  In this paper we describe the first combined observations executed by the
Mars Express and Trace Gas Orbiter missions since the start of the TGO
operational phase in April 2018 until June 2019. Also included is the science
opportunity analysis that has been performed by the Science Operation Centres
and instrument teams to identify the observation opportunities until the end of
2020. These results provide a valuable contribution to the scientific community
by enabling collaborations within the instrument teams and enhance the
scientific outcome of both missions. This information is also valuable to other
Mars missions, which may be interested in observing these locations for wider
scientific collaboration.
