NASA narrows Mars 2020 mission to three drill sites

NASA’s Mars 2020 mission is edging tantalisingly closer. After a workshop with scientists in Monrovia, California, three potential sites have been chosen for drilling, each of which could have once supported life on the red planet.

The trio of locations has been whittled down from eight, after scientists pored through images and data sent by the Mars Reconnaissance Orbiter, then voted on which were most likely to have supported life. Amongst the lineup – and the highest scoring in the workshop’s community vote – is an ancient lake bed, known as Jezero crater, which could be home to traces of microbial lifeforms.

“You’ve got a large river bringing water and sediment into a very large lake, comparable to Lake Tahoe,” Timothy Goudge, a planetary scientist at the University of Texas at Austin, told Nature.

Second in the vote was Northeast Syrtis, which once had hot water circulating beneath its crust. The final, and potentially most controversial choice, is Columbia Hills.

The site has previously been the prowling ground for NASA’s Spirit rover, which found silica rocks that resemble hydrothermal mineral deposits on Earth. A number of scientists on the 2020 project have gone so far as to publish a report claiming the mission won’t be able to shed light on whether these rocks are linked to life on Mars. Other scientists have pointed to the fact that the 2020 rover will have different scientific instruments, more capable of analysing the silica rock than Spirit.

The final choice of site, expected a couple of years before the mission, will have major repercussions for the next decades of science around Mars. Wherever the rover ends up going, it will spend two years drilling for samples. NASA will then have to work out how to get the samples back to earth – and amass the budget to do so – but if it manages it, those samples will be the first Mars rocks not to come from meteorites and will dictate study for years to come.

Lead image: Jezero crater. Credit: NASA