The ExoMars Trace Gas Orbiter (ExoMars TGO) is searching for methane and other trace gases in the Martian atmosphere that could be evidence of possible biological or geological activity.

  • The orbiter is the first in a series of joint missions between the European Space Agency (ESA) and Roscosmos, the Russian space agency.
  • It’s also meant to test technology for future missions.
  • Exomars Trace Gas Orbiter began operations after entering Mars orbit on Oct. 19, 2016
  • The mission’s Schiaparelli lander crashed on the Martian surface due to conflicting information from an onboard computer.
Launch Date March 14, 2016 | 09:31 UT
Launch Site Baikonur Cosmodrome, Kazakhstan, Russia
Destination Mars
Type In Orbit
Status Primary Mission in Progress
Agencies European Space Agency, Roscosmos
Alternate Names Trace Gas Orbiter, 2016 Exomars, TGO, 2016-017A, 41388

Key Dates

March 14, 2016: Launch | 09:31 UT

Oct. 19, 2016: Mars Orbit Insertion

March 2018: Communications Relay Operations

March 2018 - December 2019: Primary Science Operations

In Depth

Objective(s): Mars orbiter, lander
Spacecraft Mass: 9,550 pounds (4,332 kg) total including 8,278 pounds (3,755 kg) TGO and 1,272 pounds (577 kg) Schiaparelli EDM
Scientific Instruments:

  1. Nadir and Occultation for Mars Discovery spectrometer (NOMAD)
  2. Atmospheric Chemistry Suite spectrometers (ACS)
  3. Color and Stereo Surface Imaging System (CaSSIS)
  4. Fine-Resolution Epithermal Neutron Detector (FREND)

The ExoMars Trace Gas Orbiter (TGO) was designed to search for trace gases in the Martian atmosphere such as methane, water vapor, nitrogen oxides and acetylene. These gases could provide evidence for possible biological or geological activity on Mars. Organisms on Earth release methane during digestion, although geological processes such as the oxidation of minerals can also release methane.

ExoMars also will monitor seasonal changes in the Martian atmosphere and will look for water-ice beneath the surface. Information gathered during the mission will help decide landing sites for future ESA missions.

A second mission, ExoMars 2020, is planned for launch in 2020 and will include a rover capable of drilling about 6 feet (two meters) below the surface to search of clues for past life on Mars. ExoMars TGO will support the mission by relaying data from the rover to mission managers.

A 3D model of ESA's Trace Gas Orbiter (TGO) mission. Credit: NASA Visualization Technology Applications and Development (VTAD) › Download Options

Additional Resources


Siddiqi, Asif A. Beyond Earth: A Chronicle of Deep Space Exploration, 1958-2016. NASA History Program Office, 2018.

Schiaparelli landing investigation completed (May 24, 2017):

ExoMars mission team:

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