On October 19, 2026, the European Space Agency (ESA) reported that past and present ExoMars team members had gathered at its European Space Operations Centre (ESOC) in Darmstadt to mark ten years since the ExoMars Trace Gas Orbiter (TGO) reached Mars. The anniversary looked back at a spacecraft whose work spans atmospheric science and communications support for surface missions.
TGO’s arrival at Mars
TGO arrived at Mars on October 19, 2016, at 15:24 UTC, according to ESA. Its Mars Orbit Insertion engine burn had begun at 13:05 UTC. The spacecraft passed behind Mars during the burn, then reappeared and sent telemetry that allowed flight controllers to confirm it had entered orbit.
The arrival began a long adjustment to TGO’s orbit. ESA says the spacecraft spent almost a year aerobraking, using drag from the Martian atmosphere to slow down. EXOPLANETAS Noticias Ciencia y Tecnología reported that aerobraking ended on February 20, 2018.
| Date | Event |
| October 19, 2016, 13:05 UTC | TGO began its Mars Orbit Insertion engine burn. |
| October 19, 2016, 15:24 UTC | TGO reached Mars and was confirmed in orbit. |
| February 20, 2018 | TGO completed aerobraking, according to EXOPLANETAS Noticias Ciencia y Tecnología. |
| October 19, 2026 | ESA reported an anniversary gathering at ESOC, ten years after TGO’s arrival. |
The Mars science ESA highlights
ESA says TGO studies trace gases, which are atmospheric constituents present in small amounts, from about 400 kilometers above Mars. The agency credits the orbiter with the first detection of hydrogen chloride in the Martian atmosphere and with measurements related to water loss. It also reports that TGO monitors radiation and maps water ice beneath the surface.
TGO’s imaging system has mapped more than 10% of Mars in four colors, ESA says. Those maps support scientific work and studies of potential landing sites for the Rosalind Franklin rover.
On methane, ESA says TGO has not detected the gas described in earlier reports. The difference between that result and other observations remains a research question.
How TGO’s role has changed
TGO was designed to relay communications between Mars and Earth for surface missions. ESA says it can store data from the Martian surface during solar conjunctions, when regular communication with Earth is paused, and transmit the stored data later.
The orbiter’s radio equipment, designed for communication with the surface, is also being used with Mars Express for atmospheric radio science. And in 2024, ESA uploaded flight software that limits gyroscope use to help preserve the instruments for the arrival of the Rosalind Franklin rover.
