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NASA Has a Plan to Dislodge the Pebbles Stuck in Perseverance Rover

Debris is temporarily stopping the rover’s rock-sampling mission.

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The rust-orange surface of Mars, with a large rock next to the wheel of Perseverance.
The ground beneath the Perseverance rover on January 13, 2022, taken by the rover’s SHERLOC camera.
Image: NASA/JPL-Caltech

NASA engineers have executed a plan to clear the Perseverance rover of some debris that has prevented it from properly caching rock samples. The team expects to find out how the clean-up mission went later today.

The issue arose on December 29, when a rock sample from Mars (taken from a rock named Issole) couldn’t be properly moved from the coring bit that drilled into the rock to the long-term sample storage on the rover. The storage is a bit like a lazy Susan; it’s a carousel of samples that rotates every time a sample tube is filled.


The rover sent data to Earth indicating there was more resistance in the sample’s transition than expected, and when the NASA team got images of the issue, they realized that bits of the rock sample had fallen out of the tube and onto the bit carousel. (The rover is capable of functioning despite these jam-ups, but as the machine is still relatively new on Mars, NASA wants to treat the machinery as nicely as they can.) So a plan was drafted to get the little Martian pebbles out of Perseverance’s guts.

Machinery on the Perseverance rover with several orange rocks stuck near an opening.
Debris in Perseverance’s bit carousel, imaged by the rover’s WATSON camera on January 6, 2022.
Image: NASA/JPL-Caltech/MSSS

The team is rotating the bit carousel to shake the pebbles loose. They’re taking data and imagery of Perseverance’s actions as they happen, to track whether debris has actually moved. Last week, the team analyzed and imaged the rocky floor beneath the rover, so if the rover’s subsequent images show additional material on the ground, the team will know the carousel-rotation approach was a success. NASA expects those data and images today.

“If I had to ballpark it, I would estimate we’ll be at our current location another week or so – or even more if we decide to re-sample Issole,” wrote Jennifer Trosper, a project manager at NASA’s Jet Propulsion Laboratory, in a NASA blog post. Trosper noted that the rock was of scientific interest, so it’s likely that Perseverance may give Issole another go.

This pebble problem was not the first blip in Perseverance’s sampling schedule. The rover’s first sampling attempt came up empty, so NASA had to try some alternative methods to actually begin the rock collection. The rover has 43 sample tubes, seven of which have so far been filed. Around the end of the decade, those tubes may be heading to Earth, in the extraordinarily ambitious Mars Sample Return mission.

More: Your Guide to NASA’s Life-Hunting Mars Rover, Perseverance