Editing Mars Reconnaissance Orbiter (section)

== Instruments ==
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| image1            = Mars Reconnaissance Orbiter HiRISE.jpg
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| caption1          = High Resolution Imaging Science Experiment (HiRISE)
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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 |archive-date=August 18, 2023 |archive-url=https://web.archive.org/web/20230818200521/https://mars.nasa.gov/resources/7741/mars-reconnaissance-orbiter-by-the-numbers/ |url-status=live }}</ref>

=== HiRISE ===
{{Main|HiRISE}}

The High Resolution Imaging Science Experiment (HiRISE) camera is a {{convert|0.5|m|abbr=on}} [[reflecting telescope]], the largest ever carried on a [[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, [[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]]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 [[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 [[megapixel]]s) 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 [[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]] 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 [[Photographic mosaic|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]] <!-- diameter unknown -->[[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 [[Mars Reconnaissance Orbiter#Electronic systems|main computer]].<ref name="MRO Context Imager (CTX) Instrument Description"/> The camera was built, and is operated by [[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|Mars Color Imager}}

The '''Mars Color Imager (MARCI)''' is a wide-angle, relatively low-resolution camera that views the surface of Mars in five [[visible light|visible]] and two [[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 [[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 [[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 ===
{{Main|CRISM}}

The '''Compact Reconnaissance Imaging Spectrometer for Mars (CRISM)''' instrument is a [[VNIR|visible and near infrared]] [[spectrometer]] that is used to produce detailed maps of the surface [[mineralogy]] of Mars.<ref name="CRISM Instrument Overview"/> It operates from 362 to 3920&nbsp;nm, measures the [[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 [[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)''' is a radiometer that looks both down and horizontally through the atmosphere in order to quantify the [[Atmosphere of Mars#Vertical structure|atmosphere's vertical variations]]. It has one visible/near infrared channel (0.3 to 3.0&nbsp;μm) and eight [[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 [[Climate of Mars|Martian weather]]: temperature, pressure, humidity, and [[Martian soil#Atmospheric dust|dust density]].<ref name="Spacecraft Parts: Instruments: MCS"/> The MCS weighs roughly {{Convert|9|kg|lb|abbr=on}} and began operation in November 2006.<ref>{{Cite book |last=Jau |first=Bruno M. |chapter=Mechanical Description of the Mars Climate Sounder Instrument |date=March 2008 |title=2008 IEEE Aerospace Conference |chapter-url=http://dx.doi.org/10.1109/aero.2008.4526543 |pages=1–8 |publisher=[[IEEE]] |doi=10.1109/aero.2008.4526543|isbn=978-1-4244-1487-1 }}</ref><ref>{{Cite web |title=MRO Science Instruments |url=https://science.nasa.gov/mission/mars-reconnaissance-orbiter/science-instruments/ |access-date=2024-07-01 |website=[[NASA]] |language=en-US |archive-date=June 29, 2024 |archive-url=https://web.archive.org/web/20240629230542/https://science.nasa.gov/mission/mars-reconnaissance-orbiter/science-instruments/ |url-status=live }}</ref> Since beginning operation, it has helped create maps of mesospheric clouds,<ref>{{Cite web |last=Lea |first=Robert |date=2023-11-06 |title=Citizen scientists detect patterns in clouds over Mars |url=https://www.space.com/mars-clouds-citizen-science-cloudspotting |access-date=2024-07-01 |website=[[Space.com]] |language=en |archive-date=December 9, 2023 |archive-url=https://web.archive.org/web/20231209235457/https://www.space.com/mars-clouds-citizen-science-cloudspotting |url-status=live }}</ref> study and categorize dust storms,<ref>{{Cite journal |last1=Kass |first1=D. M. |last2=Schofield |first2=J. T. |last3=Kleinböhl |first3=A. |last4=McCleese |first4=D. J. |last5=Heavens |first5=N. G. |last6=Shirley |first6=J. H. |last7=Steele |first7=L. J. |date=2020-12-16 |title=Mars Climate Sounder Observation of Mars' 2018 Global Dust Storm |url=https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2019GL083931 |journal=[[Geophysical Research Letters]] |language=en |volume=47 |issue=23 |doi=10.1029/2019GL083931 |bibcode=2020GeoRL..4783931K |issn=0094-8276 |access-date=July 1, 2024 |archive-date=May 6, 2023 |archive-url=https://web.archive.org/web/20230506183721/https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2019GL083931 |url-status=live |url-access=subscription }}</ref> and provide direct evidence of [[Dry ice#Extraterrestrial occurrence|carbon dioxide snow]] on Mars.<ref>{{Cite magazine |last=Cray |first=Daniel |date=2012-09-17 |title=Martian Blizzard! It's Snowing on the Red Planet |url=https://science.time.com/2012/09/17/martian-blizzard-its-snowing-on-the-red-planet/ |access-date=2024-07-01 |magazine=Time |language=en-US |issn=0040-781X |archive-date=March 5, 2024 |archive-url=https://web.archive.org/web/20240305004708/https://science.time.com/2012/09/17/martian-blizzard-its-snowing-on-the-red-planet/ |url-status=live }}</ref>

This instrument, supplied by NASA's [[Jet Propulsion Laboratory]] (JPL), is an updated version of a heavier, larger instrument originally developed at JPL for the 1992 ''[[Mars Observer]]'' and 1998 ''[[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.<ref>{{Cite journal |last1=McCleese |first1=D. J. |last2=Schofield |first2=J. T. |last3=Taylor |first3=F. W. |last4=Calcutt |first4=S. B. |last5=Foote |first5=M. C. |last6=Kass |first6=D. M. |last7=Leovy |first7=C. B. |last8=Paige |first8=D. A. |last9=Read |first9=P. L. |last10=Zurek |first10=R. W. |date=May 2007 |title=Mars Climate Sounder: An investigation of thermal and water vapor structure, dust and condensate distributions in the atmosphere, and energy balance of the polar regions |url=https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2006JE002790 |journal=[[Journal of Geophysical Research]] |language=en |volume=112 |issue=E05S06 |doi=10.1029/2006JE002790 |bibcode=2007JGRE..112.5S06M |issn=0148-0227}}</ref>

=== SHARAD ===
{{Main|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 [[ice cap]]s. It also gathers planet-wide information about underground layers of [[regolith]], [[rock (geology)|rock]], and [[ice]] that might be accessible from the surface. SHARAD emits [[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 [[MARSIS]] instrument, which has coarser resolution but penetrates to a much greater depth. Both SHARAD and MARSIS were made by the [[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 [[Electra (radio)|Electra]] communications package is a [[Ultra high frequency|UHF]] [[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> [[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 (moon)|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 |archive-date=August 21, 2023 |archive-url=https://web.archive.org/web/20230821210310/https://mars.nasa.gov/mro/mission/instruments/kaband/ |url-status=live }}</ref>

The Optical Navigation Camera images the Martian moons, [[Phobos (moon)|Phobos]] and [[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" /> It was subsequently turned off, but was turned back on in 2022 to collect data for a potential [[NASA-ESA Mars Sample Return]] mission.<ref name=":8" />{{Rp|page=11}}

Two additional science investigations are also on the spacecraft. The Gravity Field Investigation Package measures variations in the [[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" /> Due to decreased budgets, data collection ended in 2022.<ref name=":8" />{{Rp|page=8}}

The Atmospheric Structure Investigation used sensitive onboard [[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>