NASA’s Perseverance Mars rover runs into another snag: pebbles

NASA’s Perseverance Mars rover has run into another snag on its mission to find evidence of ancient microbial life

In continuing to collect Martian rock and regolith samples, which will eventually return to Earth, the rover encountered a “new challenge.” 


“Seems some pebble-sized debris is obstructing my robotic arm from handing off the tube for sealing/storage,” the Perseverance team tweeted earlier this month

Now, NASA’s Mars 2020 mission team says it has a plan to deal with the obstruction from the rover’s bit carousel: operational sequences developed and tested over the previous weekend and last week.

“With terrestrial experimentation complete, we have begun executing our mitigation strategy on Mars,” Jennifer Trosper, the project manager at NASA’s Jet Propulsion Laboratory (JPL), wrote Friday. “On Jan. 12 we did a detailed image survey of the ground below Perseverance. This was done so we would have a good idea what rocks and pebbles already exist down there before some more – from our bit carousel – join them in the not-so-distant future. “

With the imaging, the team embarked on a maneuver with the robotic arm she “never imagined we would perform – ever.”

The contents of its latest cored-rock sample – the sixth rock core – will be returned to the surface of Mars in what Trosper called a “fairly straightforward process.” 


The team sent commands up to the rover’s robotic arm on Thursday and Friday.

“I imagine your next question is, ‘Why are you dumping out the contents of the sample tube?’ The answer is that, at present, we are not certain how much cored rock continues to reside in Tube 261. And while this rock will never make my holiday card list, the science team really seems to like it. So if our plans go well with our pebble mitigation (see below), we may very well attempt to core ‘Issole’ (the rock from which this sample was taken) again,” she continued. 

Further commands were to be sent Friday to order the rover to do two rotation tests of the bit carousel that will execute this weekend. 

“Our expectations are that these rotations – and any subsequent pebble movement – will help guide our team, providing them the necessary information on how to proceed. Still, to be thorough, we are also commanding the rover to take a second set of under-chassis images, just in case one or more pebbles happen to pop free,” Trosper continued. 


She said the team expects the imagery and data from the two tests to be sent to Earth by Jan. 18.

“The Perseverance team is exploring every facet of the issue to ensure that we not only get rid of this rocky debris but also prevent a similar reoccurrence during future sampling. Essentially, we are leaving no rock unturned in the pursuit of these four pebbles,” Trosper concluded.

Perseverance also ran into an issue during its first sampling attempt in August.

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