ExoMars TGO spacecraft orbiting Mars, artwork. The Trace Gas Orbiter (TGO) is under development by the European Space Agency (ESA) and the Russian Federal Space Agency (Roscosmos) as part of the ESA's ExoMars mission. This robotic orbiter-carrier could be launched in January 2016 and reach Mars in October of that year. On board would be the ExoMars EDM stationary lander, which would prepare for the later (2018) ExoMars lander rover. The TGO orbiter would remain in orbit, mapping Mars for sources of methane and other gases.