LOOK: This Picturesque Mars Valley Was Once ‘Potentially Habitable’

A valley in Mars is said to be once habitable and is a potential landing site for the European ExoMars 2020 mission.

The European Space Agency (ESA) released new images of Mawrth Vallis, one of the largest Martian valleys that scientists believed had been habitable about 3.6 billion years ago. A bird's-eye view of the valley was captured by ESA's Mars Express spacecraft, which has been orbiting the Red Planet since late 2003.

The image shows a region of over 330,000 square kilometers surrounding the valley that is sculpted by ancient water flowing on the surface. Mawrth Vallis is about 600 km long and 2 km deep, and large amounts of water had once passed through it from an elevated region and flowing into the northern plains, ESA said in a statement.

Some of the most notable features of the valley are the large exposures of weathered light-toned clay minerals known as phyllosilicates found along its course. The presence of phyllosilicates in Mars provides evidence that liquid water once existed on the planet and points to the possibility that the Red Planet once had habitable environments.

Remains of ancient volcanic ash form a dark cap of rock that covers some of the clays and scientists said it could have protected ancient microbes in the rocks from radiation and erosion. For this reason, Mawrth Vallis is one of the candidate landing sites for ExoMars 2020, which is a joint mission between ESA and the Russian federal space agency Roscosmos with the goal of finding evidence of ancient life on the Red Planet.

The ExoMars spacecraft launched on March 14 from the Baikonur Space Center in Kazakhstan on board a Proton-M carrier rocket. It consists of the Schiaparelli landing demonstrator module, which is tasked to test the technology needed for the landing of the rover, and the Trace Gas Orbiter (TGO), which will study the planet's rare gases.