PIXL Instrument on NASA’s Perseverance Studies ‘Bills Bay’

Analyzing this abraded rock patch dubbed “Bills Bay,” the PIXL instrument on NASA’s Perseverance Mars rover found it rich in carbonates and silica, both of which are good at preserving signs of ancient life.
December 12, 2023
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Before collecting a rock sample at a spot nicknamed “Lefroy Bay,” NASA’s Perseverance Mars rover employed an abrasion tool to wear down the rock surface and then used the Planetary Instrument for X-ray Lithochemistry, or PIXL, to study the rock’s internal chemistry. This image is composed of multiple shots of the abrasion patch, dubbed “Bills Bay,” that were taken on Oct. 7 and Oct. 11, 2023, the 935th and 939th Martian days, or sols, of the mission.

The image was taken by PIXL’s camera, the Autofocus and Context Imager, or ACI. Color was added by overlaying data from WATSON (Wide Angle Topographic Sensor for Operations and eNgineering), a pair of cameras that are part of an instrument called Scanning Habitable Environments with Raman & Luminescence for Organics & Chemicals, or SHERLOC.

Figure A
Figure A is the same image of Bills Bay with a scale bar added.
Figure B
Figure B is the image of Bills Bay overlaid with PIXL chemical data showing the rock is rich in carbonates and silica, both of which are ideal for recording paleoenvironmental information and preserving signs of ancient life. The purple-colored areas are sand grains made of iron-rich carbonate. The green-colored areas between the sand grains are silica, which acts like cement, holding the sand together as a rock.
Figure C
Figure C is an image from one of Perseverance’s navigation cameras of the Bills Bay abrasion patch (left) and the Lefroy Bay drill hole surrounded by a mound of drill fines.

On Earth, both silica and carbonates are good at preserving materials left behind by ancient life. Sand grains made of iron-rich carbonate are also mostly found in places on Earth that are good at protecting carbon-based materials known as organics. Organics can be made from both geological and biological sources; the Lefroy Bay sample does not necessarily show signs of ancient microbial life. Samples like Lefroy Bay would have to be brought back to Earth and studied with complex instruments in laboratories for scientists to confirm signs of ancient life, if indeed they are present.

WATSON was built by Malin Space Science Systems (MSSS) in San Diego and is operated jointly by MSSS and NASA’s Jet Propulsion Laboratory.

A key objective for Perseverance’s mission on Mars is astrobiology, including the search for signs of ancient microbial life. The rover will characterize the planet’s geology and past climate, pave the way for human exploration of the Red Planet, and be the first mission to collect and cache Martian rock and regolith (broken rock and dust).

Subsequent NASA missions, in cooperation with ESA (European Space Agency), would send spacecraft to Mars to collect these sealed samples from the surface and return them to Earth for in-depth analysis.

The Mars 2020 Perseverance mission is part of NASA’s Moon to Mars exploration approach, which includes Artemis missions to the Moon that will help prepare for human exploration of the Red Planet.

JPL, which is managed for NASA by Caltech in Pasadena, California, built and manages operations of the Perseverance rover.

For more about Perseverance: