=Dexter |date=February 19, 2022 |title=SATELLITE IMAGERY FOR EVERYONE |url=https://spectrum.ieee.org/commercial-satellite-imagery |access-date=July 6, 2023 |website=IEEE Spectrum |archive-date=July 7, 2023 |archive-url=https://web.archive.org/web/20230707162153/https://spectrum.ieee.org/commercial-satellite-imagery |url-status=live }}</ref> HiRISE collects images in three color bands, 400 to 600&nbsp;nm (blue–green or B–G), 550 to 850&nbsp;nm (red) and 800 to 1,000&nbsp;nm (near infrared).<ref name="MRO HiRISE Camera Specifications"/>

Red color images are 20,264 [[Pixel|pixel]]s across ({{convert|6|km|abbr=on}} wide), and B–G and NIR are 4,048 pixels across ({{convert|1.2|km|abbr=on}} wide). HiRISE's onboard computer reads these lines in time with the orbiter's [[Physics:Ground speed|ground speed]], and images are potentially unlimited in length. Practically however, their length is limited by the computer's 28 [[Gigabit|Gb]] memory capacity, and the nominal maximum size is 20,000&nbsp;×&nbsp;40,000 pixels (800 megapixels) and 4,000&nbsp;×&nbsp;40,000 pixels (160 megapixels) for B–G and NIR images. Each 16.4&nbsp;Gb image is compressed to 5&nbsp;Gb before transmission and release to the general public on the HiRISE website in [[JPEG 2000]] format.<ref name="Fact Sheet: HiRISE"/><ref name="HiRISE: Instrument Development"/> To facilitate the mapping of potential landing sites, HiRISE can produce [[Earth:Photogrammetry|stereo pairs]] of images from which topography can be calculated to an accuracy of {{convert|0.25|m|abbr=on}}.<ref name="HiRISE"/> HiRISE was built by Ball Aerospace & Technologies Corp.<ref>{{Cite web |date=October 16, 2019 |title=HiRISE Views NASA's InSight and Curiosity on Mars |url=https://mars.nasa.gov/news/8528/hirise-views-nasas-insight-and-curiosity-on-mars |access-date=2023-07-29 |website=NASA Mars Exploration |language=en |archive-date=July 29, 2023 |archive-url=https://web.archive.org/web/20230729222312/https://mars.nasa.gov/news/8528/hirise-views-nasas-insight-and-curiosity-on-mars/ |url-status=live }}</ref>

=== CTX ===<!-- Other articles link here. -->
The '''Context Camera (CTX)''' provides [[Grayscale|grayscale]] images (500 to 800&nbsp;nm) with a pixel resolution up to about {{convert|6|m|abbr=on}}. CTX is designed to provide context maps for the targeted observations of HiRISE and CRISM, and is also used to mosaic large areas of Mars, monitor a number of locations for changes over time, and to acquire stereo (3D) coverage of key regions and potential future landing sites.<ref name="Context Camera Investigation on board the Mars Reconnaissance Orbiter"/><ref name="Present-day activity, monitoring, and documentation of gullies with the Mars Reconnaissance Orbiter (MRO) Context Camera (CTX)"/> The optics of CTX consist of a {{convert|350|mm|abbr=on}} [[Focal length|focal length]] <!-- diameter unknown -->[[Astronomy:Maksutov telescope#Maksutov–Cassegrains|Maksutov Cassegrain telescope]] with a 5,064 pixel wide line array CCD. The instrument takes pictures {{convert|30|km|abbr=on}} wide and has enough internal memory to store an image {{convert|160|km|abbr=on}} long before loading it into the [[Astronomy:Mars Reconnaissance Orbiter#Electronic systems|main computer]].<ref name="MRO Context Imager (CTX) Instrument Description"/> The camera was built, and is operated by [[Company:Malin Space Science Systems|Malin Space Science Systems]]. CTX had mapped more than 99% of Mars by March 2017 and helped create an interactive map of Mars in 2023.<ref>{{Cite web |title=A Decade of Compiling the Sharpest Mars Map |url=https://mars.nasa.gov/resources/8333/a-decade-of-compiling-the-sharpest-mars-map |access-date=2023-08-04 |website=NASA Mars Exploration |language=en |archive-date=June 8, 2023 |archive-url=https://web.archive.org/web/20230608001551/https://mars.nasa.gov/resources/8333/a-decade-of-compiling-the-sharpest-mars-map/ |url-status=live }}</ref><ref>{{Cite web |last=Greicius |first=Tony |date=2023-04-04 |title=New Interactive Mosaic Uses NASA Imagery to Show Mars in Vivid Detail |url=http://www.nasa.gov/feature/jpl/new-interactive-mosaic-uses-nasa-imagery-to-show-mars-in-vivid-detail |access-date=2023-08-04 |website=NASA |archive-date=May 19, 2023 |archive-url=https://web.archive.org/web/20230519065931/http://www.nasa.gov/feature/jpl/new-interactive-mosaic-uses-nasa-imagery-to-show-mars-in-vivid-detail/ |url-status=live }}</ref>

=== MARCI ===
{{Main|Astronomy:Mars Color Imager}}

The '''Mars Color Imager (MARCI)''' is a wide-angle, relatively low-resolution camera that views the surface of Mars in five [[Physics:Visible light|visible]] and two [[Physics:Ultraviolet|ultraviolet]] bands. Each day, MARCI collects about 84 images and produces a global map with pixel resolutions of {{convert|1|to|10|km|abbr=on}}. This map provides a weekly weather report for Mars, helps to characterize its seasonal and annual variations, and maps the presence of water vapor and ozone in its atmosphere.<ref name="Spacecraft Parts: Instruments: MARCI"/> The camera was built and is operated by Malin Space Science Systems. It has a 180-degree [[Engineering:Fisheye lens|fisheye lens]] with the seven color filters bonded directly on a single CCD sensor.<ref name="msss2"/><ref name="marci">{{cite web |title=NASA – NSSDCA – Experiment – Details |url=https://nssdc.gsfc.nasa.gov/nmc/experiment/display.action?id=1998-073A-01 |website=nssdc.gsfc.nasa.gov |access-date=2 February 2023 |archive-date=April 14, 2020 |archive-url=https://web.archive.org/web/20200414205438/https://nssdc.gsfc.nasa.gov/nmc/experiment/display.action?id=1998-073A-01 |url-status=live }} {{PD-notice}}</ref> The same MARCI camera was onboard [[Astronomy:Mars Climate Orbiter|Mars Climate Orbiter]] launched in 1998.<ref>{{cite web |title=MARS RECONNAISSANCE ORBITER (MRO) MARS COLOR IMAGER (MARCI) INSTRUMENT DESCRIPTION |url=https://www.msss.com/science/mro-marci-instrument-description.php |website=msss.com |publisher=Malin Space Science Systems |access-date=2 February 2023 |archive-date=February 2, 2023 |archive-url=https://web.archive.org/web/20230202131846/https://www.msss.com/science/mro-marci-instrument-description.php |url-status=live }}</ref>

=== CRISM ===

The '''Compact Reconnaissance Imaging Spectrometer for Mars (CRISM)''' instrument is a [[Physics:VNIR|visible and near infrared]] [[Physics:Spectrometer|spectrometer]] that is used to produce detailed maps of the surface [[Earth:Mineralogy|mineralogy]] of Mars.<ref name="CRISM Instrument Overview"/> It operates from 362 to 3920&nbsp;nm, measures the [[Physics:Electromagnetic spectrum|spectrum]] in 544&nbsp;[[Channel (digital image)|channels]] (each 6.55&nbsp;nm wide), and has a resolution of {{convert|18|m|abbr=on}} at an altitude of {{convert|300|km|abbr=on}}.<ref name="CRISM Instrument Overview"/><ref>{{Cite web |title=CRISM |url=https://mars.nasa.gov/mro/mission/instruments/crism/ |access-date=January 20, 2023 |website=NASA MARS Reconnaissance Orbiter |archive-date=November 12, 2022 |archive-url=https://web.archive.org/web/20221112191737/https://mars.nasa.gov/mro/mission/instruments/crism/ |url-status=live }}</ref> CRISM is being used to identify minerals and chemicals indicative of the past or present existence of water on the surface of Mars. These materials include [[Chemistry:Iron oxide|iron oxide]]s, phyllosilicates, and carbonates, which have characteristic patterns in their visible-infrared energy.<ref>{{Cite journal |last1=Murchie |first1=Scott L. |last2=Mustard |first2=John F. |last3=Ehlmann |first3=Bethany L. |last4=Milliken |first4=Ralph E. |last5=Bishop |first5=Janice L. |last6=McKeown |first6=Nancy K. |last7=Noe Dobrea |first7=Eldar Z. |last8=Seelos |first8=Frank P. |last9=Buczkowski |first9=Debra L. |last10=Wiseman |first10=Sandra M. |last11=Arvidson |first11=Raymond E. |last12=Wray |first12=James J. |last13=Swayze |first13=Gregg |last14=Clark |first14=Roger N. |last15=Des Marais |first15=David J. |date=2009-09-22 |title=A synthesis of Martian aqueous mineralogy after 1 Mars year of observations from the Mars Reconnaissance Orbiter |journal=Journal of Geophysical Research |language=en |volume=114 |issue=E2 |pages=E00D06 |doi=10.1029/2009JE003342 |bibcode=2009JGRE..114.0D06M |issn=0148-0227|doi-access=free }}</ref> The CRISM instrument was shut down on April 3, 2023.<ref name=":3">{{Cite web | url=https://www.nasa.gov/feature/nasa-extends-exploration-for-8-planetary-science-missions | title=NASA Extends Exploration for 8 Planetary Science Missions | date=April 25, 2022 | access-date=April 26, 2022 | archive-date=April 26, 2022 | archive-url=https://web.archive.org/web/20220426215212/https://www.nasa.gov/feature/nasa-extends-exploration-for-8-planetary-science-missions/ | url-status=live }}</ref>

=== MCS ===
<!-- could add anchor Mars Climate Sounder (so redirect can find) -->

The '''Mars Climate Sounder (MCS)''' looks both down and horizontally through the atmosphere in order to quantify the [[Astronomy:Atmosphere of Mars#Vertical structure|atmosphere's vertical variations]]. It is a spectrometer with one visible/near infrared channel (0.3 to 3.0&nbsp;μm) and eight [[Physics:Far infrared|far infrared]] (12 to 50&nbsp;μm) channels selected for the purpose. MCS observes the atmosphere on the horizon of Mars (as viewed from MRO) by breaking it up into vertical slices and taking measurements within each slice in {{convert|5|km|abbr=on}} increments. These measurements are assembled into daily global weather maps to show the basic variables of [[Astronomy:Climate of Mars|Martian weather]]: temperature, pressure, humidity, and [[Astronomy:Martian soil#Atmospheric dust|dust density]].<ref name="Spacecraft Parts: Instruments: MCS"/>

This instrument, supplied by NASA's [[Organization:Jet Propulsion Laboratory|Jet Propulsion Laboratory]] (JPL), is an updated version of a heavier, larger instrument originally developed at JPL for the 1992 ''[[Astronomy:Mars Observer|Mars Observer]]'' and 1998 ''[[Astronomy:Mars Climate Orbiter|Mars Climate Orbiter]]'' missions,<ref>{{Cite web |title=MRO MCS |url=https://arcnav.psi.edu/urn:nasa:pds:context:instrument:mcs.mro |access-date=January 20, 2023 |website=Planetary Data System |archive-date=January 20, 2023 |archive-url=https://web.archive.org/web/20230120181600/https://arcnav.psi.edu/urn:nasa:pds:context:instrument:mcs.mro |url-status=live }}</ref> which both failed.

=== SHARAD ===
{{Main|Astronomy:SHARAD}}
[[File:MRO using SHARAD.jpg|thumb|An artist's concept of ''MRO'' using SHARAD to "look" under the surface of Mars]]
The '''Shallow Radar (SHARAD)''' sounder experiment onboard ''MRO'' is designed to probe the internal structure of the Martian polar [[Earth:Ice cap|ice cap]]s. It also gathers planet-wide information about underground layers of regolith, [[Earth:Rock (geology)|rock]], and [[Earth:Ice|ice]] that might be accessible from the surface. SHARAD emits [[Physics:High frequency|HF]] radio waves between 15 and 25&nbsp;[[Megahertz|MHz]], a range that allows it to resolve layers as thin as {{convert|7|m|abbr=on}} to a maximum depth of {{convert|3|km|3|abbr=on}}. It has a horizontal resolution of {{convert|0.3|to|3|km|1|abbr=on}}.<ref name="nasa"/> SHARAD is designed to complement the Mars Express [[Astronomy:MARSIS|MARSIS]] instrument, which has coarser resolution but penetrates to a much greater depth. Both SHARAD and MARSIS were made by the [[Organization:Italian Space Agency|Italian Space Agency]].<ref>{{cite web |title=SHARAD |url=https://mars.nasa.gov/mro/mission/instruments/sharad/ |website=mars.nasa.gov |publisher=NASA |access-date=April 24, 2020 |language=en |archive-date=March 18, 2020 |archive-url=https://web.archive.org/web/20200318003102/https://mars.nasa.gov/mro/mission/instruments/sharad/ |url-status=live }}</ref>

=== Engineering instruments and experiments ===
In addition to its imaging equipment, ''MRO'' carries three engineering instruments.  The [[Engineering:Electra (radio)|Electra]] communications package is a [[Physics:Ultra high frequency|UHF]] [[Software-defined radio|software-defined radio]] that provides a flexible platform for evolving relay capabilities.<ref name="Electra">{{cite web |title=The Electra Proximity Link Payload for Mars Relay Telecommunications and Navigation |author1=Charles D. Edwards Jr. |author2=Thomas C. Jedrey |author3=Eric Schwartzbaum |author4=and Ann S. Devereaux |author5=Ramon DePaula |author6=Mark Dapore |author7=Thomas W. Fischer |url=http://trs-new.jpl.nasa.gov/dspace/bitstream/2014/7832/1/03-2150.pdf  |archive-url=https://web.archive.org/web/20130502170707/http://trs-new.jpl.nasa.gov/dspace/bitstream/2014/7832/1/03-2150.pdf |archive-date=May 2, 2013 }}</ref> It is designed to communicate with other spacecraft as they approach, land, and operate on Mars. In addition to protocol controlled inter-spacecraft data links of 1&nbsp;kbit/s to 2&nbsp;Mbit/s, Electra also provides Doppler data collection, open loop recording and a highly accurate timing service based on an ultra-stable oscillator.<ref name=":1">{{Cite web |date=March 2006 |title=Mars Reconnaissance Orbiter Arrival Press Kit |url=https://mars.nasa.gov/files/mro/mro-arrival.pdf |access-date=January 20, 2023 |website=NASA |archive-date=December 10, 2022 |archive-url=https://web.archive.org/web/20221210105536/https://mars.nasa.gov/files/mro/mro-arrival.pdf |url-status=live }}</ref><ref>{{Cite web |last1=Taylor |first1=Jim |last2=Lee |first2=Dennis K. |last3=Shambayati |first3=Shervin |date=September 2006 |title=Mars Reconnaissance Orbiter Telecommunications |url=https://descanso.jpl.nasa.gov/DPSummary/MRO_092106.pdf |access-date=January 20, 2023 |website=JPL DESCANSO |archive-date=January 20, 2023 |archive-url=https://web.archive.org/web/20230120201350/https://descanso.jpl.nasa.gov/DPSummary/MRO_092106.pdf |url-status=live }}</ref> [[Physics:Doppler effect|Doppler information]] for approaching vehicles can be used for final descent targeting or descent and landing trajectory recreation. Doppler information on landed vehicles allows scientists to accurately determine the surface location of Mars landers and rovers. The two Mars Exploration Rover (MER) spacecraft utilized an earlier generation UHF relay radio providing similar functions through the Mars Odyssey orbiter. The Electra radio has relayed information to and from the MER spacecraft, ''Phoenix'' lander and ''Curiosity'' rover.<ref>{{Cite web |title=Electra |url=https://mars.nasa.gov/mro/mission/instruments/electra/ |access-date=January 20, 2023 |website=NASA MARS Reconnaissance Orbiter |archive-date=September 28, 2022 |archive-url=https://web.archive.org/web/20220928104722/https://mars.nasa.gov/mro/mission/instruments/electra/ |url-status=live }}</ref> 

[[File:Phobos by MRO.jpg|thumb|An image of Phobos taken by HiRISE on March 23, 2008 from a distance of around {{convert|6,800|km}}<ref>{{Cite web |date=2008-04-09 |title=PIA10368: Phobos from 6,800 Kilometers (Color) |url=https://photojournal.jpl.nasa.gov/catalog/PIA10368 |url-status=live |archive-url=https://web.archive.org/web/20230723221437/https://photojournal.jpl.nasa.gov/catalog/PIA10368 |archive-date=July 23, 2023 |access-date=July 16, 2023 |website=photojournal.jpl.nasa.gov}}</ref>]]
During the cruise phase, the ''MRO'' also used the {{Ka band}} Telecommunications Experiment Package to demonstrate a less power-intensive way to communicate with Earth.<ref>{{Cite web |title=Ka-band – NASA |url=https://mars.nasa.gov/mro/mission/instruments/kaband/ |access-date=2023-08-21 |website=mars.nasa.gov |language=en}}</ref>

The Optical Navigation Camera images the Martian moons, [[Astronomy:Phobos (moon)|Phobos]] and [[Astronomy:Deimos (moon)|Deimos]], against background stars to precisely determine ''MRO''<nowiki/>'s orbit. Although this is not critical, it was included as a technology test for future orbiting and landing of spacecraft.<ref name="Spacecraft Parts: Optical Navigation Camera" /> The Optical Navigation Camera was tested successfully in February and March 2006.<ref name="Optical Navigation Demonstration Near Mars Multimedia Feature" />

Two additional science investigations are also on the spacecraft. The Gravity Field Investigation Package measures variations in the [[Physics:Gravity of Mars|Martian gravitational field]] through variations in the spacecraft's speed. Speed changes are detected by measuring doppler shifts in ''MRO''<nowiki/>'s radio signals received on Earth. Data from this investigation can be used to understand the subsurface geology of Mars, determine the density of the atmosphere and track seasonal changes in the location of carbon dioxide deposited on the surface.<ref name="Spacecraft Parts: Gravity Field Investigation Package" />

The Atmospheric Structure Investigation used sensitive onboard [[Physics:Accelerometer|accelerometer]]s to deduce the ''in situ'' atmospheric density of Mars during aerobraking. The measurements helped provide greater understanding of seasonal wind variations, the effects of dust storms, and the structure of the atmosphere.<ref>{{Cite web |title=Accelerometers – NASA |url=https://mars.nasa.gov/mro/mission/instruments/atmosaccel/ |access-date=2023-08-18 |website=mars.nasa.gov |language=en}}</ref>

== Spacecraft Systems ==
[[File:Mars orbiters.jpg|thumb|Size comparison of ''MRO'' with predecessors]]

=== Structure ===
Workers at [[Company:Lockheed Martin Space Systems|Lockheed Martin Space Systems]] in Denver assembled the spacecraft structure and attached the instruments. Instruments were constructed at the Jet Propulsion Laboratory, the [[Organization:University of Arizona|University of Arizona]] [[Organization:Lunar and Planetary Laboratory|Lunar and Planetary Laboratory]] in Tucson, Arizona, [[Organization:Johns Hopkins University|Johns Hopkins University]] [[Organization:Applied Physics Laboratory|Applied Physics Laboratory]] in Laurel, Maryland, the Italian Space Agency in Rome, and Malin Space Science Systems in San Diego.<ref name="Rad 750"/>

The structure is made mostly of carbon composites and aluminum-honeycombed plates. The [[Chemistry:Titanium|titanium]] fuel tank takes up most of the volume and mass of the spacecraft and provides most of its [[Engineering:Structural engineering|structural integrity]].<ref>{{Cite web |title=Spacecraft Parts: Structures |url=http://marsprogram.jpl.nasa.gov/mro/mission/sc_structures.html  |archive-url=https://web.archive.org/web/20060301180710/http://marsprogram.jpl.nasa.gov/mro/mission/sc_structures.html |archive-date=March 1, 2006 |access-date=January 20, 2023 |website=NASA Jet Propulsion Laboratory}}</ref> The spacecraft's total mass is less than {{convert|2180|kg|abbr=on}} with an unfueled [[Mass ratio|dry mass]] less than {{convert|1031|kg|abbr=on}}.<ref name="Spacecraft Summary"/>

=== Power systems ===
[[File:Mars Reconnaissance Orbiter solar panel.jpg|thumb|The ''MRO'' solar panel]]
''MRO'' gets all of its electrical power from two solar panels, each of which can move independently around two axes (up-down, or left-right rotation). Each solar panel measures {{convert|5.35|×|2.53|m|abbr=on}} and has {{convert|9.5|m2|abbr=on}}<!-- The area does not match the dimensions because the dimensions are not 100% filled with solar cells, as seen on the picture to the right. --> covered with 3,744 individual photovoltaic cells.<ref name=ps/><ref name=":1" /> Its high-efficiency solar cells are able to convert more than 26% of the energy it receives from the [[Astronomy:Sun|Sun]] directly into electricity and are connected together to produce a total output of 32&nbsp;volts. Whilst orbiting Mars, the panels together produce 600–2000{{Efn|Various figures are given for the power, ranging from 600 W to 2000 W at the aphelion to 1000 W at an unspecified location in the MRO's orbit. Due to the conflicting information from reliable sources, a range has been used, instead of an exact number.<ref name="auto">{{Cite web |title=Electrical Power |url=https://mars.nasa.gov/mro/mission/spacecraft/parts/electricalpower/ |access-date=January 31, 2023 |website=NASA MRO |archive-date=December 6, 2022 |archive-url=https://web.archive.org/web/20221206092503/https://mars.nasa.gov/mro/mission/spacecraft/parts/electricalpower/ |url-status=live }}</ref><ref name=":1" /><ref name="mro-science-paper" />}} watts of power;<ref name="auto"/><ref name=":1" /><ref name="mro-science-paper" /> in contrast, the panels would generate 6,000 watts in a comparable Earth orbit by being closer to the Sun.<ref name="ps"/><ref name=":1" />

''MRO'' has two rechargeable [[Physics:Nickel–hydrogen battery|nickel-hydrogen batteries]] used to power the spacecraft when it is not facing the Sun. Each battery has an energy storage capacity of 50&nbsp;[[Ampere hour|ampere hour]]s (180&nbsp;[[Coulomb|kC]]). The full range of the batteries cannot be used due to voltage constraints on the spacecraft, but allows the operators to extend the battery life—a valuable capability, given that battery drain is one of the most common causes of long-term satellite failure. Planners anticipate that only 40% of the batteries' capacities will be required during the lifetime of the spacecraft.<ref name=ps/>

=== Electronic systems ===
''MRO''<nowiki/>'s main computer is a 133&nbsp;MHz, 10.4&nbsp;million [[Engineering:Transistor|transistor]], 32-bit, [[Astronomy:RAD750|RAD750]] processor, a [[Engineering:Radiation hardening|radiation-hardened]] version of a [[PowerPC]] 750 or G3 processor with a purpose-built [[Engineering:Motherboard|motherboard]].<ref name="Rad 7503"/> The operating system software is [[Software:VxWorks|VxWorks]] and has extensive fault protection protocols and monitoring.<ref name="mes"/>

Data is stored in a 160&nbsp;Gbit (20&nbsp;GB) [[Flash memory|flash memory]] module consisting of over 700 memory chips, each with a 256&nbsp;[[Megabit|Mbit]] capacity. This memory capacity is not actually that large considering the amount of data to be acquired; for example, a single image from the HiRISE camera can be as large as 28&nbsp;Gb.<ref name=mes/>

=== Telecommunications system ===
[[File:Mars Reconnaissance Orbiter HGA installation.jpg|thumb|''MRO'' High Gain Antenna installation]][[File:MarsReconnaissanceOrbiter-Views-EarthMoon-20220422.jpg|thumb|''MRO'' views Earth and the Moon (April 22, 2022).]]
When it was launched, the Telecom Subsystem on ''MRO'' was the best digital communication system sent into deep space, and for the first time used capacity-approaching turbo-codes. It was more powerful than any previous [[Astronomy:Deep space exploration|deep space mission]], and is able to transmit data more than ten times faster than previous Mars missions.<ref name=":7">{{Cite web |last1=Taylor |first1=Jim |last2=Lee |first2=Dennis K. |last3=Shambayati |first3=Shervin |date=September 2006 |title=Mars Reconnaissance Orbiter Telecommunications |url=https://descanso.jpl.nasa.gov/DPSummary/MRO_092106.pdf |access-date=August 20, 2023 |website=[[Organization:JPL|JPL]]}}</ref> Along with the Electra communications package, the system consists of a very large ({{convert|3|m|abbr=on}}) antenna, which is used to transmit data through the Deep Space Network via [[Astronomy:X-band|X-band]] frequencies at 8.41&nbsp;[[Gigahertz|GHz]]. It also demonstrates the use of the K<sub>a</sub> band at 32&nbsp;GHz for higher data rates.<ref name=":0">{{Cite book |last1=Shambayati |first1=S. |last2=Davarian |first2=F. |last3=Morabito |first3=D. |title=2005 IEEE Aerospace Conference |chapter=Link design and planning for Mars Reconnaissance Orbiter (MRO) Ka-band (32 GHZ) telecom demonstration |date=March 12, 2005 |chapter-url=https://ieeexplore.ieee.org/document/1559447 |publisher=IEEE |pages=1559–1569 |doi=10.1109/AERO.2005.1559447 |isbn=0-7803-8870-4 |s2cid=20667200 |access-date=January 31, 2023 |archive-date=June 13, 2018 |archive-url=https://web.archive.org/web/20180613083533/https://ieeexplore.ieee.org/document/1559447/ |url-status=live }}</ref> Maximum transmission speed from Mars can be as high as 6&nbsp;Mbit/s, but averages between 0.5 and 4&nbsp;Mbit/s.<ref name=":7" /> The spacecraft carries two 100-watt X-band Travelling Wave Tube Amplifiers (TWTA) (one of which is a backup), one 35-watt K<sub>a</sub>-band [[Engineering:Amplifier|amplifier]], and two [[Astronomy:Small Deep Space Transponder|Small Deep Space Transponder]]s (SDSTs).<ref name=ant/><ref>{{Cite journal |last1=Shambayati |first1=Shervin |last2=Morabito |first2=David |last3=Border |first3=James S. |last4=Davarian |first4=Faramaz |last5=Lee |first5=Dennis |last6=Mendoza |first6=Ricardo |last7=Britcliffe |first7=Michael |last8=Weinreb |first8=Sander |date=January 1, 2006 |title=Mars Reconnaissance Orbiter Ka-Band (32 GHz) Demonstration: Cruise Phase Operations |url=https://citeseerx.ist.psu.edu/document?repid=rep1&type=pdf&doi=11d500fe17602ad9e20093dcdedd067faa22b7f8 |journal=SpaceOps 2006 Conference |doi=10.2514/6.2006-5786 |isbn=978-1-62410-051-2 |via=ResearchGate |access-date=January 31, 2023 |archive-date=January 31, 2023 |archive-url=https://web.archive.org/web/20230131210441/https://citeseerx.ist.psu.edu/document?repid=rep1&type=pdf&doi=11d500fe17602ad9e20093dcdedd067faa22b7f8 |url-status=live }}</ref>

Two smaller low-gain antennas are also present for lower-rate communication during emergencies and special events. These antennas do not have focusing dishes and can transmit and receive from any direction. They are an important backup system to ensure that ''MRO'' can always be reached, even if its main antenna is pointed away from the Earth.<ref>{{cite web |title=Antennas – NASA |url=https://mars.nasa.gov/mro/mission/spacecraft/parts/antennas/ |website=mars.nasa.gov |access-date=1 February 2023 |language=en |archive-date=January 20, 2023 |archive-url=https://web.archive.org/web/20230120201347/https://mars.nasa.gov/mro/mission/spacecraft/parts/antennas/ |url-status=live }}</ref><ref>{{cite web |title=Mars Reconnaissance Orbiter Spacecraft |url=https://pds-geosciences.wustl.edu/missions/mro/docs/mro_insthost.txt |website=pds-geosciences.wustl.edu |access-date=1 February 2023 |archive-date=July 23, 2023 |archive-url=https://web.archive.org/web/20230723204041/https://pds-geosciences.wustl.edu/missions/mro/docs/mro_insthost.txt |url-status=live }}</ref>

The K<sub>a</sub> band subsystem was used to show how such a system could be used by spacecraft in the future. Due to lack of spectrum at 8.41&nbsp;GHz X-band, future high-rate deep space missions will use 32&nbsp;GHz K<sub>a</sub>-band. NASA Deep Space Network (DSN) implemented K<sub>a</sub>-band receiving capabilities at all three of its complexes (Goldstone, Canberra and Madrid) over its 34-m beam-waveguide (BWG) antenna subnet.<ref name=":0" /> K<sub>a</sub>-band tests were also planned during the science phase, but during aerobraking a switch failed, limiting the X-band high gain antenna to a single amplifier.<ref name="MRO Waveguide Transfer Switch Anomaly"/> If this amplifier fails all high-speed X-band communications will be lost. The K<sub>a</sub> downlink is the only remaining backup for this functionality, and since the K<sub>a</sub>-band capability of one of the SDST transponders has already failed,<ref name="CSAM Augments X-Ray Inspection of Die Attach (MRO Ka-Band Anomaly)"/> (and the other might have the same problem) JPL decided to halt all K<sub>a</sub>-band demonstrations and hold the remaining capability in reserve.<ref name="In-Flight Anomalies and Lessons Learned from the Mars Reconnaissance Orbiter Mission"/>

By November 2013, the ''MRO'' had passed 200 terabits in the amount of science data returned. The data returned by the mission is more than three times the total data returned via NASA's Deep Space Network for all the other missions managed by NASA's Jet Propulsion Laboratory over the past 10 years.<ref>{{cite news | title = Prolific NASA Mars Orbiter Passes Big Data Milestone | date = November 8, 2013 | url = http://www.jpl.nasa.gov/news/news.php?release=2013-324&1 | work = Jet Propulsion Laboratory – NASA | access-date = November 9, 2013 | archive-date = August 9, 2020 | archive-url = https://web.archive.org/web/20200809141751/https://www.jpl.nasa.gov/news/news.php?release=2013-324&1 | url-status = live }}</ref>[[File:Victoria crater from HiRise.jpg|thumb|High-resolution image of [[Astronomy:Victoria (crater)|Victoria crater]] from HiRISE on October 3, 2006. The rover ''Opportunity'' can be seen at roughly the "ten o'clock" position along the rim of the crater.]]

=== Propulsion and attitude control ===
The spacecraft uses a {{convert|1175|L|abbr=on}} fuel tank filled with {{convert|1187|kg|abbr=on}} of [[Chemistry:Hydrazine|hydrazine]] [[Chemistry:Monopropellant|monopropellant]]. Fuel pressure is regulated by adding pressurized helium gas from an external tank. Seventy percent of the propellant was used for orbital insertion,<ref name="spp"/> and it has enough propellant to keep functioning into the 2030s.<ref>{{cite news |last=Clark |first=Stephen |url=http://astronomynow.com/2015/08/20/nasa-to-rely-on-mars-programmes-silent-workhorse-for-years-to-come/ |title=NASA to rely on Mars programme's silent workhorse for years to come |work=Astronomy Now |date=August 20, 2015 |access-date=August 20, 2015 |archive-date=August 22, 2015 |archive-url=https://web.archive.org/web/20150822185400/http://astronomynow.com/2015/08/20/nasa-to-rely-on-mars-programmes-silent-workhorse-for-years-to-come/ |url-status=live }}</ref>

''MRO'' has 20 rocket engine thrusters on board. Six large thrusters each produce {{convert|170|N|abbr=on}} of thrust for a total of {{convert|1020|N|abbr=on}} meant mainly for orbital insertion. These thrusters were originally designed for the [[Astronomy:Mars Surveyor 2001 Lander|Mars Surveyor 2001 Lander]]. Six medium thrusters each produce {{convert|22|N|abbr=on}} of thrust for trajectory correction maneuvers and [[Astronomy:Spacecraft attitude control|attitude control]] during orbit insertion. Finally, eight small thrusters each produce {{convert|0.9|N|abbr=on}} of thrust for attitude control during normal operations.<ref name=spp/>

Four [[Engineering:Reaction wheel|reaction wheel]]s are also used for precise attitude control during activities requiring a highly stable platform, such as high-resolution imaging, in which even small motions can cause blurring of the image. Each wheel is used for one axis of motion. The fourth wheel is a backup in case one of the other three wheels fails. Each wheel weighs {{convert|10|kg|abbr=on}} and can be spun as fast as 100&nbsp;Hz or 6,000&nbsp;[[Revolutions per minute|rpm]].<ref name=spp/><ref>{{Cite web |title=Control Devices |url=https://mars.nasa.gov/mro/mission/spacecraft/parts/gnc/controldevices/ |access-date=January 31, 2023 |website=NASA MRO |archive-date=January 31, 2023 |archive-url=https://web.archive.org/web/20230131210911/https://mars.nasa.gov/mro/mission/spacecraft/parts/gnc/controldevices/ |url-status=live }}</ref>

In order to determine the spacecraft's orbit and facilitate maneuvers, 16 Sun sensors – eight primaries and eight backups – are placed around the spacecraft to calibrate solar direction relative to the orbiter's frame. Two star trackers, [[Engineering:Digital camera|digital camera]]s used to map the position of catalogued [[Astronomy:Star|star]]s, provide NASA with full, three-axis knowledge of the spacecraft orientation and attitude. A primary and backup Miniature Inertial Measurement Unit (MIMU), provided by [[Company:Honeywell|Honeywell]], measures changes to the spacecraft attitude as well as any non-gravitationally induced changes to its linear velocity. Each MIMU is a combination of three accelerometers and three ring-laser [[Engineering:Gyroscope|gyroscope]]s. These systems are all critically important to ''MRO'', as it must be able to point its camera to a very high precision in order to take the high-quality pictures that the mission requires. It has also been specifically designed to minimize any vibrations on the spacecraft, so as to allow its instruments to take images without any distortions caused by vibrations.<ref name="Spacecraft Parts: Guidance, Navigation, and Control Systems"/><ref>{{Cite web |title=Sensors |url=https://mars.nasa.gov/mro/mission/spacecraft/parts/gnc/sensors/ |access-date=January 20, 2023 |website=NASA Mars Reconnaissance Orbiter |archive-date=January 20, 2023 |archive-url=https://web.archive.org/web/20230120201344/https://mars.nasa.gov/mro/mission/spacecraft/parts/gnc/sensors/ |url-status=live }}</ref><ref>{{cite web | title=Mars Reconnaissance Orbiter Design Approach for High-Resolution Surface Imaging | work=PDF | publisher=American Astronautical Society | url=http://trs-new.jpl.nasa.gov/dspace/bitstream/2014/37230/1/03-0246.pdf | access-date=2023-07-29  | archive-url=https://web.archive.org/web/20090227062102/http://trs-new.jpl.nasa.gov/dspace/bitstream/2014/37230/1/03-0246.pdf | archive-date=2009-02-27 }}</ref>

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== Cost ==
[[File:Mars Reconnaissance Orbiter Development and Prime Mission Costs, by fiscal year.svg|thumb|''MRO'' development and prime mission costs, by fiscal year]]

The total cost of the ''MRO'' through the end of its prime mission was {{US$|716.6 million|long=no}}. Of this amount, {{US$|416.6 million|long=no}} was spent on spacecraft development, approximately {{US$|90 million|long=no}} for its launch, and {{US$|210 million|long=no}} for 5 years of mission operations. Since 2011, ''MRO''<nowiki/>'s annual operations costs are, on average, {{US$|31 million|long=no}} per year, when adjusted for inflation.<ref name="mro-cost">{{cite web |title=Cost of the Mars Reconnaissance Orbiter |url=https://www.planetary.org/explore/space-topics/mro-cost.html |url-status=live |archive-url=https://web.archive.org/web/20200803180627/https://www.planetary.org/explore/space-topics/mro-cost.html |archive-date=August 3, 2020 |access-date=April 24, 2020 |website=www.planetary.org |publisher=The Planetary Society |language=en}}</ref>

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== Discoveries ==

=== Ice ===
[[File:Ice exposed by impact.jpg|thumb|Water ice excavated by an impact crater that formed between January and September 2008. The ice was identified spectroscopically using CRISM.]]
An article in the journal ''Science'' in September 2009,<ref name="distribution"/> reported that some new craters on Mars have excavated relatively pure water ice. After being exposed, the ice gradually fades as it sublimates away. These new craters were found and dated by the CTX camera, and the identification of the ice was confirmed using CRISM. The ice was found in a five locations, three of which were in the [[Astronomy:Cebrenia quadrangle|Cebrenia quadrangle]]. These locations are {{coord|55.57|N|150.62|E|globe:mars}}; {{coord|43.28|N|176.9|E|globe:mars}}; and {{coord|45|N|164.5|E|globe:mars}}. Two others are in the [[Astronomy:Diacria quadrangle|Diacria quadrangle]]: {{coord|46.7|N|176.8|E|globe:mars}} and {{coord|46.33|N|176.9|E|globe:mars}}.<ref name="Water Ice Exposed in Mars Craters"/><ref name="NASA to Hold Teleconference to Discuss New Findings About Mars"/>

Radar results from SHARAD suggested that features termed [[Astronomy:Lobate debris apron|lobate debris apron]]s (LDAs) contain large amounts of water ice. Of interest from the days of the [[Engineering:Viking program|Viking]] Orbiters, these LDA are aprons of material surrounding cliffs. They have a convex topography and a gentle slope; this suggests flow away from the steep source cliff. In addition, lobate debris aprons can show surface lineations just as rock glaciers on the Earth.<ref>{{cite news |title=NASA Spacecraft Detects Buried Glaciers on Mars |url=https://www.jpl.nasa.gov/news/news.php?feature=1957 |work=NASA/JPL |date=November 20, 2008 |access-date=October 3, 2018 |archive-date=August 29, 2019 |archive-url=https://web.archive.org/web/20190829122308/https://www.jpl.nasa.gov/news/news.php?feature=1957 |url-status=live }}</ref> SHARAD has provided strong evidence that the LDAs in [[Astronomy:Hellas Planitia|Hellas Planitia]] are [[Earth:Glacier|glacier]]s that are covered with a thin layer of debris (i.e. rocks and dust); a strong reflection from the top and base of LDAs was observed, suggesting that pure water ice makes up the bulk of the formation (between the two reflections).<ref name="brown"/> Based on the experiments of the ''Phoenix'' lander and the studies of the ''Mars Odyssey'' from orbit, water ice is known to exist just under the surface of Mars in the far north and south (high latitudes).<ref>{{Cite web |date=June 20, 2008 |title=NASA Phoenix Mars Lander Confirms Frozen Water |url=https://www.nasa.gov/mission_pages/phoenix/news/phoenix-20080620.html |access-date=January 20, 2023 |website=NASA |archive-date=May 19, 2017 |archive-url=https://web.archive.org/web/20170519211159/https://www.nasa.gov/mission_pages/phoenix/news/phoenix-20080620.html |url-status=live }}</ref><ref>{{Cite web |date=May 28, 2002 |title=Odyssey Finds Water Ice in Abundance Under Mars' Surface |url=https://mars.nasa.gov/news/247/odyssey-finds-water-ice-in-abundance-under-mars-surface/ |access-date=January 20, 2023 |website=NASA Mars Exploration Program |archive-date=July 2, 2022 |archive-url=https://web.archive.org/web/20220702012401/https://mars.nasa.gov/news/247/odyssey-finds-water-ice-in-abundance-under-mars-surface/ |url-status=live }}</ref>

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=== Chloride deposits and aqueous minerals===
[[File:Chloride deposits on Mars.JPG|thumb|Chloride deposits in Terra Sirenum|209x209px]]
Using data from ''Mars Global Surveyor'', ''Mars Odyssey'', and the ''MRO'', scientists have found widespread deposits of chloride minerals. Evidence suggests that the deposits were formed from the evaporation of mineral enriched waters. The research suggests that lakes may have been scattered over large areas of the Martian surface. Usually, chlorides are the last minerals to come out of [[Chemistry:Solution|solution]]. Carbonates, sulfates, and silica should precipitate out ahead of them. Sulfates and silica have been found by the Mars rovers on the surface. Places with chloride minerals may have once held various life forms. Furthermore, such areas could preserve traces of ancient life.<ref name="materials"/>

In 2009, a group of scientists from the CRISM team reported on nine to ten different classes of minerals formed in the presence of water. Different types of clays (also called phyllosilicates) were found in many locations. The phyllosilicates identified included aluminum smectite, iron/magnesium smectite, [[Chemistry:Kaolinite|kaolinite]], [[Chemistry:Prehnite|prehnite]], and [[Chemistry:Chlorite group|chlorite]]. Rocks containing carbonate were found around the Isidis basin. Carbonates belong to one class in which life could have developed. Areas around [[Astronomy:Valles Marineris|Valles Marineris]] were found to contain hydrated [[Chemistry:Silica|silica]] and hydrated sulfates. The researchers identified hydrated sulfates and ferric minerals in Terra Meridiani and in Valles Marineris. Other minerals found on Mars were [[Chemistry:Jarosite|jarosite]], [[Chemistry:Alunite|alunite]], [[Chemistry:Hematite|hematite]], [[Chemistry:Opal|opal]], and [[Chemistry:Gypsum|gypsum]]. Two to five of the mineral classes were formed with the right [[Chemistry:PH|pH]] and sufficient water to permit life to grow.<ref name="reconnaissance"/>

=== Recurring slope lineae ===
[[File:Seasonal Changes in Dark Marks on an Equatorial Martian Slope.gif|thumb|Images from HiRISE showing the appearance of dark marks on the floor of Valles Marineris. Images taken at various times in the year.]]{{See also|Seasonal flows on warm Martian slopes}}
On August 4, 2011 (sol {{age in sols|2005|08|12|2011|08|04}}), NASA announced that ''MRO'' had detected [[Astronomy:Dark slope streak|dark streaks on slopes]], known as ''recurring slope lineae'' caused by what appeared to be [[Astronomy:Seasonal flows on warm Martian slopes|flowing salty water]] on the surface or subsurface of Mars.<ref name="scienceblog" /> On September 28, 2015, this finding was confirmed at a special NASA news conference.<ref>{{cite news |last=Chang |first=Kenneth |date=September 28, 2015 |title=NASA Says Signs of Liquid Water Flowing on Mars |work=The New York Times |url=https://www.nytimes.com/2015/09/29/science/space/mars-life-liquid-water.html?_r=0 |url-status=live |url-access=subscription |access-date=September 28, 2015 |archive-url=https://web.archive.org/web/20150930054305/http://www.nytimes.com/2015/09/29/science/space/mars-life-liquid-water.html?_r=0 |archive-date=September 30, 2015 |quote=Christopher P. McKay, an astrobiologist at NASA's Ames Research Center, does not think the R.S.L.s are a very promising place to look. For the water to be liquid, it must be so salty that nothing could live there, he said. "The short answer for habitability is it means nothing," he said.}}</ref><ref name="Ojha NG2015">{{cite journal |last1=Ojha |first1=Lujendra |last2=Wilhelm |first2=Mary Beth |last3=Murchie |first3=Scott L. |last4=McEwen |first4=Alfred S. |display-authors=0 |date=September 28, 2015 |title=Spectral evidence for hydrated salts in recurring slope lineae on Mars |journal=Nature Geoscience |volume=8 |issue=11 |pages=829–832 |bibcode=2015NatGe...8..829O |doi=10.1038/ngeo2546}}</ref> In 2017, however, further research suggested that the dark streaks were created by grains of sand and dust slipping down slopes, and not water darkening the ground.<ref>{{Cite web |last=Greicius |first=Tony |date=November 20, 2017 |title=Recurring Martian Streaks: Flowing Sand, Not Water? |url=https://www.nasa.gov/feature/jpl/recurring-martian-streaks-flowing-sand-not-water |access-date=July 19, 2023 |website=[[Organization:NASA|NASA]] |archive-date=December 8, 2021 |archive-url=https://web.archive.org/web/20211208070556/https://www.nasa.gov/feature/jpl/recurring-martian-streaks-flowing-sand-not-water |url-status=live }}</ref>

{{Clear}}

== See also ==
* {{annotated link|Astronomy:Exploration of Mars}}
* {{Annotated link|HiWish program}}

== Notes ==
{{notelist}}

== References ==
{{NASA}}
{{Reflist|refs=
<!--
<ref name="2008gl035790">Russell, P. et al. (2008). Seasonally active frost-dust avalanches on a north polar scarp of Mars captured by HiRISE. Geophysical Research Letters 35, {{doi|10.1029/2008GL035790}}.</ref>
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<ref name="aero">{{cite web |url=http://mars.jpl.nasa.gov/mro/mission/tl_aerobraking.html|title= Mission Timeline: Aerobraking|work=Mars Reconnaissance Orbiter: The Mission|access-date=May 28, 2006|archive-url=https://web.archive.org/web/20060306221449/http://mars.jpl.nasa.gov/mro/mission/tl_aerobraking.html|archive-date=March 6, 2006}}</ref>

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<ref name="AW">{{cite journal|last=Morris|first=Jefferson|date=January 4, 2010|title=Power Cycle|journal=Aviation Week|publisher=McGraw-Hill|page=17}}</ref>

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<ref name="distribution">Byrne, S. et al. 2009. ''Distribution of Mid-Latitude Ground Ice on Mars from New Impact Craters'': 329.1674–1676</ref>

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<ref name="HiRISE: Instrument Development">{{cite web|url=http://marsoweb.nas.nasa.gov/HiRISE/papers/6th_int_mars_conf/Delamere_HiRISE_InstDev.pdf|title=HiRISE: Instrument Development|work=NASA Ames Research Center website|access-date=February 7, 2006|archive-date=May 10, 2013|archive-url=https://web.archive.org/web/20130510160740/http://marsoweb.nas.nasa.gov/HiRISE/papers/6th_int_mars_conf/Delamere_HiRISE_InstDev.pdf|url-status=live}} (PDF)</ref>

<ref name="HiRISE">{{cite web|url=http://hirise.lpl.arizona.edu/|title=HiRISE|work=HiRISE website|access-date=May 28, 2006|archive-date=November 15, 2019|archive-url=https://web.archive.org/web/20191115222701/https://hirise.lpl.arizona.edu/|url-status=live}}</ref>

<ref name="ILS To Launch Mars Reconnaissance Orbiter For NASA On Atlas V">{{cite web|url=http://www.ilslaunch.com/newsarchives/newsreleases/rec312/|title= ILS To Launch Mars Reconnaissance Orbiter For NASA on Atlas V|work=International Launch Services|access-date=June 30, 2006|archive-url=https://web.archive.org/web/20060311060112/http://www.ilslaunch.com/newsarchives/newsreleases/rec312/|archive-date=March 11, 2006}}</ref>

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<ref name="Mars Orbiter Successfully Makes Big Burn">{{cite web|url=http://www.space.com/missionlaunches/060830_mro_brake.html|title=Mars Orbiter Successfully Makes Big Burn|website=Space.com|date=August 30, 2006|access-date=August 30, 2006|archive-date=July 8, 2008|archive-url=https://web.archive.org/web/20080708222136/http://www.space.com/missionlaunches/060830_mro_brake.html|url-status=live}}</ref>

<ref name="Mars Reconnaissance Orbiter Reaches Planned Flight Path">{{cite web|url=http://mars.jpl.nasa.gov/mro/newsroom/pressreleases/20060912a.html|title=Mars Reconnaissance Orbiter Reaches Planned Flight Path|work=[[Organization:JPL|JPL]]|access-date=September 13, 2006|archive-date=September 28, 2006|archive-url=https://web.archive.org/web/20060928225621/http://mars.jpl.nasa.gov/mro/newsroom/pressreleases/20060912a.html|url-status=live}}</ref>


<ref name="materials">Osterloo, M. et al. 2008. Chloride-Bearing Materials in the Southern Highlands of Mars. ''Science''. 319:1651–1654</ref>

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<ref name="Moving Day For Mars Reconnaissance Orbiter">{{cite web|url=http://www.space.com/missionlaunches/050501_mro_ksc.html|title=Moving Day For Mars Reconnaissance Orbiter|work=Space.com|date=May 2005|access-date=July 4, 2006|archive-date=November 25, 2006|archive-url=https://web.archive.org/web/20061125031156/http://www.space.com/missionlaunches/050501_mro_ksc.html|url-status=live}}</ref>

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<ref name="MRO HiRISE Camera Specifications">{{cite web|url=http://marsoweb.nas.nasa.gov/HiRISE/instrument.html#components|title=MRO HiRISE Camera Specifications|work=HiRISE website|access-date=January 2, 2006|archive-date=May 10, 2013|archive-url=https://web.archive.org/web/20130510124918/http://marsoweb.nas.nasa.gov/HiRISE/instrument.html#components|url-status=live}}</ref>

<ref name="MRO Waveguide Transfer Switch Anomaly">{{cite web |url=http://www.nasa.gov/offices/oce/llis/imported_content/lesson_1796.html |title=MRO Waveguide Transfer Switch Anomaly  |archive-url=https://web.archive.org/web/20130510130429/http://www.nasa.gov/offices/oce/llis/imported_content/lesson_1796.html |archive-date=May 10, 2013 }}</ref>

<ref name="msss2">{{Cite web |url=http://www.msss.com/mro/marci/images/2006/04/13/marci_detail/index.html |title=Mars Color Imager: How MARCI Takes Color Images, MRO MARCI Release No. MARCI2-3, 13 April 2006 |access-date=March 13, 2012 |archive-date=May 13, 2013 |archive-url=https://web.archive.org/web/20130513144512/http://www.msss.com/mro/marci/images/2006/04/13/marci_detail/index.html |url-status=live }}</ref>

<ref name="NASA Picks Lockheed Martin to Build 2005 Mars Craft">{{cite web|url=http://www.space.com/scienceastronomy/solarsystem/mro_lockheed_011003.html |title=NASA Picks Lockheed Martin to Build 2005 Mars Craft |work=Space.com |access-date=July 4, 2006  |archive-url=https://web.archive.org/web/20060212195951/http://www.space.com/scienceastronomy/solarsystem/mro_lockheed_011003.html |archive-date=February 12, 2006 }}</ref>

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<ref name="NASA's Multipurpose Mars Mission Successfully Launched">{{cite web|url=http://mars.jpl.nasa.gov/mro/newsroom/pressreleases/20050812a.html |title=NASA's Multipurpose Mars Mission Successfully Launched |work=NASA Press Release from August 12, 2005 |access-date=May 30, 2006  |archive-url=https://web.archive.org/web/20130510140909/http://mars.jpl.nasa.gov/mro/newsroom/pressreleases/20050812a.html |archive-date=May 10, 2013 }}</ref>

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<ref name="spp">{{cite web|url=http://mars.jpl.nasa.gov/mro/mission/sc_propulsion.html|title=Spacecraft Parts: Propulsion|work=NASA's MRO website| access-date =May 28, 2006 |archive-url = https://web.archive.org/web/20060331051038/http://mars.jpl.nasa.gov/mro/mission/sc_propulsion.html |archive-date = March 31, 2006}}</ref>


<ref name="U.S. Spacecraft Enters Orbit Around Mars">{{cite news|url=https://www.nytimes.com/2006/03/11/science/11plane.html?ex=1299733200&en=2edeb45e31198f5e&ei=5089&partner=rssyahoo&emc=rss|title=U.S. Spacecraft Enters Orbit Around Mars|newspaper={{wipe|New York Times}}|date=March 11, 2006|access-date=March 31, 2012|first=Warren E.|last=Leary|archive-date=April 24, 2009|archive-url=https://web.archive.org/web/20090424043444/http://www.nytimes.com/2006/03/11/science/11plane.html?ex=1299733200&en=2edeb45e31198f5e&ei=5089&partner=rssyahoo&emc=rss|url-status=live|url-access=subscription}}</ref>

<ref name="Water Ice Exposed in Mars Craters">{{cite news | author=Andrea Thompson | title=Water Ice Exposed in Mars Craters | url=http://www.space.com/scienceastronomy/090924-mars-crater-ice.html | work=Space.com | date=September 24, 2009 | access-date=September 2, 2011 | archive-date=December 25, 2010 | archive-url=https://web.archive.org/web/20101225015216/http://www.space.com/scienceastronomy/090924-mars-crater-ice.html | url-status=live }}</ref>
<!--Unused citation
<ref name="Spacecraft Parts: Electra">{{cite web|url=http://marsprogram.jpl.nasa.gov/mro/mission/sc_instru_electra.html|archive-url=https://web.archive.org/web/20040221222233/http://marsprogram.jpl.nasa.gov/mro/mission/sc_instru_electra.html|archive-date=February 21, 2004|title=Spacecraft Parts: Electra|work=Mars Reconnaissance Orbiter Website|access-date=February 20, 2005}}</ref>
-->
}}

== Further reading ==
* {{cite book |last1=Hubbard |first1=Scott |title=Exploring Mars: Chronicles from a Decade of Discovery |date=2012 |publisher=University of Arizona Press |isbn=978-0-8165-2896-7 |url=https://uapress.arizona.edu/book/exploring-mars|ref=none}}
* {{cite book | author=Squyres, Steve | year=2005 | title=Roving Mars: Spirit, Opportunity, and the Exploration of the Red Planet | isbn=978-1-4013-0149-1 | publisher=Hyperion | location=New York | url-access=registration | url=https://archive.org/details/rovingmarsspirit00squy |ref=none}}
* {{cite book |author1=Read, Peter L.  |author2=Lewis, Steven L.  |name-list-style=amp | year=2004 | title=The Martian Climate Revisited: Atmosphere and Environment of a Desert Planet | isbn=978-3-540-40743-0 | publisher=Springer | location=Berlin |ref=none}}

== External links ==

===Official instrument websites===
* [https://www.uahirise.org/ HiRISE website] from The University of Arizona
* [http://www.msss.com/mro/ctx/index.html CTX website] from [[Company:Malin Space Science Systems|Malin Space Science Systems]]
* [http://www.msss.com/mro/marci/index.html MARCI website] from Malin Space Science Systems
* [https://mars.nasa.gov/mro/mission/instruments/sharad/ SHARAD website] from NASA
* [http://crism.jhuapl.edu/ CRISM website] from Johns Hopkins University Applied Physics Laboratory

===Images===
* [http://photojournal.jpl.nasa.gov/spacecraft/MRO ''MRO'' images at the JPL Photojournal]
* [https://www.nasa.gov/mission_pages/MRO/images/index.html ''MRO'' images at the NASA Image Gallery]


[[Category:Mars Exploration Program]]
[[Category:Lockheed Martin satellites and probes|Mars Reconnaissance]]
[[Category:Missions to Mars|Reconnaissance]]
[[Category:NASA space probes|Mars Reconnaissance]]

{{Sourceattribution|Mars Reconnaissance Orbiter}}