Perseverance has been on Mars for over a year, continuously streaming images of the Red Planet. We saw Jezero Crater itself, as well as thousands of snapshots of the Martian landscape and sky. Perseverance also takes periodic selfies, to check its condition and calibrate its sensors. But it’s lonely out there on the red planet. So, a few months ago, the rover picked up a companion. Tucked inside one of its wheels, Perseverance has a pet rock.
It’s not AIBO or K-9, but of course that rock has been tumbling on Perseverance’s heels for months. Mission scientists believe the rock came from debris the rover picked up during its travels through Jezero. In a blog post, Perseverance team member Eleni Ravanis said the rock may have come from lava flows in the “Máaz” formation of Jezero Crater. But that’s not all that makes it special.
This isn’t the first time a boulder has hitched a ride on a Mars rover mission. Both Spirit and Curiosity have had their own travel companions. But it’s the longest we’ve ever seen a rover clinging to the same rock. “While it’s unclear exactly how long these boulders remained, they tended to pop off after a few weeks,” Ravanis said. “Perseverance’s current companion is on course to break hitchhiking records on Mars!”
Perseverance first filmed her pet in February. “It’s not seen as a risk. We have also seen these types of rocks get ‘caught’ in Curiosity’s wheels from time to time,” a JPL spokesperson explained. “They happen on cross-slope rides and tend to fall off on their own after a while (there is no particular way to get this rock out of our ‘shoe’). These kind of pebbles n has no impact on driving except that it is a little noisier.
Since Perseverance retrieved their pet rock, the duo have covered more than 8 km. We don’t know if the rock will fall or stay with the rover. But if he goes, he will fall among rocks very different from him. Perseverance is currently cruising Hawksbill Gap, a route to the top of the Three Forks River Delta. But the rocks he sampled on May 29, 2022 (Sol 452) look like sedimentary rocks. A lava stone would be far from the Shire indeed.
So far, the Perseverance rover has collected eight rock cores. The rover has now entered its Delta Front science campaign. And he recently got permission from NASA to “choose his own targets to zap.” But it seems Perseverance got its pet rock by pure chance. In the blog post, Ravanis joked, “How do you choose a rock on Mars? Sometimes you don’t – he chooses you.