During the transfer of the bit that contains the sample into the rovers bit carousel (which stores bits and passes tubes to the tube processing hardware inside the rover), our sensing units showed an anomaly. Its when the drill bit, with its sample tube and just-cored sample nestled inside, is assisted out of the percussive drill (at the end of the robotic arm) and into the bit carousel (which is located on the rovers chassis). During processing of previous cored rock samples, the coring bit traveled 5.15 inches (13.1 centimeters) prior to sensing units began to record the kind of resistance (drag) anticipated at very first contact with the carousel structure. These most recent downlinked images validate that inside the bit carousel there are a few pieces of pebble-sized particles. The group is positive that these are fragments of the cored rock that fell out of the sample tube at the time of Coring Bit Dropoff, and that they prevented the bit from seating totally in the bit carousel.
Debris in Perseverances Bit Carousel: Pebble-sized particles can be seen in the bit carousel of NASAs Perseverance Mars rover in this January 7, 2022, image. Credit: NASA/JPL-Caltech/MSSS
On Wednesday, December 29 (sol 306) Perseverance effectively drew out a sample and cored from a Mars rock. During the transfer of the bit that includes the sample into the rovers bit carousel (which shops bits and passes tubes to the tube processing hardware inside the rover), our sensing units suggested an anomaly.
This is just the 6th time in human history a sample has actually been cored from a rock on a world other than Earth, so when we see something anomalous going on, we take it slow. Here is what we know up until now, and what we are doing about it.
Zoomed-in view of the WATSON (Wide Angle Topographic Sensor for Operations and eNgineering) image, highlighting the place of the sample debris. The location within the blue box is approximately 6.5 millimeters squared. Credit: NASA/JPL-Caltech/MSSS
The abnormality happened throughout “Coring Bit Dropoff.” Its when the drill bit, with its sample tube and just-cored sample nestled inside, is assisted out of the percussive drill (at the end of the robotic arm) and into the bit carousel (which lies on the rovers chassis). Throughout processing of previous cored rock samples, the coring bit traveled 5.15 inches (13.1 centimeters) before sensing units began to record the type of resistance (drag) expected at first contact with the carousel structure. This time around the sensor recorded higher resistance than usual at about 0.4 inches (1 centimeter) earlier than expected, and some much higher resistance than anticipated throughout the operation.
The team requested additional information and imagery to make sure correct understanding of the state post anomaly. Because we are currently running through a set of “limited Sols” in which the latency of the information limits the type of activities we can perform on Mars, it has taken about a week to receive the additional diagnostic data needed to understand this abnormality.
Imaging Perseverances Sample: This image reveals the cored-rock sample staying in the sample tube after the drill bit was extracted from Perseverances bit carousel on January 7, 2022. Credit: NASA/JPL-Caltech
Armed with that information set, we sent up a command to draw out the drill bit and sample-filled tube from the bit carousel and undock the robotic arm from the bit carousel. Throughout these activities, a series of hardware images were obtained.
The extraction took place on January 6, 2022, and information was downlinked early in the morning on January 7. These latest downlinked images validate that inside the bit carousel there are a few pieces of pebble-sized debris. The team is confident that these are fragments of the cored rock that fell out of the sample tube at the time of Coring Bit Dropoff, which they prevented the bit from seating entirely in the bit carousel.
The designers of the bit carousel did think about the capability to continue to successfully operate with particles. This is the very first time we are doing a debris removal and we want to take whatever time is required to ensure these pebbles exit in a regulated and organized style. We are going to continue to assess our information sets over the weekend.
One thing weve found is that when the engineering challenge is hundreds of millions of miles away (Mars is presently 215 million miles from Earth), it pays to take your time and be extensive. That when we do strike the unpaved Martian road again, Perseverance sample collection is likewise ready to roll.
Composed by Louise Jandura, Chief Engineer for Sampling & & Caching at NASA/JPL