It may be unscientific personification to think of the Perseverance rover as being lonely on Mars, but now it turns out to have adopted a pet rock.

NASA recently discovered the rock has been stuck in Perseverance’s wheel since early February. So far it’s hitched a ride totalling 5.3 miles. It was discovered thanks to the above image, taken from a camera that’s designed to spot hazards on the ground.

According to NASA, it’s not the first time a rover has picked up a rock, but it is the first time one has stayed in place for more than a few weeks.

Back in 2004, controllers intentionally turned the Spirit rover to dislodge a “potato-size” rock to reduce the risk of it working its way deeper into the wheel well.

NASA says the rock in Perseverance doesn’t appear to be doing any damage, so for now they’ll leave the rover on its original course.

They noted that if the rock does later fall out, it’s likely to be in very different surroundings from its “home.” It was picked up when Perseverance was examining rocks believed to be from lava flows. In its new position, Perseverance appears to have scraped into sedimentary rock for the first time.

Indeed, NASA staffers are already joking about a future geologist being very confused finding the rock out of place.