NASA’s Perseverance rover has picked up a rocky hitchhiker on Mars.
The rover recovered a “pet rock” hidden inside its left front wheel that has been rolling with Perseverance since early February. So far he has traveled 8.5 kilometers with the Perseverance rover as it passes through his Jezero Crater home on Mars.
“This rock isn’t damaging the wheel, but throughout its (undoubtedly bumpy!) journey it snagged and made periodic appearances in our left-wing Hazcam footage,” said Eleni Ravanis, a student collaborator on NASA’s Perseverance mission from the University of Hawaii at Mānoa, wrote in an update (opens in a new tab).
Related: The Perseverance rover captures stunning video of a solar eclipse on Mars
According to Ravanis, Perseverance picked up the small boulder from Mars on February 4, the rover’s 341st day (or Sol as Mars days are called) on the Red Planet. At the time, Perseverance was exploring a rock formation called “Máaz” which scientists believe is made up of ancient lava flows.
Since then, Perseverance has carried the boulder north through its landing site, named after the famous late science fiction author Octavia E. Butler, and then west through the remains of an area called “Kodiak “, the remains of an ancient delta in Jezero. The rover is currently in the midst of what NASA calls its Delta Front campaign and may have drilled into its first sedimentary rock from Mars, Ravanis wrote.
“The Rock of Perseverance is now far from home,” Ravanis wrote. “It is possible that the rock will fall at some point during our future ascent from the crater rim. If so, it will land among rocks that we expect to be very different from itself.”
If that happens, a future Martian geologist might be a bit confused to find the rock so out of place, Ravanis added.
Hitchhiking rocks are no stranger to NASA’s Mars rovers.
In 2004, the Spirit rover picked up what Ravanis described as a “potato-sized” rock in its right rear wheel which eventually had to be dislodged. Perseverance’s cousin, the former Curiosity rover which will celebrate its 10th anniversary on Mars in August, has also occasionally picked up rocks in its own beaten wheels as it pursues its own mission in Mars’ Gale crater.
“While it’s unclear exactly how long these boulders remained, they tended to pop off after a few weeks,” Ravanis wrote. “Perseverance’s current companion is on course to break hitchhiking records on Mars!”