Courtesy: New Scientist
Voting has closed the results are in. The list of places where NASA’s next Mars rover, due to launch in 2020, could land has been narrowed down to three: Jezero crater, the dry remains of an ancient lake; Northeast Syrtis, which used to host hot springs; and the Columbia Hills, previously explored by NASA’s Spirit rover.
During a three day workshop in California, eight different landing sites were presented and put to a vote. These options were already whittled down from the 30 potential sites identified in 2015.
The emphasis of NASA’s Mars 2020 mission is searching for signs of life, whilst also laying the ground work for future missions to return samples to Earth. Bringing back souvenirs from Mars will be difficult and expensive, so NASA need to make sure they choose the best location to collect them from.
Top of the shortlist at the moment is Jezero crater, which used to be home to a lake the size of Lake Winnipeg in Canada. Microbes may have lived there during the wet periods in Jezero’s history, and researchers hope that signs of them are preserved somewhere near the surface.
Second place went to Northeast Syrtis, which used to be warmed by volcanic activity. This created hot springs that flowed to the surface and melted ice there. Northeast Syrtis has a layered terrain that has recorded the interactions of mineral and water over the years. It may also contain biosignatures from early Martian history.
The third and final spot in the shortlist went to the Columbia Hills, even though it actually came fifth in the popular vote. The workshop voting was only advisory, so NASA’s project scientists and engineers could prioritise other sites.
The Spirit rover had previously discovered that hot springs used to flow in the Columbia Hills as well, making it another area where life may have existed and been preserved.
“We had lots of really good options going in, so we couldn’t really go wrong with any of them,” says Tanya Harrison at Arizona State University.
That being said, she was surprised that the Columbia Hills were bumped up the list. The reasons behind that decision have not yet been released. “We’re sending a $2.5 billion spacecraft to Mars. To get the most bang for our buck we should go somewhere we’ve never been before,” says Harrison.