JPL
Careers
Education
Science & Technology
JPL Logo
JPL Logo
Mars
.

NASA's New Mars Rover Will Use X-Rays to Hunt Fossils

Sep 22, 2020
In this illustration, NASA's Perseverance Mars rover uses the Planetary Instrument for X-ray Lithochemistry (PIXL), which will help search for signs of ancient microbial life in rocks.

In this illustration, NASA's Perseverance Mars rover uses the Planetary Instrument for X-ray Lithochemistry (PIXL), which will help search for signs of ancient microbial life in rocks.

Credit: NASA/JPL-Caltech
Full Image Details
PIXL requires pictures of its rock targets to autonomously position itself. Using artificial intelligence, PIXL relies on the images to determine how far away it is from a target to be scanned.
PIXL requires pictures of its rock targets to autonomously position itself. Using artificial intelligence, PIXL relies on the images to determine how far away it is from a target to be scanned.
Credit: NASA/JPL-Caltech
Full Image Details

PIXL, an instrument on the end of the Perseverance rover's arm, will search for chemical fingerprints left by ancient microbes.

NASA's Mars 2020 Perseverance rover has a challenging road ahead: After having to make it through the harrowing entry, descent, and landing phase of the mission on Feb. 18, 2021, it will begin searching for traces of microscopic life from billions of years back. That's why it's packing PIXL, a precision X-ray device powered by artificial intelligence (AI).

Short for Planetary Instrument for X-ray Lithochemistry, PIXL is a lunchbox-size instrument located on the end of Perseverance's 7-foot-long (2-meter-long) robotic arm. The rover's most important samples will be collected by a coring drill on the end of the arm, then stashed in metal tubes that Perseverance will deposit on the surface for return to Earth by a future mission.

Get the Latest JPL News

SUBSCRIBE TO THE NEWSLETTER

Nearly every mission that has successfully landed on Mars, from the Viking landers to the Curiosity rover, has included an X-ray fluorescence spectrometer of some kind. One major way PIXL differs from its predecessors is in its ability to scan rock using a powerful, finely-focused X-ray beam to discover where - and in what quantity - chemicals are distributed across the surface.

"PIXL's X-ray beam is so narrow that it can pinpoint features as small as a grain of salt. That allows us to very accurately tie chemicals we detect to specific textures in a rock," said Abigail Allwood, PIXL's principal investigator at NASA's Jet Propulsion Laboratory in Southern California.

Rock textures will be an essential clue when deciding which samples are worth returning to Earth. On our planet, distinctively warped rocks called stromatolites were made from ancient layers of bacteria, and they are just one example of fossilized ancient life that scientists will be looking for.

A device with six mechanical legs, the hexapod is a critical part of the PIXL instrument aboard NASA's Perseverance Mars rover. The hexapod allows PIXL to make slow, precise movements to get closer to and point at specific parts of a rock's surface.
A device with six mechanical legs, the hexapod is a critical part of the PIXL instrument aboard NASA's Perseverance Mars rover. The hexapod allows PIXL to make slow, precise movements to get closer to and point at specific parts of a rock's surface.
Credit: NASA/JPL-Caltech
Full Image Details

An AI-Powered Night Owl

To help find the best targets, PIXL relies on more than a precision X-ray beam alone. It also needs a hexapod - a device featuring six mechanical legs connecting PIXL to the robotic arm and guided by artificial intelligence to get the most accurate aim. After the rover's arm is placed close to an interesting rock, PIXL uses a camera and laser to calculate its distance. Then those legs make tiny movements - on the order of just 100 microns, or about twice the width of a human hair - so the device can scan the target, mapping the chemicals found within a postage stamp-size area.

"The hexapod figures out on its own how to point and extend its legs even closer to a rock target," Allwood said. "It's kind of like a little robot who has made itself at home on the end of the rover's arm."

Then PIXL measures X-rays in 10-second bursts from a single point on a rock before the instrument tilts 100 microns and takes another measurement. To produce one of those postage stamp-size chemical maps, it may need to do this thousands of times over the course of as many as eight or nine hours.

That timeframe is partly what makes PIXL's microscopic adjustments so critical: The temperature on Mars changes by more than 100 degrees Fahrenheit (38 degrees Celsius) over the course of a day, causing the metal on Perseverance's robotic arm to expand and contract by as much as a half-inch (13 millimeters). To minimize the thermal contractions PIXL has to contend with, the instrument will conduct its science after the Sun sets.

"PIXL is a night owl," Allwood said. "The temperature is more stable at night, and that also lets us work at a time when there's less activity on the rover."

PIXL opens its dust cover during testing at NASA's Jet Propulsion Laboratory. One of seven instruments on NASA's Perseverance Mars rover, PIXL is located on the end of the rover's robotic arm.
PIXL opens its dust cover during testing at NASA's Jet Propulsion Laboratory. One of seven instruments on NASA's Perseverance Mars rover, PIXL is located on the end of the rover's robotic arm.
Credit: NASA/JPL-Caltech
Full Image Details

X-rays for Art and Science

Long before X-ray fluorescence got to Mars, it was used by geologists and metallurgists to identify materials. It eventually became a standard museum technique for discovering the origins of paintings or detecting counterfeits.

"If you know that an artist typically used a certain titanium white with a unique chemical signature of heavy metals, this evidence might help authenticate a painting," said Chris Heirwegh, an X-ray fluorescence expert on the PIXL team at JPL. "Or you can determine if a particular kind of paint originated in Italy rather than France, linking it to a specific artistic group from the time period."

For astrobiologists, X-ray fluorescence is a way to read stories left by the ancient past. Allwood used it to determine that stromatolite rocks found in her native country of Australia are some of the oldest microbial fossils on Earth, dating back 3.5 billion years. Mapping out the chemistry in rock textures with PIXL will offer scientists clues to interpret whether a sample could be a fossilized microbe.

More About the Mission

A key objective for Perseverance's mission on Mars is astrobiology, including the search for signs of ancient microbial life. The rover will also characterize the planet's climate and geology, pave the way for human exploration of the Red Planet, and be the first planetary mission to collect and cache Martian rock and regolith (broken rock and dust). Subsequent missions, currently under consideration by NASA in cooperation with the European Space Agency, would send spacecraft to Mars to collect these cached samples from the surface and return them to Earth for in-depth analysis.

The Mars 2020 mission is part of a larger program that includes missions to the Moon as a way to prepare for human exploration of the Red Planet. Charged with returning astronauts to the Moon by 2024, NASA will establish a sustained human presence on and around the Moon by 2028 through NASA's Artemis lunar exploration plans.

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

Learn more about the Mars 2020 mission at:

https://www.nasa.gov/perseverance

http://mars.nasa.gov

News Media Contact

Andrew Good

Jet Propulsion Laboratory, Pasadena, Calif.

818-393-2433

andrew.c.good@jpl.nasa.gov

Alana Johnson

NASA Headquarters, Washington

202-672-4780 / 202-358-0668

alana.r.johnson@nasa.gov

2020-183

Related News

Mars .

Testing Proves Its Worth With Successful Mars Parachute Deployment

Mars .

NASA’s Perseverance Rover Gives High-Definition Panoramic View of Landing Site

Mars .

NASA to Reveal New Video, Images From Mars Perseverance Rover

Mars .

NASA's Mars Perseverance Rover Provides Front-Row Seat to Landing, First Audio Recording of Red Planet

Mars .

NASA’s Perseverance Rover Sends Sneak Peek of Mars Landing

Mars .

NASA’s Mars Helicopter Reports In

Mars .

Touchdown! NASA’s Mars Perseverance Rover Safely Lands on Red Planet

Mars .

Searching for Life in NASA’s Perseverance Mars Samples

Mars .

NASA’s Next Mars Rover Is Ready for the Most Precise Landing Yet

Mars .

The Mars Relay Network Connects Us to NASA’s Martian Explorers

Explore More

Image .

Kaiser Crater Dunes

Image .

Crater Dunes

Topic .

Mars

Image .

Mastcam-Z's First 360-Degree Panorama

Image .

Black and White: Smoke Plume from Perseverance's Descent Stage

Image .

Halley Crater Dunes

Image .

Angustus Labyrinthus - Inca City

Image .

Mars Decoder Ring

Image .

Close-Up of Perseverance Heat Shield on the Martian Surface

Image .

Navcam View of Perseverance's Rover Deck

About JPL
Who We Are
Executive Council
Directors of JPL
JPL History
Documentary Series
Virtual Tour
Annual Reports
Missions
All
Current
Past
Future
News
All
Earth
Mars
Solar System
Universe
Technology
Galleries
Images
Videos
Audio
Podcasts
Infographics
Engage
JPL and the Community
Lecture Series
Public Tours
Events
Team Competitions
JPL Speakers Bureau
Topics
Solar System
Mars
Earth
Climate Change
Stars and Galaxies
Exoplanets
Technology
JPL Life
For Media
Contacts and Information
Press Kits
More
Asteroid Watch
Robotics at JPL
Subscribe to Newsletter
Universe Newsletter
Social Media
Get the Latest from JPL
Follow Us

JPL is a federally funded research and development center managed for NASA by Caltech.

More from JPL
Careers Education Science & Technology Acquisitions JPL Store
Careers
Education
Science & Technology
Acquisitions
JPL Store
Related NASA Sites
Basics of Spaceflight
Climate Kids
Earth / Global Climate Change
Exoplanet Exploration
Mars Exploration
Solar System Exploration
Space Place
NASA's Eyes Visualization Project
Voyager Interstellar Mission
NASA
Caltech
Privacy
Image Policy
FAQ
Feedback
Site Manager: Veronica McGregor
Site Editors: Tony Greicius, Randal Jackson, Naomi Hartono