How Perseverance handles its pebble problem

The Perseverance rover, which is currently exploring Mars’ Jezero crater, encountered a challenge while collecting samples from the planet. It recently attempted to collect a sample from a rock called Issole, but sensors detected an anomaly during the collection process and the rover had to suspend its activities.

“This is only the 6th time in human history that a sample has been extracted from a rock on a planet other than Earth, so when we see something abnormal happening, we slow down” , wrote Louise Jandura, lead engineer for sampling and caching. at NASA/JPL, in a update.

The team discovered that the problem occurred in a part of the sample collection process called Coring Bit Dropoff. This is after the rover has drilled into the rock and taken a sample. The drill and sample tube must then be guided from the drill to the end of the rover’s robotic arm and into its carousel, inside the rover’s frame. During this movement, upon placing the sample in the carousel, the rover’s sensors detected more resistance than expected and stopped for investigation.

When the team looked at the footage from the carousel, they saw that there were pebbles inside that likely fell out of the sample tube. It’s those pebbles that prevent the sample tube from fitting snugly into the carousel, so they started their next task of cleaning up that debris. This involved using the robotic arm to pour the sample onto the ground.

“I imagine your next question is, ‘Why are you emptying the contents of the sample tube? “” Jennifer Trosper, project manager at NASA’s Jet Propulsion Laboratory, wrote in another update. “The answer is that at this time we are uncertain how much core rock continues to reside in tube 261. And while this rock will never make it to my vacation map list, the The science team seems to be really enjoying it, so if our plans go well with our pebble attenuation (see below), we might very well attempt to dig “Issole” (the rock this sample was taken from) again ).”

Next, the team will run tests by spinning the carousel twice and seeing if that moves or dislodges the pebbles. “We expect data and images from these two spin tests to be sent to Earth by next Tuesday, January 18,” Trosper wrote. “From there, we will analyze and refine our plans. If I had to make a rough calculation, I would estimate that we will be at our current location in about a week or more if we decide to resample Issole.