After being together for more than half of Perseverance's mission, the NASA Mars rover and its so-called "pet rock" have separated. A rock managed to lodge itself in the rover's front left wheel on Feb. 4, 2022, almost a year after Perseverance landed on the red planet on Feb. 18, 2021. As of last week, the rock had become dislodged, as revealed in an image NASA released from April 18. As LiveScience reports, in addition to showing up in photos of the rover, the rock managed to "cling on despite several vigorous maneuvers across the planet's surface" for 439 days. Gizmodo notes it had "gained somewhat of a cult following," and so of course there were people on social media lamenting its disappearance.
The rock was not a hazard to Perseverance's mission; experts said it was like "having a pebble stuck in your shoe." Other rocks picked up by the rover in its wheels all fell out within a matter of days. Rocks lodged in other areas of the rover, however, can become an issue. In December 2021, scientists had to figure out how to get multiple small pebbles out of Perseverance's inner machinery before it could resume operations, and back in 2004, NASA's Spirit rover was made to perform a sharp turn to dislodge a "potato-sized" rock from one of its wheels because scientists were worried it would damage the rover. (More Perseverance stories.)