Mars 2020 Perseverance Rover will hunt for fossils using x-rays

NASA currently expects to land the Mars 2020 Perseverance rover on the surface of Mars on February 18, 2021. Once the rover is on the surface and working, it will begin to search for traces of microscopic life that could be billions of years old. The rover is fitted with an instrument called PIXL, which is a lunchbox-sized device at the end of the seven-foot-long robotic arm fitted to the rover.Inside that box is a powerful and finally-focused x-ray beam that will be used to discover where and in what quantity chemicals are distributed across the surface of Mars. The x-ray beam is so narrow it's able to pinpoint features as small as a grain of salt. NASA researcher Abigail Allwood says that the precision allows the team to very accurately tie chemicals detected to specific textures in a rock.

Rock textures are an essential clue in deciding what samples are worth returning to Earth. Researchers point out that on Earth, distinctively warped rocks called stromatolites are made from ancient layers of bacteria and are an example of fossilized ancient life that scientists will be looking for on the Red Planet. PIXL uses more than an x-ray beam alone, it also has a hexapod, which is a device featuring six mechanical legs connected to the robotic arm guided by AI to get the most accurate aim possible.

Once near a target rock, PIXL uses a camera and laser to calculate distance. The legs then make tiny movements on the order of around 100 microns so the device can scan the target mapping the chemicals found in a postage-stamp-sized area. X-rays are emitted in 10-second bursts aiming at a single point on the rock before the instrument tilts 100 microns and takes another measurement. Taking accurate measurements of a very small area could take as long as nine hours.