BLOGMARS PERSEVERANCE ROVER


How the Rover Averts Collisions and Zaps
Mars Perseverance Sol 374 - Front Right Hazard Avoidance Camera: NASA's Mars Perseverance rover acquired this image of the area in front of it using its onboard Front Right Hazard Avoidance Camera A. This image was acquired on March 10, 2022 (Sol 374). Credits: NASA/JPL-Caltech. Download image ›

Perseverance has a number of moving parts, including the robotic arm, drill, mast, instrument covers, high gain antenna, and mobility system. An unintended collision with the rover body or Martian terrain during motion could cause irreparable damage. In addition, the SuperCam instrument shoots the LIBS laser at the surface to create a plasma and perform spectroscopy, and we also want to prevent the laser from zapping any part of the rover.

To avoid this, Perseverance checks upcoming moves and laser firing using its Rover Collision Model flight software and autonomously stops any activity before a collision could happen. To perform robotic arm collision checks Perseverance projects the next arm move into the future and checks if at any point in that move it would collide with the rover body. If the predicted move has no unexpected collisions, it allows commencing motion. At times the arm does need to get very close to hardware or even touch other parts of the rover body, such as during docking to exchange drill bits or cache sample. The rover knows when the contacts are intentional and allows them to occur. When Perseverance autonomously selects science targets onboard using AEGIS, it uses the Rover Collision Model to filter out any targets that may result in collisions before selecting a target for SuperCam targeting.

Typically the operations team sends commands to the rover once a sol and Perseverance needs to protect itself if some of those activities don’t go as planned. If the drill were to encounter even a minor fault, as occurred on Sol 374, the robotic arm could unexpectedly still be in front of the rover, touching the target. The planned LIBS firing in a continuation of the same plan the next morning was pointed to zap a rock that was now blocked by the arm. This was gracefully averted as intended by the Rover Collision Model on Sol 375.

Collision checking autonomously happens onboard, and the operations team does not typically perform any explicit commanding. Unless a move fails a collision check during ground simulation and needs to be adjusted, the operations team may not even notice it. Rover Collision Model was one of the flight software modules I designed and programmed, so I can’t help but think of what it’s doing in the background. As of sol 460, it has performed over 64,000 collision checks on Mars without error, reporting collisions where expected.

We’ve arrived at Hogwallow Flats. I’m looking forward to seeing the rover check for many more collisions and zaps as it performs some exciting science investigation.



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
  • Iona Brockie
    Sampling Engineer, NASA/JPL
    Pasadena, CA
  • 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
  • Brad Garczynski
    Student Collaborator, Purdue University
    West Lafayette, IN
  • Erin Gibbons
    Student Collaborator, McGill University
    Montreal, Canada
  • 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
  • Matt Muszynski
    Vehicle Systems Engineer, NASA/JPL
    Pasadena, CA
  • Avi Okon
    Sampling Operations Deputy Lead, NASA/JPL
  • 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
  • Vivian Sun
    Science Operations Systems Engineer, Staff Scientist, 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
  • 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

View Map ›