Artist’s impression of the ExoMars 2020 rover and Russia’s stationary surface platform in background.
ESA/ATG medialab

(Update: March 28, 2017)
Two ancient sites on Mars that hosted an abundance of water in the planet’s early history have been recommended as the final candidates for the landing site of the 2020 ExoMars rover and surface science platform: Oxia Planum and Mawrth Vallis.

The process to decide where Europe’s ExoMars rover will scout about on the Red Planet is underway this week.

In late 2015, one site – Oxia Planum – had been recommended as the primary focus for further detailed evaluation, with two other sites retained for discussion. Now experts will determine whether it will be Aram Dorsum or Mawrth Vallis that will also be put forward to study in further detail.

Landing sites

Aram Dorsum comes with a channel, curving from northeast to west across the location. The sedimentary rocks around the channel are thought to be alluvial sediments deposited much like those around Earth’s River Nile.

Mawrth Vallis is one of the oldest outflow channels on Mars, at least 3.8 billion years old. It hosts large exposures of finely layered clay-rich rocks, indicating that water once played a role here.

Oxia Planum contains one of the largest exposures of ancient – approximately 3.8 billion years old – clay-rich rocks on the planet. The finely layered formations record a variety of deposition and wetting environments believed to be similar to that of Mawrth Vallis.

Credit: ESA/ATG medialab


The European Space Agency’s (ESA) ExoMars rover and Russia’s stationary surface science platform are scheduled for launch in July 2020, arriving at Mars in March 2021.

A key objective of ExoMars is establishing whether life ever existed on Mars. Therefore the chosen site should be ancient – around 3.9 billion years old – with abundant evidence of water having been present for extended periods.

Drill depth

ESA’s rover is factory equipped with a drill that is capable of extracting samples from depths of over 6 feet (2 meters).

According to an ESA statement regarding drill depth, “this is crucial, because the present surface of Mars is a hostile place for living organisms owing to the harsh solar and cosmic radiation. By searching underground, the rover has more chance of finding preserved evidence.”

Drill samples are to be delivered to the Analytical Laboratory Drawer (ALD) in the body of the rover, via a sample delivery window.

ESA’s Trace Gas Orbiter, now in Mars orbit since October 2016, will serve as a relay station for the ExoMars rover mission, as it continues to press on with its own science agenda.

For an informative overview of the ESA Mars rover, go to:


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