ExoMars Trace Gas Orbiter

ExoMars Trace Gas Orbiter
Name	ExoMars Trace Gas Orbiter
Mission type	Mars orbiter, atmospheric chemistry
Operator	European Space Agency, Roscosmos
Launch date	2016-03-14
Launch vehicle	Proton-M/Briz-M
Launch site	Baikonur Cosmodrome
Orbit	400 km circular Martian orbit (nominal)
Instruments	ACS, NOMAD, FREND, CaSSIS, LaRa, DAN? (see text)

ExoMars Trace Gas Orbiter

The ExoMars Trace Gas Orbiter is a joint European Space Agency–Roscosmos robotic spacecraft studying the Martian atmosphere and trace gases with high spectral and spatial resolution, developed under the ExoMars programme and launched from Baikonur Cosmodrome on a Proton-M/Briz-M vehicle. The mission supports objectives set by agencies including European Space Agency, Roscosmos State Corporation, and scientific institutions such as the Institut d'Astrophysique Spatiale, Laboratoire Atmosphères, Milieux, Observations Spatiales, and Max Planck Institute for Solar System Research.

Overview and mission objectives

The primary objective is to detect and map trace gases, especially methane and other hydrocarbons, and to determine their spatial and temporal variability using spectrometers and remote sensing instruments, building on prior observations from missions like Mars Express, Mars Reconnaissance Orbiter, Curiosity and telescopic campaigns involving Hubble Space Telescope and Infrared Space Observatory. Secondary objectives include characterizing the Martian atmosphere and surface water-ice distribution, supporting future exploration efforts such as the ExoMars Rosalind Franklin rover and informing concepts from programs like Mars Sample Return and proposals from agencies including NASA and JAXA. The mission also served as a technology demonstrator for aerobraking and communications relay, linking to assets such as InSight and orbiters in the Mars exploration program.

Spacecraft design and instruments

The spacecraft bus was built by organizations including Thales Alenia Space, OHB System AG, and subcontractors tied to ESA and Roscosmos, integrating instruments provided by international teams from institutions such as the Institute of Atmospheric Sciences and Climate, Laboratoire Atmosphères, Observations, Géosciences, and NASA Jet Propulsion Laboratory. Key payloads include the Nadir and Occultation for Mars Discovery (NOMAD) spectrometer suite developed by Institut d'Astrophysique Spatiale and Belgian Institute for Space Aeronomy; the Atmospheric Chemistry Suite (ACS) led by Russian Academy of Sciences laboratories; the Colour and Stereo Surface Imaging System (CaSSIS) built by a consortium including University of Bern; the Fine-Resolution Epithermal Neutron Detector (FREND) provided by Space Research Institute (IKI) partners; and the radio-science LaRa experiment developed by teams from Centro de Astrobiología and Royal Observatory of Belgium. Subsystems include power from solar arrays designed by Astrium, communications compatible with Deep Space Network relay concepts, and propulsion systems using designs by Khrunichev State Research and Production Space Center.

Launch, cruise, and Mars insertion

Launched on 14 March 2016 from Baikonur Cosmodrome aboard a Proton-M rocket with a Briz-M upper stage, the spacecraft executed an interplanetary cruise trajectory supervised by flight dynamics teams from European Space Operations Centre and ROSCOSMOS Flight Control Center, performing trajectory correction maneuvers similar in procedure to those used by Mars Express and Mars Odyssey. Arrival operations included a complex aerobraking campaign and a precise Mars orbit insertion maneuver coordinated with mission control centers and supported by tracking from facilities such as Goldstone Deep Space Communications Complex and Moscow Deep Space Communications Complex. The spacecraft entered a long period of aerobraking to reach a low, circular science orbit over months, employing techniques comparable to those used by Mars Reconnaissance Orbiter aerobraking phases.

Science operations and results

Science operations are conducted from planning centers including European Space Astronomy Centre and instrument teams at institutions such as Max Planck Institute for Solar System Research, Royal Belgian Institute for Space Aeronomy, and IKI. Observations include solar occultation, nadir mapping, and limb sounding modes analogous to campaigns by Mars Express and MAVEN; these modes enabled high-sensitivity detections and cross-calibration with contemporaneous missions like Curiosity and Perseverance. The spacecraft also functions as a communications relay for surface assets, interoperating with missions from NASA, Roscosmos, and mission concepts under ExoMars programme planning.

Data analysis and discoveries

Data processing and analysis are performed by distributed teams at facilities including European Space Astronomy Centre, Institut de Planétologie et d'Astrophysique de Grenoble, and Space Research Institute (IKI), using pipelines informed by heritage from HITRAN spectral databases and calibration efforts tied to instruments on Mars Express and Rosetta. Key findings include refined upper limits and localized detections of methane variability, mapping of water-ice and hydrated minerals consistent with observations from Mars Reconnaissance Orbiter and ODYESSY? (see instrument literature), constraints on potential geochemical or biological sources linked to studies by Curiosity and laboratory work at institutions such as California Institute of Technology and Smithsonian Astrophysical Observatory. Remote neutron mapping by FREND improved models of subsurface hydrogen distribution building on datasets from Mars Odyssey.

Mission operations and collaboration

Mission operations represent a multinational collaboration among European Space Agency, Roscosmos State Corporation, contractors like Thales Alenia Space and Khrunichev State Research and Production Space Center, and scientific partners from universities and institutes including University of Oxford, Imperial College London, Institut d'Astrophysique de Paris, and Max Planck Institute for Solar System Research. The program exemplifies coordination in data sharing, joint operations, and contingency planning similar to arrangements used by International Space Station partners and interagency cooperation models involving NASA and JAXA.

Legacy and future implications

The mission’s legacy includes contributions to target selection and environmental characterization for the ExoMars Rosalind Franklin rover and future sample return architectures pursued by NASA and ESA, informing planetary protection policies guided by COSPAR and procedures used in Viking era studies. Scientific datasets archived at centers like European Space Astronomy Centre support ongoing research into Martian atmospheric chemistry, surface volatiles, and potential biosignatures, influencing future mission concepts proposed to agencies including ESA, Roscosmos, NASA, and CNES.

Category:ExoMars