NASA Mars Rover's Battered Wheels Pick Up Hitchhiking Rock

NASA's Perseverance isn't the only rover with a red planet rock along for the ride.

Amanda Kooser
Amanda Kooser
Freelance writer Amanda C. Kooser covers gadgets and tech news with a twist for CNET. When not wallowing in weird gear and iPad apps for cats, she can be found tinkering with her 1956 DeSoto.
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Part of the Curiosity Mars rover's metal wheel with a flat brownish rock wedged in between two treads.
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Part of the Curiosity Mars rover's metal wheel with a flat brownish rock wedged in between two treads.

Curiosity's wheel rock is on the outside.

NASA/JPL-Caltech/MSSS/red circle by Amanda Kooser/CNET

Rolling around a Martian crater all by yourself may seem like a lonely existence, but NASA's Curiosity rover has picked up a little friend. An image from Aug. 31 shows a rock wedged onto one of the rover's wheels.

Image processor Kevin Gill brought my attention to the hitchhiker in a Twitter post over the weekend. "The Curiosity rover has picked up its own wheel rock buddy wedged in there between two of the grousers," Gill wrote. Grousers are the raised zig-zag parts of the wheels that act as treads.

The image is the equivalent of what happens when you get a pebble stuck in the tread of your shoe and you stop to inspect the underside. The rover traversed a tricky, rocky pass in August.

Curiosity isn't the only rover into accidental rock collecting. The Perseverance rover over in Jezero Crater managed to pick up an interloper inside one of its wheels. That rock has logged months of travel with Percy, but doesn't pose any risk to the vehicle's operation.

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Curiosity has been traipsing around the rugged and rocky Gale Crater since landing in 2012. It regularly images its wheels so the rover's team can track wear and tear. The aluminum wheels look pretty gnarly with cracks, holes and broken treads visible. The rover's team has taken steps to extend the life of the wheels and NASA expects them to hold up for the remainder of the mission. The space agency gave Curiosity a three-year mission extension back in April.

I've reached out to NASA to see if the rock is cause for concern considering the condition of Curiosity's wheels. It's located near a hole, but seems to be located on a solid part of the wheel. Future wheel monitoring images should be able to see if it's still there or if it jumped ship along the way. 

If the pet rock sticks around, maybe it will earn a name? I like "Rocky."