Why and How Perseverance Abrades Rocks
NASA's Mars Perseverance rover acquired this image using its Left Mastcam-Z camera. Mastcam-Z is a pair of cameras located high on the rover's mast. Credits: NASA/JPL-Caltech/ASU. Download image ›

When the Perseverance rover finishes a drive and is exploring a new location, you may see it create a round, shallow hole in a nearby rock. Why does it do this, and how?

Mars rovers are robot geologists.  They study the rocks around them to understand how the area was formed.  However, the environment on the surface of Mars can dramatically change the exterior of a rock.  The unaltered rock below the surface may hold important clues to the history of the area.

The previous rovers Spirit and Opportunity each had a Rock Abrasion Tool (RAT), a high-speed grinder with brushes to remove that weathered outer layer of rock and clear away dust.  Perseverance creates abraded patches that look similar to the ones Spirit and Opportunity made, but it does so in a very different way.

Perseverance is equipped with a rotary percussive drill and a suite of interchangeable drill bits.  The sampling team had the task of being able to collect cores, collect regolith, and create abraded patches all using the same drill.

Close-up  photo of Perseverance rover's drill, with its abrading bit facing the camera. The bit has a flat surface, 5 centimeters in diameter, with linear teeth for grinding rocks.
Mars Perseverance Sol 160: Left Mastcam-Z Camera: NASA's Mars Perseverance rover acquired this image using its Left Mastcam-Z camera. Mastcam-Z is a pair of cameras located high on the rover's mast. Credits: NASA/JPL-Caltech/ASU. Download image ›

To do this, the abrading bits have an unusual tooth pattern: three parallel lines of different lengths, arranged asymmetrically.  When the drill spins and hammers with an abrading bit, that tooth pattern creates crisscrossing, well distributed impacts in the rock.  This chips away the surface and makes a smooth, flat patch of fresh rock about 2 inches (5 centimeters) in diameter.

However, the newly drilled abrasion is full of cuttings - the dust generated by drilling.  The cuttings hide what the scientists are interested in seeing: the color and shape of individual grains in the abrasion.  Perseverance removes the cuttings using another tool on the turret called the Gaseous Dust Removal Tool (GDRT).  The GDRT has a tank of nitrogen gas and uses four short puffs to blow the cuttings away and reveal the fresh rock surface underneath.

Close-up photo of a Mars rock with a shallow, 5-centimeter-wide hole drilled into it.
Mars Perseverance Sol 160: WATSON Camera: NASA's Mars Perseverance rover acquired this image using its SHERLOC WATSON camera, located on the turret at the end of the rover's robotic arm. Credits: NASA/JPL-Caltech. Download image ›

The rover can then use its suite of instruments to study the abrasion.  These observations provide insight into the formation of the area, and also help the team decide whether to take a core sample from that rock.

I started my career at JPL as a mechanical engineering intern working on the design of the abrading bit.  Seven years later, I helped drill our first abrasion on Mars.  I’m excited to hear what conclusions the scientists draw from their analysis, and to see what surprises our next abrasion holds.

About This Blog

These blog updates are provided by self-selected Mars 2020 mission team members who love to share what Perseverance is doing with the public.

Dates of planned rover activities described in these blogs are subject to change due to a variety of factors related to the Martian environment, communication relays and rover status.

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  • Iona Brockie
    Sampling Engineer, NASA/JPL
    Pasadena, CA
  • Denise Buckner
    Student Collaborator, University of Florida
    Gainesville, FL
  • Kenneth Farley
    Project Scientist, Caltech
    Pasadena, CA
  • Brad Garczynski
    Student Collaborator, Purdue University
    West Lafayette, IN
  • Louise Jandura
    Chief Engineer for Sampling & Caching, NASA/JPL
    Pasadena, CA
  • Louise Jandura
    Chief Engineer for Sampling & Caching, NASA/JPL
  • Rachel Kronyak
    Systems Engineer, NASA/JPL
    Pasadena, CA
  • Pegah Pashai
    Vehicle Systems Engineer Lead, NASA/JPL
    Pasadena, CA
  • Jennifer Trosper
    Project Manager, NASA/JPL
    Pasadena, CA
  • Roger Wiens
    Principal Investigator, SuperCam / Co-Investigator, SHERLOC instrument, LANL
    Los Alamos, NM

Tools on the Perseverance Rover+

The Perseverance rover has tools to study the history of its landing site, seek signs of ancient life, collect rock and soil samples, and help prepare for human exploration of Mars. The rover carries:


Where is the Rover?

Image of a rover pin-point at Perseverance's location on Mars, Jezero Crater

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