ESA - Robotic Exploration of Mars - ExoMars landing sites to narrow to final two

ExoMars 2020 rover and surface platform. Credit: ESA/ATG medialab

The ExoMars rover and surface platform will launch in 2020. The primary objective is to land at a site with high potential for finding well-preserved organic material, particularly from the very early history of the planet.

While the surface platform will remain stationary at the landing site, the rover is expected to travel several kilometres during its time on Mars, and to drill down to two metres below the surface to collect samples for analysis in the rover's onboard laboratory. Underground samples are more likely to include possible chemical biosignatures in a good state of conservation, since the tenuous martian atmosphere offers little protection from radiation to complex molecules at the surface.

At the previous landing site selection workshop, which took place in October 2015, the Landing Site Selection Working Group (LSSWG) chose three landing sites for detailed study. At the time, the ExoMars rover was scheduled for launch in 2018 and Oxia Planum was identified as the primary choice.

Oxia Planum is a low-lying area that contains significant clay-bearing rocks. This indicates that water was once abundant here.

A further recommendation was made to also consider Oxia Planum as one of the two candidate landing sites for the backup launch opportunity in 2020, with a second to be selected from Aram Dorsum and Mawrth Vallis after due consideration.

Aram Dorsum is a flat region near the martian equator that includes the remains of a meandering channel and its surrounding flood plains. Mawrth Vallis contains many fine-layered, clay-rich sedimentary deposits that signal the presence of much water.

Potential landing sites for ExoMars 2020. Oxia Planum (indicated in green) was identified, at the 3rd Landing Site Selection Workshop, as one of the two candidate landing sites, with a second to be chosen between Aram Dorsum and Mawrth Vallis (both indicated in blue). Credit: ESA/CartoDB

Now that launch is scheduled for 2020, the LSSWG must come together again and narrow this choice to just two sites.

Each landing site team will present the results of their investigations. They will highlight the expected scientific diversity of the site, the accessibility of the interesting geological landforms, the driving conditions for the rover, and provide an example of a mission that could be conducted while traversing 3 kilometres on the surface.

On the second day of the workshop, the participants will vote on the relative merits of the three sites. The results will be taken into account but the final decision of which two sites to take forward will rest solely with the LSSWG. Their recommendations and reasons will be presented on the afternoon of 28 March.

The final decision about where to land the rover is expected to take place no later than mid-2019.

ExoMars is a joint endeavour between ESA and Roscosmos, with important contribution from NASA.