The ExoMars Trace Gas Orbiter - First Martian Year in Orbit

The Trace Gas Orbiter, TGO, concluded its first Martian year in orbit in March 2020. It has been a highly successful Martian year, starting with the rise, plateau and decay of the major Global Dust Storm in the summer of 2018. This has enabled interesting results to be derived on the dynamic behaviour as a consequence of the dust storm. One of the significant observations is a strong upward transport of water vapour that has been found during this time. Characterisations of the minor species and trace gasses are continuing and large numbers of profiles are being produced on a daily basis. A dedicated search of methane has shown that there is no methane above an altitude of a few km, with an upper limit established at about 20 pptv (2∙10^-11).

The solar occultation technique applied by the spectrometers has definitely proven its strength, both for its high sensitivity and for its capability of making high-resolution altitude profiles of several parameters in the atmosphere. Climatological studies, benefitting from the 400km, 74 degrees inclination non-solar synchronous orbit, have been initiated and will become more important now that a full year has passed, even if the full potential will be visible only after a few Martian years of operation. The FREND instrument has characterised the hydrogen in the shallow sub-surface on a global scale, at a spatial resolution much better than previous missions have been able to do. It has found areas at surprisingly low latitudes with significant amounts of sub-surface hydrogen, most likely in the form of water ice. The CaSSIS camera has made a high number of images over a large variety of targets, including the landing sites of the 2020 NASA and 2022 ESA rovers, Oxia Planum and the Jezero Crater. Stereo imaging has enabled topographic information and precise 3-D landscape synthesis.

This presentation will summarise the highlights of the first Martian year and discuss planned activities for the near and medium term future.

The ExoMars programme is a joint activity by the European Space Agency (ESA) and ROSCOSMOS, Russia. It consists of the ExoMars 2016 mission, launched 14 March 2016, with the Trace Gas Orbiter, TGO, and the Entry Descent and Landing Demonstrator, EDM, named Schiaparelli, and the ExoMars 2020 mission, to be launched in July/August 2020, carrying a Rover and a surface science platform to the surface of Mars.