BLOGMARS PERSEVERANCE ROVER


Laser Marking on Mars
Mars Perseverance Sol 471 - SuperCam Camera: Three dark laser pits in the shape of a slightly tilted letter “L” were produced in the rock surface of target “Pinefield Gap” (Sol 471) as a dry run for marking the surface of a sample core. The L mark is a way to maintain knowledge of the rotational orientation of the rock after the core is cut from the same location. The original orientation of the surface of the core will be useful to understand the original directions of magnetic domains in the samples after they are brought back to Earth. The L is 2.5 mm tall by 1.0 mm long (0.1” x 0.04”). The SuperCam instrument produced the laser pits using 125 shots in each pit, and also took this image. Credits: NASA/JPL-Caltech/LANL/CNES/IRAP. Download image ›

If your name begins with “L” you will like this post about the first letter to be laser engraved on Mars. Every once in a while, we see cartoons in which a Mars rover is driven in a pattern to make letters in the sand with its wheel tracks. The letters spell out a silly phrase, and the cartoon usually has aliens on the side, laughing or puzzling over the meaning. The use of lasers on board Mars rovers has also made it possible to laser-mark graffiti on Martian rocks. As NASA’s instruments are generally used strictly for science, I did not believe laser graffiti would ever be done. But of course, people have thought about it. When I arrived at JPL for the landing of Curiosity in 2012, I was surprised to find that one of our engineers in charge of developing sequences for SuperCam’s predecessor had written a lengthy sequence that would use the laser to spell out the instrument’s name on the rock surface. It was all in fun--we never wasted our shots using that sequence. However, on Perseverance, we have found a reason to use laser marking. 

About two years ago I received a call from Professor Ben Weiss of the Massachusetts Institute of Technology asking about SuperCam’s laser marking capabilities. Ben had had just joined Perseverance as part of the Return Sample Science team, a group focusing on the collection of samples for return to Earth, with the purpose of ensuring that samples would be collected under the appropriate conditions to optimize their scientific value once back on Earth. Ben’s specialty is paleomagnetism. In terrestrial rocks, this is the study of the magnetism induced by the Earth’s magnetic field at the time of the rock’s formation. Mars currently has a very weak magnetic field, but Mars’ field strength in the past is largely unknown. It has important implications for the retention or loss of Mars’ atmosphere over time, among other things. Suffice it to say that we would love to use the samples returned from the Perseverance mission to fill in that knowledge gap.

To do that, for each Mars rock core sample that is returned, we need to know its original orientation. If the surfaces of those core samples have easily recognizable features, that’s no problem. That has been the case with the cores collected so far. However, if the surface is fine-grained, there may be nothing to distinguish its rotational orientation. In that case, we need to make artificial markings on the surface. 

We don’t have a dark marker pen, but we do have a pulsed laser. So Ben’s call to my lab a couple of years ago got us thinking how to mark the sample cores, and we started some tests. JPL shipped several rocks of varying hardness to Los Alamos National Laboratory where they were marked with pits made with different numbers of laser shots. The rocks were sent back to JPL for subsequent coring.

NASA's Mars Perseverance rover acquired this image using its Right Mastcam-Z camera. Mastcam-Z is a pair of cameras located high on the rover's mast.
Mars Perseverance Sol 498 - Right Mastcam-Z Camera: Image taken by the Mastcam-Z right camera taken on Sol 498 showing the two drill holes and abrasion patch on the Skinner Ridge rock surface. Credits: NASA/JPL-Caltech/ASU. Download image ›
Fast forward to summer 2022. The SuperCam team was asked to be ready to mark a rock for coring with just a few days of notice. I was on SuperCam operations, and seeing how soon we might need the marks, we decided to switch from a normal observation to a core-marking sequence as a dry run. We had prepared various patterns for the mark. The basic principle is to understand the rotational orientation of the core after it has been removed from the rock and placed in the sample tube. For that, any asymmetrical pattern such as an arrow, would do. However, wanting to be efficient, we decided to use the simplest such pattern, consisting of three points (or laser pits) with unequal distance between them, like a capital letter “L.” SuperCam normally performs line scans (a single row) or grid patterns. To produce the “L” shape, we took a 2x2 grid pattern and removed one point from the sequence, so the laser only made three pits. Using 125 laser shots per pit, the result is shown in the image of the “Pinefield Gap” target. Sample cores are 13 mm (0.5”) in diameter, so the L patterns should fit well on their top surfaces. With the dry run successful, we are ready to use the procedure to mark future samples.

Over the last week, Perseverance completed its second of two samples from Jezero crater’s delta formation, from the Skinner Ridge block at Hogwallow Flats. Over the weekend Perseverance drove about 25 meters to Wildcat Ridge, located slightly lower in Hogwallow, for more exploration.



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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Contributors+

  • Mariah Baker
    Planetary Scientist, Smithsonian National Air & Space Museum
    Washington, DC
  • Matthew Brand
    SuperCam/ChemCam Engineer, Los Alamos National LaboratoryLos Alamos National Laboratory
  • Sawyer Brooks
    Docking Systems Engineer, NASA/JPL
    Pasadena, CA
  • Adrian Brown
    Deputy Program Scientist, NASA HQ
    Washington, DC
  • Denise Buckner
    Student Collaborator, University of Florida
    Gainesville, FL
  • Fred Calef III
    Mapping Specialist, NASA/JPL
    Pasadena, CA
  • Alyssa Deardorff
    Systems Engineer, NASA/JPL
    Pasadena, CA
  • Kenneth Farley
    Project Scientist, Caltech
    Pasadena, CA
  • Phylindia Gant
    Mars 2020 Student Collaborator, University of Florida
    Gainesville, FL
  • Brad Garczynski
    Student Collaborator, Purdue University
    West Lafayette, IN
  • Erin Gibbons
    Student Collaborator, McGill University
    Montreal, Canada
  • Michael Hecht
    Mars Oxygen In-Situ Resource Utilization Experiment (MOXIE) Principal Investigator, Massachusetts Institute of Technology
    Westford, MA
  • Louise Jandura
    Chief Engineer for Sampling & Caching, NASA/JPL
    Pasadena, CA
  • Lydia Kivrak
    Student Collaborator, University of Florida
    Gainesville, FL
  • Rachel Kronyak
    Systems Engineer, NASA/JPL
    Pasadena, CA
  • Steven Lee
    Perseverance Deputy Project Manager, NASA/JPL
    Pasadena, CA
  • Justin Maki
    Imaging Scientist and Mastcam-Z Deputy Principal Investigator, NASA/JPL
  • Sarah Milkovich
    Assistant Science Manager, NASA/JPL
    Pasadena, CA
  • Eleanor Moreland
    Ph.D. Student, Rice University
    Houston, Texas
  • Matt Muszynski
    Vehicle Systems Engineer, NASA/JPL
    Pasadena, CA
  • Claire Newman
    Atmospheric Scientist, Aeolis Research
    Altadena, CA
  • Avi Okon
    Sampling Operations Deputy Lead, NASA/JPL
    Pasadena, CA
  • Pegah Pashai
    Vehicle Systems Engineer Lead, NASA/JPL
    Pasadena, CA
  • David Pedersen
    Co-Investigator, PIXL Instrument, Technical University of Denmark (DTU)
    Copenhagen, Denmark
  • Eleni Ravanis
    Student Collaborator, University of Hawaiʻi at Mānoa
    Honolulu, HI
  • Kathryn Stack
    Deputy Project Scientist, NASA/JPL
    Pasadena, CA
  • Vivian Sun
    Science Operations Systems Engineer, Staff Scientist, NASA/JPL
    Pasadena, CA
  • Iona (Brockie) Tirona
    Sampling Engineer, NASA/JPL
    Pasadena, CA
  • Jennifer Trosper
    Project Manager, NASA/JPL
    Pasadena, CA
  • Vandi Verma
    Chief Engineer for Robotic Operations, NASA/JPL
    Pasadena, CA
  • Rick Welch
    Deputy Project Manager, NASA/JPL
    Pasadena, CA
  • Roger Wiens
    Principal Investigator, SuperCam / Co-Investigator, SHERLOC instrument, Purdue University
    West Lafayette, IN

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:


CAMERAS & SPECTROMETERS
GROUND-PENETRATING RADAR
ENVIRONMENTAL SENSORS
TECHNOLOGY DEMO
SAMPLE COLLECTION

Where is the Rover?

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

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