Rover Mission Now Being Built at JPL will Carry Home a Piece of Mars on 2020 Mission

Published : Thursday, February 15, 2018 | 4:00 PM

Rohit Bhartia of NASA's Mars 2020 mission holds a slice of a meteorite scientists have determined came from Mars. One of two slices will be used for testing a laser instrument for NASA's Mars 2020 rover while it's still on Earth; the other slice will go to Mars onboard the rover. Image Credit: NASA/JPL-Caltech

NASA’s Mars 2020 rover mission, now being built at the agency’s Jet Propulsion Laboratory in Pasadena, will be carrying a piece of meteorite that scientists have determined came from Mars’ surface millions of years ago.

A piece of a meteorite called Sayh al Uhaymir 008 (SaU008) will be carried on board the 2020 rover mission whose goal is to collect samples from the Red Planet’s surface that a future mission could potentially return to Earth.

The Meteoritical Society has confirmed only 200 of such Martian meteorites, and keeps a database listing these vetted meteorites. This chunk off SaU880 will be used as target practice for a high-precision laser on the rover’s arm, according to a JPL news release.

When Mars 2020 reaches Mars, it will be collecting samples from the surface that a future mission could potentially return to Earth. One of the rover’s many tools will be a laser designed to illuminate rock features as fine as a human hair. To calibrate that level of precision, a target – which may be a rock, metal or glass – is required so technicians could tweak the laser’s settings.

That sparked the interest of JPL scientists who asked: “Why not use an actual piece of Mars?”

“We’re studying things on such a fine scale that slight misalignments, caused by changes in temperature or even the rover settling into sand, can require us to correct our aim,” said Luther Beegle of JPL. Beegle is principal investigator for a laser instrument called SHERLOC (Scanning Habitable Environments with Raman and Luminescence for Organics and Chemicals). “By studying how the instrument sees a fixed target, we can understand how it will see a piece of the Martian surface.”

SHERLOC will be the first instrument on Mars to use Raman and fluorescence spectroscopies, which are scientific techniques familiar to forensics experts. Whenever an ultraviolet light shines over certain carbon-based chemicals, they give off the same characteristic glow that you see under black light.

Scientists can use this glow to detect chemicals that form in the presence of life. SHERLOC will photograph the rocks it studies, and then map the chemicals it detects across those images. That adds a spatial context to the layers of data Mars 2020 will collect.

“This kind of science requires texture and organic chemicals—two things that our target meteorite will provide,” said JPL’s Rohit Bhartia, SHERLOC’s deputy principal investigator.

To select the right Martian meteorite for SHERLOC, JPL turned to contacts at NASA’s Johnson Space Center in Houston, as well as the Natural History Museum of London. Not just any Martian meteorite would do: its condition would need to be solid enough that it would not flake apart during the intensity of launch and landing.

It also needed to possess certain chemical features to test SHERLOC’s sensitivity. These had to be reasonably easy to detect repeatedly for the calibration target to be useful.

Experts tried several samples, cutting off thin bits to test whether they would crumble. Using a “flaky” sample could damage the entire meteorite in the process.

The SHERLOC team ultimately agreed on using SaU008, which was found in Oman in 1999. Besides being more rugged than other samples, a piece of it was available courtesy of Caroline Smith, principal curator of meteorites at London’s Natural History Museum.

“Every year, we provide hundreds of meteorite specimens to scientists all over the world for study,” Smith said. “This is a first for us: sending one of our samples back home for the benefit of science.”

SaU008 will be the first Martian meteorite to have a fragment return to the planet’s surface – though not the first on a return trip to Mars. NASA’s Mars Global Surveyor included a chunk of a meteorite known as Zagami. It’s still floating around the Red Planet onboard the now-defunct orbiter.

Additionally, the team behind Mars 2020′s SuperCam instrument will be adding another Martian meteorite to their own calibration target.

Along with its own Martian meteorite, SHERLOC’s calibration target will include several interesting scientific samples for human spaceflight. These include materials that could be used to make spacesuit fabric, gloves and a helmet’s visor.

By watching how they hold up under Martian weather, including radiation, NASA will be able to test these materials for future Mars missions.

“The SHERLOC instrument is a valuable opportunity to prepare for human spaceflight as well as to perform fundamental scientific investigations of the Martian surface,” said Marc Fries, a SHERLOC co-investigator and curator of extraterrestrial materials at Johnson Space Center. “It gives us a convenient way to test material that will keep future astronauts safe when they get to Mars.”