  After the successful landing of the Mars Science Laboratory rover, both NASA
and ESA initiated a selection process for potential landing sites for the
Mars2020 and ExoMars missions, respectively. Two ellipses located in the Mawrth
Vallis region were proposed and evaluated during a series of meetings (3 for
Mars2020 mission and 5 for ExoMars). We describe here the regional context of
the two proposed ellipses as well as the framework of the objectives of these
two missions. Key science targets of the ellipses and their astrobiological
interests are reported. This work confirms the proposed ellipses contain
multiple past Martian wet environments of subaerial, subsurface and/or
subaqueous character, in which to probe the past climate of Mars, build a broad
picture of possible past habitable environments, evaluate their exobiological
potentials and search for biosignatures in well-preserved rocks. A mission
scenario covering several key investigations during the nominal mission of each
rover is also presented, as well as descriptions of how the site fulfills the
science requirements and expectations of in situ martian exploration. These
serve as a basis for potential future exploration of the Mawrth Vallis region
with new missions and describe opportunities for human exploration of Mars in
terms of resources and science discoveries.
