View source for Trace Gas Orbiter

{{Short description|Mars orbiter, part of ExoMars programme}}
{{Use British English|date=October 2016}}
{{update|date=March 2020}}
{{Infobox spaceflight
| name               = Trace Gas Orbiter

<!--image of the spacecraft/mission-->| image              = ExoMars 2016 TGO and EDM trans-small.png
| image_caption      = Artist's illustration of ExoMars 2016
| image_size         = 300px

<!--Basic details-->| mission_type       = [[List of Mars orbiters|Mars orbiter]]
| operator           = [[European Space Agency|ESA]]{{dot}}[[Roscosmos State Corporation|Roscosmos]]
| COSPAR_ID          = 2016-017A
| SATCAT             = 41388
| website            = http://exploration.esa.int/jump.cfm?oid=46475
| mission_duration   = Planned: 7 years<ref name="esaOverview">{{cite web |url=http://exploration.esa.int/mars/46124-mission-overview/ |title=ExoMars Trace Gas Orbiter and Schiaparelli Mission (2016) |publisher=European Space Agency |date=16 October 2016 |access-date=24 October 2016}}</ref><ref name="june2011">{{cite conference |title=2016 ESA/NASA ExoMARS/Trace Gas Orbiter |conference=Mars Exploration Program Assessment Group. 15–16 June 2011. Lisbon, Portugal. |first1=Mark A. |last1=Allen |first2=Olivier |last2=Witasse |date=2011|hdl = 2014/42148}}</ref> <br /> Elapsed: {{time interval|14 March 2016 09:31|show=ymd|sep=,}}

<!--Spacecraft properties-->| manufacturer       = [[Thales Alenia Space]]
| launch_mass        = 4,332 kg<ref>{{cite web|url=https://nssdc.gsfc.nasa.gov/nmc/spacecraft/display.action?id=2016-017A |title=ExoMars 2016 |publisher=[[NASA Space Science Data Coordinated Archive]] |access-date=November 30, 2022}}</ref>
| dry_mass           = 
| payload_mass       = Instruments: {{convert|113.8|kg|lb|abbr=on}}<ref name="trace-gas-orbiter">{{cite web |url=http://exploration.esa.int/jump.cfm?oid=46475 |title=ExoMars Trace Gas Orbiter (TGO) |publisher=European Space Agency |date=12 July 2012 |access-date=8 March 2014}}</ref> <br /> ''Schiaparelli'': {{convert|577|kg|lb|abbr=on}}<ref name="trace-gas-orbiter" />
| dimensions         = {{convert|3.2|xx|2|xx|2|m|ft|abbr=on}}<ref name="trace-gas-orbiter" />
| power              = ~2000&nbsp;W<ref name="trace-gas-orbiter" />

<!--Launch details-->| launch_date        = {{start-date|14 March 2016, 09:31}}&nbsp;[[UTC]]<ref name="bbcnews20160314" />
| launch_rocket      = [[Proton-M]]/[[Briz-M]]
| launch_site        = [[Baikonur Cosmodrome|Baikonur]] [[Baikonur Cosmodrome Site 200|200/39]]
| launch_contractor  = [[Khrunichev State Research and Production Space Center|Khrunichev]]

<!--orbit parameters-->| orbit_reference    = [[Areocentric orbit|Areocentric]]
| orbit_regime       = [[Circular orbit|Circular]]
| orbit_semimajor    = <!--semimajor axis-->
| orbit_eccentricity = 0
| orbit_periapsis    = {{convert|400|km|mi|abbr=on}}
| orbit_apoapsis     = {{convert|400|km|mi|abbr=on}}
| orbit_inclination  = 74&nbsp;degrees
| orbit_period       = 2&nbsp;hours
| orbit_epoch        = Planned
| apsis              = areion
| interplanetary     = {{Infobox spaceflight/IP
 | type                 = orbiter
 | object               = Mars
 | arrival_date         = 19 October 2016, 15:24&nbsp;UTC<ref>{{cite news |url=http://www.spaceflightinsider.com/missions/solar-system/lost-mars-schiaparelli-lander-falls-silent-shortly-touchdown/ |title=Lost on Mars: Schiaparelli lander falls silent shortly before touchdown |work=Spaceflight Insider |first=Tomasz |last=Nowakowski |date=20 October 2016 |access-date=24 October 2016 |archive-date=27 October 2016 |archive-url=https://web.archive.org/web/20161027010922/https://www.spaceflightinsider.com/missions/solar-system/lost-mars-schiaparelli-lander-falls-silent-shortly-touchdown/}}</ref>
 }}
| instruments_list   = {{Infobox spaceflight/Instruments
  | acronym1 = NOMAD  | name1 = [[Nadir and Occultation for Mars Discovery]]
  | acronym2 = ACS    | name2 = Atmospheric Chemistry Suite
  | acronym3 = CaSSIS | name3 = Colour and Stereo Surface Imaging System
  | acronym4 = FREND  | name4 = Fine-Resolution Epithermal Neutron Detector
 }}

<!--mission insignia or patch-->| insignia           = File:ExoMars 2016 insignia.png
| insignia_caption   = [[ESA]] mission insignia for the ''ExoMars 2016'' launch, featuring the ''Trace Gas Orbiter'' (left) and ''Schiaparelli'' (right)
| insignia_alt       = 
| insignia_size      = 80px

<!--transponder parameters-->| trans_band         = [[X band]]<br />[[Electra (radio)|UHF band]]
| trans_frequency    = 390–450 [[Hertz|MHz]]
| trans_bandwidth    = <!--bandwidth-->
| trans_capacity     = <!--capacity of the transponders-->
| trans_coverage     = <!--area covered-->
| trans_TWTA         = 65 W
| trans_EIRP         = <!--equivalent isotropic power-->
| trans_HPBW         = <!--half-power beam width-->

<!--Only use where a spacecraft/mission is part of a clear programme of sequential missions.
If in doubt, leave it out-->| programme          = [[ExoMars]] programme
| previous_mission   = 
| next_mission       = [[Rosalind Franklin (rover)|''Rosalind Franklin'' rover]]
}}

The '''ExoMars Trace Gas Orbiter''' ('''TGO''' or '''ExoMars Orbiter''') is a collaborative project between the [[European Space Agency]] (ESA) and the Russian [[Roscosmos]] agency that sent an [[atmospheric science|atmospheric research]] [[orbiter]] and the [[Schiaparelli EDM|''Schiaparelli'']] demonstration lander to [[Mars]] in 2016 as part of the European-led [[ExoMars]] programme.<ref name="NYT-20161019">{{cite news |last=Chang |first=Kenneth |title=ExoMars Mission to Join Crowd of Spacecraft at Mars |url=https://www.nytimes.com/2016/10/20/science/esa-mars-lander.html |date=19 October 2016 |work=[[The New York Times]] |access-date=19 October 2016}}</ref><ref name="tbthStatus">{{Citation |first=J. L. |last=Vago |contribution=Mars Panel Meeting |title=Planetary Science Decadal Survey |publisher=[[European Space Agency]] |place=Arizona State University, Tempe (US) |date=10 September 2009 |contribution-url=http://www.marspages.eu/media/archive4/exomars/statusbericht/StatusberichtSep2009.pdf|contribution-format=PDF}}</ref><ref name="Mustard">{{cite web |url=http://www.lpi.usra.edu/pss/july2009/presentations/05MEPAG.pdf |title=MEPAG Report to the Planetary Science Subcommittee |publisher=Mars Exploration Program Analysis Group |first=Jack |last=Mustard |page=3 |date=9 July 2009 |archive-date=4 September 2012 |archive-url=https://web.archive.org/web/20120904082337/https://www.lpi.usra.edu/pss/july2009/presentations/05MEPAG.pdf}}</ref> A key goal is to gain a better understanding of [[Methane on Mars|methane]] ({{chem2|CH4}}) and other trace gases present in the [[Atmosphere of Mars|Martian atmosphere]] that could be evidence for possible biological activity.

The Trace Gas Orbiter delivered the [[Schiaparelli EDM|''Schiaparelli'' lander]] on 16 October 2016, which crashed on the surface due to a premature release of the parachute.<ref name=BBC_20_Oct_2016>{{cite news |url=https://www.bbc.co.uk/news/science-environment-37707776 |title=Fears grow for European Schiaparelli Mars lander |first=Jonathan |last=Amos |work=BBC News |date=19 October 2016 |access-date=20 October 2016}}</ref> TGO has been orbiting Mars since October 2016 and performing science observations of the planet since April 2018.<ref name="esa20180426" />

The [[ExoMars]] programme will continue with the [[Rosalind Franklin (rover)|''Rosalind Franklin'' rover]] in 2028,<ref>{{Cite web |last=Foust |first=Jeff |date=2024-04-10 |title=ESA awards contract to Thales Alenia Space to restart ExoMars |url=http://spacenews.com/esa-awards-contract-to-thales-alenia-space-to-restart-exomars/ |access-date=2025-06-01 |website=SpaceNews |language=en-US}}</ref> which will search for [[biomolecule]]s and [[biosignature]]s; the TGO will operate as the communication link for the lander and rover and provide communication for other Mars surface probes with Earth.

== Specifications ==
[[File:ExoMars TGO size vs Mars Express.svg|thumb|right|Size of the Trace Gas Orbiter (left) with the ''Schiaparelli'' EDM attached, compared to ''[[Mars Express]]'' (right) and an average human]]
[[File:Maquette Exomars Orbiter Salon du Bourget 2015 DSC 0045.jpg|thumb|Scale model of the ''ExoMars Trace Gas Orbiter'' displayed during the [[Paris Air Show]], 2015]]
;Dimensions: The central [[Satellite bus|bus]] is {{convert|3.2|×|2|×|2|m|ft|abbr=on}}<ref name="trace-gas-orbiter" />
;Propulsion: {{convert|424|N|lbf|lk=on|abbr=on}} [[Liquid-propellant rocket|bi-propellant]] main engine, used for Mars orbit insertion and manoeuvres<ref name="trace-gas-orbiter" />
;Power: {{convert|20|m2|sqft|abbr=on}} [[solar array]]s spanning {{convert|17.5|m|ft|0|abbr=on}} tip-to-tip, and capable of rotating in one axis;<ref name="tgosfk">{{Cite web |date=2016-09-26 |title=Trace Gas Orbiter (TGO) Spacecraft Frames Kernel |url=https://naif.jpl.nasa.gov/pub/naif/EXOMARS2016/kernels/fk/em16_tgo_v08.tf |access-date=2018-10-06}}</ref> generates about 2,000 [[Watt|W]] of power at Mars<ref name="trace-gas-orbiter" />
;Batteries: 2 modules of [[Lithium-ion battery|lithium-ion batteries]] with approximately 5100 [[watt hour]]s total capacity to provide power during eclipses over the prime mission<ref name="trace-gas-orbiter" />
;Communication: {{convert|2.2|m|ftin|abbr=on}} [[X band]] [[high-gain antenna]] with a two-axis pointing mechanism and 65 [[Watt|W]] [[Radio frequency|RF]] [[Traveling-wave tube|travelling-wave tube amplifier]] to communicate with Earth<ref name="trace-gas-orbiter" />
: Two [[Electra (radio)|Electra]] [[Ultra high frequency|UHF band]] [[transceiver]]s with a single [[helical antenna]] to communicate with spacecraft at Mars<ref name="trace-gas-orbiter" />
;Thermal control: Spacecraft [[Aircraft principal axes#Vertical axis (yaw)|yaw axis]] control to ensure the three faces containing the science payload remain cold
;Mass: {{convert|3755|kg|lb|abbr=on}}, [[wet mass]] of the orbiter<ref name="trace-gas-orbiter" />
: {{convert|4332|kg|lb|abbr=on}}, wet mass of the orbiter plus ''Schiaparelli'' lander<ref name="trace-gas-orbiter" />
;Payload: {{convert|113.8|kg|lb|abbr=on}} of science instruments<ref name="trace-gas-orbiter" />

== Instruments ==
[[File:CaSSIS.jpg|thumb|Colour and Stereo Surface Imaging System (CaSSIS)]]
Like the ''[[Mars Reconnaissance Orbiter]]'', the Trace Gas Orbiter is a hybrid science and telecom orbiter.<ref name="Vago">{{cite news |last=Vago |first=J. |display-authors=etal |date=August 2013 |title=ExoMars, ESA's next step in Mars exploration |url=http://esamultimedia.esa.int/multimedia/publications/ESA-Bulletin-155/offline/download.pdf |work=ESA Bulletin |pages=12–23 |issue=155}}</ref> Its scientific payload mass is about {{convert|113.8|kg|lb|abbr=on}} and consists of:<ref name="trace-gas-orbiter" /><ref name="paylod2014">{{cite web |date=20 February 2014 |title=ExoMars Trace Gas Orbiter Instruments |url=http://exploration.esa.int/mars/48523-trace-gas-orbiter-instruments/ |url-status=dead |archive-url=https://web.archive.org/web/20160219211336/http://exploration.esa.int/mars/48523-trace-gas-orbiter-instruments/ |archive-date=19 February 2016 |access-date=8 March 2014 |work=ESA}}</ref>

* The [[Nadir and Occultation for Mars Discovery]] ('''NOMAD''') has two [[infrared]] and one [[ultraviolet]] [[spectrometer]] channels.<ref>{{cite journal |last1=Thomas |first1=I. R. |last2=Vandaele |first2=A. C. |last3=Neefs |first3=E. |last4=Ristic |first4=B. |last5=Hetey |first5=L. |last6=Mahieux |first6=A. |last7=Robert |first7=S. |last8=Daerden |first8=F. |last9=Depiesse |first9=C. |last10=Mason |first10=J. P. |last11=Patel |first11=M. R. |last12=Lopez Moreno |first12=J. J. |last13=Bellucci |first13=G. |display-authors=3 |date=2017 |title=The NOMAD Spectrometer Suite on the ExoMars 2016 Orbiter: Current Status |url=http://www-mars.lmd.jussieu.fr/granada2017/abstracts/thomas_granada2017.pdf |journal=The Sixth International Workshop on the Mars Atmosphere: Modelling and Observation. 17–20 January 2017. Granada, Spain. |pages=4401 |bibcode=2017mamo.conf.4401T}}</ref>  Developed by Belgium.
* The [[Atmospheric Chemistry Suite]] ('''ACS''') has three infrared spectrometer channels.<ref name="ACS">{{cite news |last=Zakutnyaya |first=Olga |date=25 November 2012 |title=Europe to invest 12 bln euros in a new space Odyssey |url=http://www.spacedaily.com/reports/Europe_to_invest_12_bln_euros_in_a_new_space_Odyssey_999.html |website=Space Daily}}</ref><ref name="ria2014">{{cite news |date=4 August 2014 |title=Russia to Construct Landing Pad for Russian-European "ExoMars-2018" Space Mission |url=http://en.ria.ru/russia/20140804/191710468/Russia-to-Construct-Landing-Pad-for-Russian-European.html |access-date=5 August 2014 |work=RIA Novosti |location=Russia}}</ref> Developed by Russia.

*The Colour and Stereo Surface Imaging System ('''CaSSIS''') is a high-resolution, {{convert|4.5|m|ft|0|abbr=on|disp=x| per pixel (|/pixel)}}, colour stereo camera for building accurate digital elevation models of the Martian surface. It will also be an important tool for characterising candidate landing site locations for future missions. Developed by Switzerland.
*The [[Fine-Resolution Epithermal Neutron Detector]] ('''FREND''') is a neutron detector that can provide information on the presence of [[hydrogen]], in the form of water or hydrated minerals, in the top {{convert|1|m|ftin|abbr=on}} of the Martian surface.<ref name="ria2014" /> Developed by Russia.
NOMAD and ACS are providing the most extensive spectral coverage of Martian atmospheric processes so far.<ref name="Vago" /><ref name="onTrack">{{cite news |last=Amos |first=Jonathan |date=18 June 2013 |title=Europe |url=https://www.bbc.co.uk/news/science-environment-22914025 |access-date=18 June 2013 |website=BBC News}}</ref> Twice per orbit, at local sunrise and sunset, they are able to observe the Sun as it shines through the atmosphere. Detection of atmospheric trace species at the parts-per-billion (ppb) level are possible.

== Science ==
The FREND instrument is mapping hydrogen levels to a maximum depth of {{convert|1|m|ftin|abbr=on}} beneath the Martian surface.<ref name="Grayzeck">{{cite web |title=ExoMars 2016 |url=https://nssdc.gsfc.nasa.gov/nmc/spacecraft/display.action?id=2016-017A |access-date=15 March 2016 |work=[[National Space Science Data Center]] |publisher=NASA}}</ref><ref name="Gannon2016">{{cite news |last=Gannon |first=Megan |date=14 March 2016 |title=The Science of ExoMars: New Mission to Hunt for Mars Life |url=http://www.space.com/32250-exomars-mars-mission-science.html?adbid=10153371993821466&adbpl=fb&adbpr=17610706465 |access-date=16 March 2016 |work=Space.com}}</ref> Locations where hydrogen is found may indicate [[Water on Mars|water-ice deposits]], which could be useful for future crewed missions.

Particularly, the mission is characterising spatial, temporal variation, and localisation of sources for a broad list of [[Atmosphere of Mars|atmospheric trace gases]]. If [[Methane on Mars|methane]] ({{chem2|CH4}}) is found in the presence of [[propane]] ({{chem2|C3H8}}) or [[ethane]] ({{chem2|C2H6}}), that would be a strong indication that biological processes are involved.<ref name="ExoMars ACS">{{cite web |last=Montmessin |first=F. |title=Atmospheric Chemistry Suite: Science Overview |url=http://www.planetary-department-iki.ru/projects/future/acs/ACS_meeting/presentations/montmessin_Presentation1.pdf |url-status=dead |archive-url=https://web.archive.org/web/20160315035042/http://www.planetary-department-iki.ru/projects/future/acs/ACS_meeting/presentations/montmessin_Presentation1.pdf |archive-date=15 March 2016 |access-date=14 March 2016 |work=LATMOS CNRS, France |page=44 |quote=Determining the origin of methane on Mars can only be addressed by looking at methane isotopologues and at higher alkanes (ethane, propane).}}</ref> However, if methane is found in the presence of gases such as [[sulfur dioxide]] ({{chem2|SO2}}), that would be an indication that the methane is a byproduct of geological processes.<ref name="McKie 2016">{{cite news |last=McKie |first=Robin |date=20 February 2016 |title='Giant nose in the sky' ready for lift-off in mission to sniff out traces of life on Mars |url=https://www.theguardian.com/science/2016/feb/21/exomars-probe-life-mars-sniff-out-methane-rover |access-date=21 February 2016 |work=The Guardian}}</ref>

=== Detection ===
[[File:Martian Methane Map.jpg|thumb|Visualisation of a methane plume found in Mars' atmosphere during the northern summer season]]
The nature of the [[Methane on Mars|methane source]] requires measurements of a suite of trace gases in order to characterise potential biochemical and geochemical processes at work. The orbiter has very high sensitivity to (at least) the following molecules and their [[isotopomers]]: [[water]] ({{chem2|H2O}}), [[hydroperoxyl]] ({{chem2|HO2}}), [[nitrogen dioxide]] ({{chem2|NO2}}), [[nitrous oxide]] ({{chem2|N2O}}), [[methane]] ({{chem2|CH4}}), [[acetylene]] ({{chem2|C2H2}}), [[ethylene]] ({{chem2|C2H4}}), [[ethane]] ({{chem2|C2H6}}), [[formaldehyde]] ({{chem2|H2CO}}), [[hydrogen cyanide]] ({{chem2|HCN}}), [[hydrogen sulfide]] ({{chem2|H2S}}), [[carbonyl sulfide]] ({{chem2|OCS}}), [[sulfur dioxide]] ({{chem2|SO2}}), [[hydrogen chloride]] ({{chem2|HCl}}), [[carbon monoxide]] ({{chem2|CO}}) and [[ozone]] ({{chem2|O3}}). Detection sensitivities are at levels of 100 parts per trillion, improved to 10 parts per trillion or better by averaging spectra which could be taken at several spectra per second.<ref name="nomad2011">{{cite web |last=Vandaele |first=A. C. |display-authors=etal |title=NOMAD, a spectrometer suite for nadir and solar occultation observations on the ExoMars Trace Gas Orbiter |url=http://www-mars.lmd.jussieu.fr/paris2011/abstracts/vandaele_paris2011.pdf |access-date=4 September 2015 |publisher=Institut des NanoSciences de Paris}}</ref>

=== Characterisation ===
*Spatial and temporal variability: latitude–longitude coverage multiple times in a Mars year to determine regional sources and seasonal variations (reported to be large, but still controversial with present understanding of Mars gas-phase photochemistry)
*Correlation of concentration observations with environmental parameters of temperature, dust and ice aerosols (potential sites for heterogeneous chemistry)<ref name="trace-gas-orbiter" />

=== Localisation ===
*Mapping of multiple tracers (e.g., [[aerosol]]s, [[water vapour]], [[Carbon monoxide|CO]], [[Methane|{{chem2|CH4}}]]) with different photochemical lifetimes and correlations helps constrain model simulations and points to source/sink regions
*To achieve the spatial resolution required to localise sources might require tracing molecules at parts-per-billion concentrations

== Relay telecommunications ==
[[File:Pia17952 electra transceiver dsc09326 0.jpg|thumb|An [[Electra (radio)|Electra radio]], in this case the one for the ''MAVEN'' probe. Electra radios were also deployed on the ''Trace Gas Orbiter'' and on other Mars telecommunications assets.]]
Due to the challenges of entry, descent and landing, Mars landers are highly constrained in mass, volume and power. For landed missions, this places severe constraints on antenna size and transmission power, which in turn greatly reduce direct-to-Earth communication capability in comparison to orbital spacecraft. As an example, the capability downlinks on ''[[Spirit (rover)|Spirit]]'' and ''[[Opportunity (rover)|Opportunity]]'' rovers had only {{frac|1|600}} the capability of the ''[[Mars Reconnaissance Orbiter]]'' downlink. 

Relay communication addresses this problem by allowing Mars surface spacecraft to communicate using higher data rates over short-range links to nearby Mars orbiters, while the orbiter takes on the task of communicating over the long-distance link back to Earth. This relay strategy offers a variety of key benefits to Mars landers: increased data return volume, reduced energy requirements, reduced communications system mass, increased communications opportunities, robust critical event communications and ''in situ'' navigation aid.<ref>{{cite report |url=https://mepag.jpl.nasa.gov/reports/decadal/CharlesDEdwards.pdf |title=Relay Orbiters for Enhancing and Enabling Mars ''In Situ'' Exploration |last1=Edwards |first1=Charles D. Jr. |last2=Banerdt |first2=William B. |last3=Beaty |first3=David W. |last4=Tamppari |first4=Leslie K. |last5=Zurek |first5=Richard W. |date=15 September 2009 |publisher=Mars Exploration Program Analysis Group}}</ref> 

NASA provided an [[Electra (radio)|Electra telecommunications relay]] and navigation instrument to assure communications between probes and rovers on the surface of Mars and controllers on Earth.<ref>{{cite news |last=De Selding |first=Peter B. |date=26 September 2012 |title=U.S., Europe Won't Go It Alone in Mars Exploration |url=http://spacenews.com/us-europe-wont-go-it-alone-mars-exploration/ |access-date=27 September 2012 |website=Space News}}</ref> 

The TGO will provide the [[Rosalind Franklin (rover)|''Rosalind Franklin'' rover]] with telecommunications relay; it will also serve as a relay satellite for future lander missions.<ref name="june2011" />
== History ==
[[File:ExoMars 2016 Launch.jpg|thumb|Launch of the Proton carrier rocket]]
[[File:Animation of ExoMars Trace Gas Orbiter trajectory.gif |thumb|right| Animation of ExoMars Trace Gas Orbiter{{'s}} trajectory<br />{{legend2|Yellow| Sun}}{{·}}{{legend2|RoyalBlue| Earth}}{{·}}{{legend2|Lime| Mars}}{{·}}{{legend2|Magenta| ExoMars Trace Gas Orbiter }}]]
[[File:Animation of ExoMars Trace Gas Orbiter trajectory around Mars.gif |thumb|right| Animation of ExoMars Trace Gas Orbiter{{'s}} trajectory around Mars<br />{{legend2|Lime| Mars}}{{·}}{{legend2|Magenta| ExoMars Trace Gas Orbiter }}]]
Investigations with space and Earth-based observatories have demonstrated the presence of a small amount of [[Methane on Mars|methane]] on the atmosphere of Mars that seems to vary with location and time.<ref>{{cite web |url=http://mepag.jpl.nasa.gov/decadal/TGM_Mars_Panel-cleared-9-4-09.ppt |title=Mars Trace Gas Mission |publisher=MEPAG |date=10 September 2009 |url-status=dead |archive-url=https://web.archive.org/web/20110721052957/http://mepag.jpl.nasa.gov/decadal/TGM_Mars_Panel-cleared-9-4-09.ppt |archive-date=21 July 2011 |df=dmy-all}}</ref><ref name="plumes">{{Cite journal |title=Strong Release of Methane on Mars in Northern Summer 2003 |journal=Science |date=20 February 2009 |first1=Michael J. |last1=Mumma |last2=Villanueva |first2=Gerónimo L. |volume=323 |issue=5917 |pages=1041–1045 |doi=10.1126/science.1165243 |url=http://images.spaceref.com/news/2009/Mumma_et_al_Methane_Mars_wSOM_accepted2.pdf |pmid=19150811 |bibcode=2009Sci...323.1041M |last3=Novak |first3=Robert E. |last4=Hewagama |first4=Tilak |last5=Bonev |first5=Boncho P. |last6=Disanti |first6=Michael A. |last7=Mandell |first7=Avi M. |last8=Smith |first8=Michael D.|s2cid=25083438 }}</ref><ref>{{Cite news |first=Eric |last=Hand |title=Plumes of methane identified on Mars |date=21 October 2008 |publisher=Nature News |url=http://esse.engin.umich.edu/psl/PRESS/Mars/NatureNews_2008.pdf |access-date=2 August 2009 }}</ref> This may indicate the presence of microbial [[life on Mars (planet)|life on Mars]], or a [[geochemical]] process such as [[volcanism]] or [[hydrothermal activity]].<ref>{{cite news |url=http://astrobio.net/news/modules.php?op=modload&name=News&file=article&sid=2765&mode=thread&order=0&thold=0 |title=Making Sense of Mars' Methane |date=June 2008 |website=Astrobio.net |access-date=19 March 2012 |archive-date=23 September 2008 |archive-url=https://web.archive.org/web/20080923195833/http://astrobio.net/news/modules.php?op=modload&name=News&file=article&sid=2765&mode=thread&order=0&thold=0 |url-status=dead }}</ref><ref>{{Cite news |first=Bill |last=Steigerwald |title=Martian Methane Reveals the Red Planet is not a Dead Planet |date=15 January 2009 |publisher=NASA |url=http://www.nasa.gov/mission_pages/mars/news/marsmethane.html |work=NASA's Goddard Space Flight Center |access-date=24 January 2009 |archive-date=21 February 2009 |archive-url=https://web.archive.org/web/20090221030541/https://www.nasa.gov/mission_pages/mars/news/marsmethane.html}}</ref><ref name="Howe">{{Cite conference |last1=Howe |first1=K. L. |last2=Gavin |first2=P. |last3=Goodhart |first3=T. |last4=Kral |first4=T. A. |title=Methane Production by Methanogens in Perchlorate-Supplemented Media. |conference=40th Lunar and Planetary Science Conference |date=2009 |url=http://www.lpi.usra.edu/meetings/lpsc2009/pdf/1287.pdf }}</ref><ref name="Levin2009">{{Cite journal |title=Methane and life on Mars |journal=Proc. SPIE |date=3 September 2009 |first1=Gilbert V. |first2=Patricia Ann |last2=Straat |volume=7441 |issue=74410D |pages=74410D |doi=10.1117/12.829183 |last1=Levin |series=Proceedings of SPIE |bibcode=2009SPIE.7441E..0DL|s2cid=73595154 }}</ref>

The challenge to discern the source of methane in the atmosphere of Mars prompted the independent planning by ESA and NASA of one orbiter each that would carry instruments in order to determine if its formation is of biological or geological origin,<ref>{{Cite news |first=Paul |last=Rincon |title=Agencies outline Mars initiative |date=9 July 2009 |url=http://news.bbc.co.uk/2/hi/science/nature/8130393.stm |website=BBC News |access-date=26 July 2009}}</ref><ref>{{Cite news |title=NASA orbiter to hunt for source of Martian methane in 2016 |date=6 March 2009 |url=http://www.thaindian.com/newsportal/health/nasa-orbiter-to-hunt-for-source-of-martian-methane-in-2016_100163335.html |website=Thaindian News |access-date=26 July 2009 |archive-date=5 October 2018 |archive-url=https://web.archive.org/web/20181005142406/http://www.thaindian.com/newsportal/health/nasa-orbiter-to-hunt-for-source-of-martian-methane-in-2016_100163335.html |url-status=dead }}</ref> as well as its decomposition products such as [[formaldehyde]] and [[methanol]].

=== Origins ===
ExoMars Trace Gas Orbiter was born out of the nexus of ESA's [[Aurora programme]] [[ExoMars]] flagship and NASA's 2013 and 2016 Mars Science Orbiter (MSO) concepts.<ref name="smithtgm20090910">{{cite web |url=http://www.spacepolicyonline.com/pages/images/stories/PSDS%20Mars1%20Smith-TGM.pdf |title=Mars Trace Gas Mission: Science Rationale & Concept |series=Presentation to the NRC Decadal Survey Mars Panel |first=Michael |last=Smith |date=10 September 2009 |access-date=9 November 2009 |archive-date=21 December 2010 |archive-url=https://web.archive.org/web/20101221094000/http://spacepolicyonline.com/pages/images/stories/PSDS%20Mars1%20Smith-TGM.pdf |url-status=dead }}</ref><ref name="JointInstrument">{{cite web |url=http://mepag.jpl.nasa.gov/meeting/jul-09/JIDT_for_MEPAG.pdf |title=Report to MEPAG on the ESA-NASA Joint Instrument Definition Team (JIDT) for the Proposed 2016 Orbiter-Carrier |publisher=NASA |first1=R. |last1=Zurek |first2=A. |last2=Chicarro |date=29 July 2009 |archive-url=https://web.archive.org/web/20090730203811/http://mepag.jpl.nasa.gov/meeting/jul-09/JIDT_for_MEPAG.pdf |archive-date=30 July 2009 |url-status=dead |df=dmy}}</ref> It became a flexible collaborative proposal within NASA and ESA to send a new orbiter-carrier to Mars in 2016 as part of the European-led ExoMars mission.<ref name="Mustard" /> On the ExoMars side, ESA authorised about half a billion Euros in 2005 for a rover and mini-station; eventually this evolved into being delivered by an orbiter rather than a cruise stage.<ref>{{cite web |url=http://spaceflight101.com/exomars/project-history/ |title=Brief ExoMars Project History |website=Spaceflight101.com |date=2016 |access-date=12 November 2016 |archive-date= 1 June 2017 |archive-url=https://web.archive.org/web/20170601003603/https://spaceflight101.com/exomars/project-history/}}</ref>

=== Attempted collaboration with NASA ===
[[NASA]]'s Mars Science Orbiter (MSO) was originally envisioned in 2008 as an all-NASA endeavour aiming for a late 2013 launch.<ref name="smithtgm20090910" /><ref name="JointInstrument" /> NASA and ESA officials agreed to pool resources and technical expertise and collaborate to launch only one orbiter.<ref name="split">{{Cite news |first=Michael A. |last=Taverna |title=ESA Proposes Two ExoMars Missions |date=19 October 2009 |website=[[Aviation Week]] |url=http://www.aviationweek.com/aw/generic/story_channel.jsp?channel=space&id=news%2FExomars101909.xml&headline=ESA%20Proposes%20Two%20ExoMars%20Missions |access-date=30 October 2009 |archive-date=14 November 2011 |archive-url=https://web.archive.org/web/20111114093557/http://www.aviationweek.com/aw/generic/story_channel.jsp?channel=space&id=news%2FExomars101909.xml&headline=ESA%20Proposes%20Two%20ExoMars%20Missions |url-status=dead }}</ref> The agreement, called the [[Mars Exploration Joint Initiative]], was signed in July 2009 and proposed to use an [[Atlas rocket]] launcher instead of a [[Soyuz (rocket family)|Soyuz rocket]], which significantly altered the technical and financial setting of the European ExoMars mission. 

Since the rover was originally planned to be launched along with the TGO, a prospective agreement would require that the rover lose enough weight to fit aboard the Atlas launch vehicle with NASA's orbiter.<ref name="space20090623">{{cite news |last1=Choi |first1=Charles Q. |title=NASA Poised to Join Europe's Mars Rover Mission |url=https://www.space.com/6881-nasa-poised-join-europe-mars-rover-mission.html |access-date=8 March 2023 |work=Space.com |date=23 June 2009 |archive-url=https://web.archive.org/web/20220818015604/https://www.space.com/6881-nasa-poised-join-europe-mars-rover-mission.html |archive-date=18 August 2022 |url-status=live }}</ref> Instead of reducing the rover's mass, it was nearly doubled when the mission was combined with other projects to a multi-spacecraft programme divided over two [[Atlas V]] launches:<ref name="split" /><ref name="oct12">{{Cite news |first=Jonathan |last=Amos |title=Europe's Mars plans move forward |date=12 October 2009 |url=http://news.bbc.co.uk/2/hi/science/nature/8302876.stm |work=BBC News |access-date=12 October 2009}}</ref> the ExoMars Trace Gas Orbiter (TGO) was merged into the project, carrying a meteorological lander planned for launch in 2016. The European orbiter would carry several instruments originally meant for NASA's MSO, so NASA scaled down the objectives and focused on atmospheric trace gases detection instruments for their incorporation in ESA's ExoMars Trace Gas Orbiter.<ref name="trace-gas-orbiter" /><ref name="Mustard" /><ref name="JointInstrument" />

Under the [[2013 United States federal budget|FY2013 budget]] President [[Barack Obama]] released on 13 February 2012, NASA terminated its participation in ExoMars due to budgetary cuts in order to pay for the cost overruns of the [[James Webb Space Telescope]].<ref>{{cite news |first=Ken |last=Kremr |title=Experts React to Obama Slash to NASA's Mars and Planetary Science Exploration |date=1 February 2012 |url=http://www.universetoday.com/93512/experts-react-to-obama-slash-to-nasas-mars-and-planetary-science-exploration/ |website=Universe Today |access-date=18 February 2012}}</ref> With NASA's funding for this project cancelled, most of ExoMars' plans had to be restructured.<ref name="cancellation">{{cite news |first=Megan |last=Whewell |title=Have Europe's Martian exploration plans been derailed by America? |date=15 February 2012 |website=MSN News |url=http://news.uk.msn.com/blog/the-space-blog-blogpost.aspx?post=1fac64fc-9e63-4c9c-9304-ce598c2ab71d |access-date=15 February 2012 |archive-url=https://web.archive.org/web/20120511105820/http://news.uk.msn.com/blog/the-space-blog-blogpost.aspx?post=1fac64fc-9e63-4c9c-9304-ce598c2ab71d |archive-date=11 May 2012 |url-status=dead }}</ref>

=== Collaboration with Russia ===
On 15 March 2012, the ESA's ruling council announced it would press ahead with its ExoMars program in partnership with the Russian space agency [[Roscosmos]], which planned to contribute two heavy-lift [[Proton (rocket family)|Proton launch vehicles]] and an additional entry, descent and landing system to the 2020 rover mission.<ref name="Svitak">{{cite news |first=Amy |last=Svitak |title=Europe Joins Russia on Robotic ExoMars |date=16 March 2012 |url=http://www.aviationweek.com/aw/generic/story_channel.jsp?channel=space&id=news/awx/2012/03/15/awx_03_15_2012_p0-437120.xml&headline=Europe%20Joins%20Russia%20on%20Robotic%20ExoMars |website=Aviation Week |access-date=16 March 2012 }}{{Dead link|date=August 2023 |bot=InternetArchiveBot |fix-attempted=yes }}</ref><ref name="bbc20120315">{{cite news |last1=Amos |first1=Jonathan |title=Europe still keen on Mars missions |url=https://www.bbc.com/news/science-environment-17390576 |access-date=8 March 2023 |work=BBC News |date=15 March 2012 |archive-url=https://web.archive.org/web/20221107174842/https://www.bbc.com/news/science-environment-17390576 |archive-date=7 November 2022 |url-status=live }}</ref><ref>{{cite news |title=NASA drops ExoMars missions in 2013 budget |date=15 February 2012 |url=http://optics.org/news/3/2/23 |work=Optics |access-date=15 February 2012}}</ref><ref>{{cite news |website=The Guardian |url=https://www.theguardian.com/science/2012/mar/16/spacewatch-nasa-mars-exomars |title=Spacewatch: Uncertainties for ExoMars |date=16 March 2012}}</ref><ref name="stillKeen">{{cite news |first=Jonathan |last=Amos |title=Europe still keen on Mars missions |date=15 March 2012 |url=https://www.bbc.co.uk/news/science-environment-17390576 |website=BBC News |access-date=16 March 2012}}</ref>

Under the collaboration proposal with Roscosmos, the ExoMars mission was split into two parts: the orbiter/lander mission in March 2016 that includes the TGO and a {{convert|2.4|m|ftin|abbr=on}} diameter stationary lander built by ESA named [[Schiaparelli EDM lander|''Schiaparelli'']],<ref name="ExoMars">{{cite web |url=http://www.russianspaceweb.com/exomars_2016.html |title=ExoMars |access-date=22 October 2013 |work=Russian Space Web}}</ref> and the [[Rosalind Franklin (rover)|''Rosalind Franklin'' rover]] mission in 2020.<ref name="LaunchMoved2020">{{cite press release |title=Second ExoMars mission moves to next launch opportunity in 2020 |date=2 May 2016 |publisher=[[European Space Agency]] |url=http://www.esa.int/For_Media/Press_Releases/Second_ExoMars_mission_moves_to_next_launch_opportunity_in_2020 |access-date=2 May 2016}}</ref> Both missions were expected to use a [[Proton-M]] rocket. The [[Rosalind Franklin (rover)|''Rosalind Franklin'' rover]] mission was later postponed<ref name="LaunchMoved2022">{{cite press release |title=N° 6–2020: ExoMars to take off for the Red Planet in 2022 |date=12 March 2020 |publisher=[[ESA]] |url=http://www.esa.int/Newsroom/Press_Releases/ExoMars_to_take_off_for_the_Red_Planet_in_2022 |access-date=12 March 2020}}</ref> and in 2022, after [[Russian invasion of Ukraine]], ESA terminated its cooperation on the project with Russia.<ref>{{Cite web |author1=Mike Wall |date=2022-07-13 |title=Europe ending cooperation with Russia on life-hunting Mars rover |url=https://www.space.com/europe-ends-cooperation-russia-exomars-rover |access-date=2025-06-01 |website=Space |language=en}}</ref>

=== Launch ===
The Trace Gas Orbiter and descent module ''Schiaparelli'' completed testing and were integrated to a Proton rocket at the [[Baikonur Cosmodrome]] in Kazakhstan in mid-January 2016.<ref>{{cite news |url=https://spaceref.com/science-and-exploration/exomars-2016-schiaparelli-module-in-baikonur/ |title=ExoMars 2016 ''Schiaparelli'' Module in Baikonur |work=ESA |publisher=SpaceRef |date=5 January 2016 |access-date=3 December 2024}}</ref> The launch occurred at 09:31&nbsp;[[UTC]] on 14 March 2016.<ref name="bbcnews20160314">{{cite news |url=https://www.bbc.co.uk/news/science-environment-35799792 |title=Mars methane mission lifts off |first=Jonathan |last=Amos |publisher=BBC |date=14 March 2016 |access-date=14 March 2016}}</ref> Four rocket burns occurred in the following 10 hours before the descent module and orbiter were released.<ref name=Gibney_Nature_11_March_2016>{{cite journal |title=Mars launch to test collaboration between Europe and Russia |journal=[[Nature (journal)|Nature]] |date=11 March 2016 |first=Elizabeth |last=Gibney |doi=10.1038/nature.2016.19547 |volume=531 |issue=7594 |pages=288–299 |pmid=26983519 |bibcode=2016Natur.531..288G|doi-access=free }}</ref> A signal from the spacecraft was received at 21:29&nbsp;UTC that day, confirming that the launch was successful and the spacecraft were functioning properly.<ref>{{cite news |url=http://www.esa.int/Our_Activities/Space_Science/ExoMars/ExoMars_on_its_way_to_solve_the_Red_Planet_s_mysteries |title=ExoMars on its way to solve the Red Planet's mysteries |publisher=ESA |date=14 March 2016 |access-date=15 March 2016 |archive-url=https://web.archive.org/web/20161026085720/http://www.esa.int/Our_Activities/Space_Science/ExoMars/ExoMars_on_its_way_to_solve_the_Red_Planet_s_mysteries |archive-date=26 October 2016 |url-status=dead }}</ref>

Shortly after separation from the probes, a Brazilian ground telescope recorded small objects in the vicinity of the [[Briz (rocket stage)|Briz-M]] upper booster stage, suggesting that the Briz-M stage exploded a few kilometres away, without damaging the orbiter or lander.<ref name="exploded booster">{{cite news |last=King |first=Bob |url=http://www.universetoday.com/128073/exomars-mission-narrowly-avoids-exploding-booster/ |title=ExoMars Mission Narrowly Avoids Exploding Booster |work=Universe Today |date=24 March 2016 |access-date=25 March 2016}}</ref> Briefing reporters in Moscow, the head of Roscosmos denied any anomaly and made all launch data available for inspection.<ref>{{cite news |last=de Selding |first=Peter B. |url=http://spacenews.com/roscosmos-gives-detailed-rebuttal-to-reports-of-proton-upper-stage-anomaly-after-exomars-separation/ |title=Roscosmos gives detailed rebuttal to reports of Proton ExoMars launch anomaly |work=Space News |date=5 April 2016 |access-date=5 April 2016}}</ref>

=== At Mars ===
The [[Schiaparelli EDM lander|''Schiaparelli'']] lander separated from the TGO orbiter on 16 October 2016,<ref name="separation">{{cite news |last=Malik |first=Tariq |url=http://www.space.com/34399-european-mars-lander-separates-exomars-mothership.html |title=European Mars Lander Separates From Mothership, Takes Aim at Red Planet |work=Space.com |date=16 October 2016 |access-date=16 October 2016}}</ref> three days before it arrived on Mars, and entered the atmosphere at {{convert|21000|km/h|mph km/s|abbr=on}}.<ref name='NewSci March'>{{cite news |last=Aron |first=Jacob |url=https://www.newscientist.com/article/2079697-exomars-probe-set-to-sniff-out-signs-of-life-on-the-red-planet/ |title=ExoMars probe set to sniff out signs of life on the Red Planet |work=New Scientist |date=7 March 2016 |access-date=7 March 2016}}</ref> ''Schiaparelli'' transmitted about 600 megabytes of telemetry during its landing attempt,<ref name="Selding2">{{cite news |url=http://spacenews.com/europes-exomars-successfully-inserted-into-mars-orbit-but-lander-may-be-lost/ |title=Europe's ExoMars enters Mars orbit, but lander feared lost |work=[[SpaceNews]] |first=Peter B. |last=de Selding |date=20 October 2016 |access-date=21 October 2016}}</ref><ref name="nsf20161019">{{cite news |last1=Gebhardt |first1=Chris |title=ExoMars completes crucial orbit insertion, hope lost for lander |url=https://www.nasaspaceflight.com/2016/10/exomars-duo-orbit-insertion-landing-mars/ |access-date=8 March 2023 |work=NASASpaceflight.com |date=19 October 2016 |archive-url=https://web.archive.org/web/20221025222820/https://www.nasaspaceflight.com/2016/10/exomars-duo-orbit-insertion-landing-mars/ |archive-date=25 October 2022 |url-status=live }}</ref> before it impacted the surface at {{convert|540|km/h|mph|abbr=on}}.<ref name="guardian20161124">{{cite news |url=https://www.theguardian.com/science/2016/nov/24/mars-lander-smashed-into-ground-at-540kmh-after-misjudging-its-altitude |title=Mars lander smashed into ground at 540km/h after misjudging its altitude |work=The Guardian |agency=Agence France-Presse |date=24 November 2016 |access-date=1 January 2017}}</ref>

The TGO was injected into Mars orbit on 19 October 2016 and underwent 11 months of [[aerobraking]] (March 2017 to February 2018), reducing its orbital speed by {{convert|3600|km/h|mph|abbr=on}} and its orbit from an initial {{convert|98000|by|200|km|mi|abbr=on}} down to {{convert|1050|by|200|km|mi|abbr=on}}. Additional thruster firings through mid-April circularised the spacecraft's orbit to {{convert|400|km|mi|abbr=on}}, and full science activities began on 21 April 2018.<ref name="space20180223">{{cite news |url=https://www.space.com/39796-methane-sniffing-mars-orbiter-aerobraking-dives.html |title=Methane-Sniffing Orbiter Finishes 'Aerobraking' Dives Through Mars' Atmosphere |work=Space.com |first=Mike |last=Wall |date=23 February 2018 |access-date=24 February 2018}}</ref><ref>{{cite conference |title=ExoMars Trace Gas Orbiter provides atmospheric data during Aerobraking into its final orbit |conference=49th Annual Division for Planetary Sciences Meeting. 15–20 October 2017. Provo, Utah. |first1=Hakan |last1=Svedhem |first2=Jorge L. |last2=Vago |first3=Sean |last3=Bruinsma |first4=Ingo |last4=Müller-Wodarg |display-authors=etal |date=2017 |bibcode=2017DPS....4941801S |id=418.01}}</ref>

=== Results ===
[[File:Layered_deposits_at_the_south_pole_of_Mars_ESA394865.jpg|thumb|Image of the edge of [[Planum Australe]], Mars' south polar ice cap, taken by CaSSIS. The dusty ice layers that compose the South Polar Layered Deposits (SPLD) are exposed and visible in the image. ]]

The spacecraft took its first photos of the surface of Mars on 15 April 2018.<ref name="esa20180426">{{cite web |last1=Thomas |first1=Nicolas |last2=Svedhem |first2=Håkan |last3=Bauer |first3=Markus |display-authors=1 |date=26 April 2018 |title=ExoMars returns first images from new orbit |url=https://www.esa.int/Our_Activities/Space_Science/ExoMars/ExoMars_returns_first_images_from_new_orbit |archive-url=https://web.archive.org/web/20180427232605/https://www.esa.int/Our_Activities/Space_Science/ExoMars/ExoMars_returns_first_images_from_new_orbit |archive-date=27 April 2018 |access-date=18 June 2018 |publisher=European Space Agency}}</ref> The first year of science operations<ref>{{Cite journal |last1=Svedhem |first1=H. |last2=Vago |first2=J. L. |last3=Rodionov |first3=D. |date=2019-12-01 |title=The ExoMars Trace Gas Orbiter - New Results and Future Plans |url=http://adsabs.harvard.edu/abs/2019AGUFM.P23B3482S |journal=AGU Fall Meeting Abstracts |volume=23 |bibcode=2019AGUFM.P23B3482S}}</ref> yielded a wealth of new data and scientific discoveries, including: new observations of the atmospheric composition and structure,<ref>{{Cite journal |last1=Trokhimovskiy |first1=A. |last2=Perevalov |first2=V. |last3=Korablev |first3=O. |last4=Fedorova |first4=A. A. |last5=Olsen |first5=K. S. |last6=Bertaux |first6=J.-L. |last7=Patrakeev |first7=A. |last8=Shakun |first8=A. |last9=Montmessin |first9=F. |last10=Lefèvre |first10=F. |last11=Lukashevskaya |first11=A. |date=2020-07-01 |title=First observation of the magnetic dipole CO2 absorption band at 3.3 μm in the atmosphere of Mars by the ExoMars Trace Gas Orbiter ACS instrument |url=https://www.aanda.org/articles/aa/abs/2020/07/aa38134-20/aa38134-20.html |journal=Astronomy & Astrophysics |language=en |volume=639 |pages=A142 |bibcode=2020A&A...639A.142T |doi=10.1051/0004-6361/202038134 |issn=0004-6361 |doi-access=free}}</ref><ref>{{Cite journal |last1=Olsen |first1=K. S. |last2=Lefèvre |first2=F. |last3=Montmessin |first3=F. |last4=Fedorova |first4=A. A. |last5=Trokhimovskiy |first5=A. |last6=Baggio |first6=L. |last7=Korablev |first7=O. |last8=Alday |first8=J. |last9=Wilson |first9=C. F. |last10=Forget |first10=F. |last11=Belyaev |first11=D. A. |date=2021-01-18 |title=The vertical structure of CO in the Martian atmosphere from the ExoMars Trace Gas Orbiter |journal=Nature Geoscience |language=en |volume=14 |issue=2 |pages=67–71 |bibcode=2021NatGe..14...67O |doi=10.1038/s41561-020-00678-w |issn=1752-0908 |doi-access=free}}</ref> water-ice cloud enhancement during a global dust storm,<ref>{{Cite journal |last1=Stcherbinine |first1=A. |last2=Vincendon |first2=M. |last3=Montmessin |first3=F. |last4=Wolff |first4=M. J. |last5=Korablev |first5=O. |last6=Fedorova |first6=A. |last7=Trokhimovskiy |first7=A. |last8=Patrakeev |first8=A. |last9=Lacombe |first9=G. |last10=Baggio |first10=L. |last11=Shakun |first11=A. |date=2020 |title=Martian Water Ice Clouds During the 2018 Global Dust Storm as Observed by the ACS-MIR Channel Onboard the Trace Gas Orbiter |url=https://agupubs.pericles-prod.literatumonline.com/doi/abs/10.1029/2019JE006300 |journal=Journal of Geophysical Research: Planets |language=en |volume=125 |issue=3 |pages=e2019JE006300 |arxiv=1912.08018 |bibcode=2020JGRE..12506300S |doi=10.1029/2019JE006300 |issn=2169-9100 |s2cid=209386623}}</ref> new measurements of the atmospheric thermal structure and density,<ref>{{Cite journal |last1=Siddle |first1=A. G. |last2=Mueller-Wodarg |first2=I. C. F. |last3=Bruinsma |first3=S. |last4=Marty |first4=J. -C. |date=2020-10-23 |title=Density structures in the martian lower thermosphere as inferred by Trace Gas Orbiter accelerometer measurements |url=http://www.sciencedirect.com/science/article/pii/S0019103520304541 |journal=Icarus |language=en |volume=357 |pages=114109 |doi=10.1016/j.icarus.2020.114109 |issn=0019-1035 |s2cid=226339347 |url-access=subscription}}</ref> estimations of the timespan of the climate record of the south polar ice sheet,<ref>{{Cite journal |last1=Becerra |first1=Patricio |last2=Sori |first2=Michael M. |last3=Thomas |first3=Nicolas |last4=Pommerol |first4=Antoine |last5=Simioni |first5=Emanuele |last6=Sutton |first6=Sarah S. |last7=Tulyakov |first7=Stepan |last8=Cremonese |first8=Gabriele |date=2019 |title=Timescales of the Climate Record in the South Polar Ice Cap of Mars |url=https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1029/2019GL083588 |journal=Geophysical Research Letters |language=en |volume=46 |issue=13 |pages=7268–7277 |bibcode=2019GeoRL..46.7268B |doi=10.1029/2019GL083588 |issn=1944-8007 |s2cid=198424636 |hdl-access=free |hdl=10150/634664}}</ref> confirmation of dry-processes being responsible for [[Recurring slope lineae|Recurring Slope Lineae]] in Hale crater,<ref>{{Cite journal |last1=Munaretto |first1=G. |last2=Pajola |first2=M. |last3=Cremonese |first3=G. |last4=Re |first4=C. |last5=Lucchetti |first5=A. |last6=Simioni |first6=E. |last7=McEwen |first7=A. S. |last8=Pommerol |first8=A. |last9=Becerra |first9=P. |last10=Conway |first10=S. J. |last11=Thomas |first11=N. |date=2020-08-01 |title=Implications for the origin and evolution of Martian Recurring Slope Lineae at Hale crater from CaSSIS observations |url=http://www.sciencedirect.com/science/article/pii/S0032063320300660 |journal=Planetary and Space Science |language=en |volume=187 |pages=104947 |bibcode=2020P&SS..18704947M |doi=10.1016/j.pss.2020.104947 |issn=0032-0633 |s2cid=218929279|hdl=11577/3341444 |hdl-access=free }}</ref> identifying a variety of ice and non-ice related active processes occurring on the surface in colour,<ref>{{Cite journal |last1=Rangarajan |first1=Vidhya Ganesh |last2=Tornabene |first2=Livio L. |last3=Osinski |first3=Gordon R. |last4=Conway |first4=Susan J. |last5=Seelos |first5=Frank P. |last6=Silvestro |first6=Simone |last7=Salese |first7=Francesco |last8=Pajola |first8=Maurizio |last9=Lucchetti |first9=Alice |last10=Munaretto |first10=Giovanni |last11=Bickel |first11=Valentin T. |last12=Thomas |first12=Nicolas |last13=Cremonese |first13=Gabriele |date=2023-04-01 |title=Change detection and monitoring of active Martian surface phenomena with the Colour and Stereo Surface Imaging System (CaSSIS) onboard the ExoMars Trace Gas Orbiter (TGO) |url=https://linkinghub.elsevier.com/retrieve/pii/S0019103523000209 |journal=Icarus |volume=394 |pages=115443 |bibcode=2023Icar..39415443R |doi=10.1016/j.icarus.2023.115443 |issn=0019-1035}}</ref> and high-resolution maps of shallow subsurface Hydrogen, increasing the known amounts of probably near-surface buried water ice.<ref>{{Cite journal |last1=Malakhov |first1=Alexey |last2=Mitrofanov |first2=Igor |last3=Golovin |first3=Dmitry |last4=Sanin |first4=Anton |last5=Litvak |first5=Maxim |last6=Mokrousov |first6=Maxim |last7=Kozyrev |first7=Alexander |last8=Tretyakov |first8=Vladislav |last9=Djachkova |first9=Maya |last10=Nikiforov |first10=Sergey |last11=Lisov |first11=Denis |date=2019-04-01 |title=Mars subsurface hydrogen as seen by FREND onboard TGO |url=http://adsabs.harvard.edu/abs/2019EGUGA..2116504M |journal=EGU General Assembly Conference Abstracts |volume=21 |pages=16504 |bibcode=2019EGUGA..2116504M}}</ref>

In April 2019, the science team reported their first methane results: TGO had detected no methane whatsoever, even though their data were more sensitive than the methane concentrations found using ''[[Curiosity (rover)|Curiosity]]'', ''[[Mars Express]]'', and ground-based observations.<ref>{{cite journal |last1=Korablev |first1=Oleg |last2=Vandaele |first2=Ann Carine |last3=Montmessin |first3=Franck |last4=Fedorova |first4=Anna A. |last5=Trokhimovskiy |first5=Alexander |last6=Forget |first6=François |last7=Lefèvre |first7=Franck |last8=Daerden |first8=Frank |last9=Thomas |first9=Ian . |last10=Trompet |first10=Loïc |last11=Erwin |first11=Justin T. |last12=Aoki |first12=Shohei |last13=Robert |first13=Séverine |last14=Neary |first14=Lori |last15=Viscardy |first15=Sébastien |display-authors=1 |year=2019 |title=No detection of methane on Mars from early ExoMars Trace Gas Orbiter observations |url=http://oro.open.ac.uk/60547/2/2019%20Korablev%20TGO%20methane%20Nature_accepted.pdf |journal=Nature |volume=568 |issue=7753 |pages=517–520 |bibcode=2019Natur.568..517K |doi=10.1038/s41586-019-1096-4 |pmid=30971829 |s2cid=106411228 |last16=Grigoriev |first16=Alexey . |last17=Ignatiev |first17=Nikolay I. |last18=Shakun |first18=Alexey |last19=Patrakeev |first19=Andrey |last20=Belyaev |first20=Denis A. |last21=Bertaux |first21=Jean-Loup |last22=Olsen |first22=Kevin S. |last23=Baggio |first23=Lucio |last24=Alday |first24=Juan |last25=Ivanov |first25=Yuriy S. |last26=Ristic |first26=Bojan |last27=Mason |first27=Jon |last28=Willame |first28=Yannick |last29=Depiesse |first29=Cédric |last30=Hetey |first30=Laszlo|hdl=10261/190885 }}</ref><ref>{{cite journal |last1=Trokhimovskiy |first1=A. |last2=Perevalov |first2=V. |last3=Korablev |first3=O. |last4=Fedorova |first4=A. A. |last5=Olsen |first5=K. S. |last6=Bertaux |first6=J.-L. |last7=Patrakeev |first7=A. |last8=Shakun |first8=A. |last9=Montmessin |first9=F. |last10=Lefèvre |first10=F. |last11=Lukashevskaya |first11=A. |year=2020 |title=First observation of the magnetic dipole CO2absorption band at 3.3μm in the atmosphere of Mars by the Exo ''Mars'' Trace Gas Orbiter ACS instrument |url=https://www.aanda.org/articles/aa/abs/2020/07/aa38134-20/aa38134-20.html |journal=Astronomy & Astrophysics |volume=639 |pages=A142 |bibcode=2020A&A...639A.142T |doi=10.1051/0004-6361/202038134 |s2cid=225600219 |doi-access=free}}</ref> As of 2021, still no methane was detected and scientists used the TGO measurements to set new upper limit on its possible concentration in the atmosphere of Mars (less than 0.05 [[ppbv]] and likely less than 0.02 ppbv). Also, no localised plumes of methane were detected.<ref>{{Cite web |last= |first= |date=2021-07-22 |title=ESA's ExoMars Orbiter Detects No Methane in Martian Atmosphere {{!}} Planetary Science {{!}} Sci-News.com |url=https://www.sci.news/space/exomars-no-methane-martian-atmosphere-09888.html |access-date=2025-06-01 |website=Sci.News: Breaking Science News |language=en-US}}</ref>

In 2020, scientists reported the first detection of green oxygen [[airglow]] in Mars' atmosphere. For this they used the TGO's NOMAD instrument pointing at the edge of Mars, similarly to analogous observations of Earth airglow from the [[International Space Station|ISS]].<ref>{{Cite web |title=ExoMars spots unique green glow at the Red Planet |url=https://www.esa.int/About_Us/ESAC/ExoMars_spots_unique_green_glow_at_the_Red_Planet |access-date=2025-06-01 |website=www.esa.int |language=en}}</ref><ref>{{Cite journal |last1=Gérard |first1=J.-C. |last2=Aoki |first2=S. |last3=Willame |first3=Y. |last4=Gkouvelis |first4=L. |last5=Depiesse |first5=C. |last6=Thomas |first6=I. R. |last7=Ristic |first7=B. |last8=Vandaele |first8=A. C. |last9=Daerden |first9=F. |last10=Hubert |first10=B. |last11=Mason |first11=J. |last12=Patel |first12=M. R. |last13=López-Moreno |first13=J.-J. |last14=Bellucci |first14=G. |last15=López-Valverde |first15=M. A. |date=2020 |title=Detection of green line emission in the dayside atmosphere of Mars from NOMAD-TGO observations |url=https://www.nature.com/articles/s41550-020-1123-2 |journal=Nature Astronomy |language=en |volume=4 |issue=11 |pages=1049–1052 |doi=10.1038/s41550-020-1123-2 |bibcode=2020NatAs...4.1049G |issn=2397-3366}}</ref>

Since 2020, TGO has been cooperating with ''[[Mars Express]]'' on mutual [[radio occultation]] experiments measuring the physical properties of Mars atmosphere. A publication of a study in 2024 in ''[[Radio Science]]'' marked the first routine use of this technique at another planet<ref>{{Cite journal |last1=Parrott |first1=Jacob |last2=Svedhem |first2=Håkan |last3=Witasse |first3=Olivier |last4=Wilson |first4=Colin |last5=Müller-Wodarg |first5=Ingo |last6=Cardesín-Moinelo |first6=Alejandro |last7=Schmitz |first7=Peter |last8=Godfrey |first8=James |last9=Reboud |first9=Olivier |last10=Geiger |first10=Bernhard |last11=Sánchez-Cano |first11=Beatriz |last12=Nava |first12=Bruno |last13=Migoya-Orué |first13=Yenca |date=2024 |title=First Results of Mars Express—ExoMars Trace Gas Orbiter Mutual Radio Occultation |url=https://onlinelibrary.wiley.com/doi/abs/10.1029/2023RS007873 |journal=Radio Science |language=en |volume=59 |issue=7 |pages=e2023RS007873 |doi=10.1029/2023RS007873 |issn=1944-799X|hdl=10261/371076 |hdl-access=free }}</ref><ref>{{Cite web |last1=Dunning |first1=Hayley |last2=London |first2=Imperial College |title=Repurposed technology used to probe new regions of Mars' atmosphere |url=https://phys.org/news/2024-07-repurposed-technology-probe-regions-mars.html |access-date=2025-06-22 |website=phys.org |language=en}}</ref> and in June 2025, a comprehensive data set from these observations has been made publicly available.<ref>{{Cite web |last=Stanley |first=Sarah |date=2025-06-20 |title=Orbiter Pair Expands View of Martian Ionosphere |url=https://eos.org/research-spotlights/orbiter-pair-expands-view-of-martian-ionosphere |access-date=2025-06-21 |website=Eos |language=en-US}}</ref><ref>{{Cite journal |last1=Parrott |first1=Jacob |last2=Svedhem |first2=Håkan |last3=Sánchez-Cano |first3=Beatriz |last4=Witasse |first4=Olivier |last5=Wilson |first5=Colin |last6=Müller-Wodarg |first6=Ingo |date=2025 |title=Ionospheric Analysis With Martian Mutual Radio Occultation |journal=Journal of Geophysical Research: Planets |language=en |volume=130 |issue=6 |doi=10.1029/2024JE008854 |issn=2169-9097|doi-access=free |bibcode=2025JGRE..13008854P }}</ref>

== See also ==
{{Portal|Astronomy|Biology|Solar System|Spaceflight}}
* [[List of European Space Agency programmes and missions]]
* {{annotated link|Curiosity (rover)}}
* {{annotated link|List of missions to Mars}}
* {{annotated link|Mars 2020}}
* {{annotated link|Mars Exploration Joint Initiative}}
* {{annotated link|Mars Express}}
* {{annotated link|Mars Global Surveyor}}
* {{annotated link|Mars Orbiter Mission}}
* {{annotated link|MAVEN}}
* {{annotated link|Natural methane on Mars}}
== References ==
{{reflist|colwidth=30em}}

== External links ==
* [http://exploration.esa.int/jump.cfm?oid=46475 ExoMars Trace Gas Orbiter] at ESA.int
* [https://www.esa.int/Science_Exploration/Human_and_Robotic_Exploration/Exploration/ExoMars/Trace_Gas_Orbiter_instruments Trace Gas Orbiter instruments] at ESA.int
* [https://www.esa.int/Science_Exploration/Human_and_Robotic_Exploration/Exploration/ExoMars/(archive)/0 ExoMars Archive] at ESA.int
* [https://www.flickr.com/photos/europeanspaceagency/albums/72157651339630276 ESA ExoMars] on Flickr

{{Exomars}}
{{European Space Agency}}
{{Russian space program}}
{{Astrobiology}}
{{Mars spacecraft}}
{{Solar System probes}}
{{2016 in space}}
{{Orbital launches in 2016}}

{{Use dmy dates|date=November 2016}}
{{Use British English|date=October 2016}}

[[Category:ExoMars]]
[[Category:European Space Agency space probes]]
[[Category:Russian space probes]]
[[Category:Satellites orbiting Mars]]
[[Category:Attached spacecraft]]
[[Category:Space probes launched in 2016]]
[[Category:Roscosmos]]