When it landed on Mars in February of 2021, the Perseverance rover joined a small armada of robotic explorers working hard to characterize Mars’ environment and atmosphere and determine if it ever supported life. But unlike its predecessors, one of the key objectives of the rover is to obtain samples of Martian soil and rock, which it will leave in a cache for later retrieval by a joint NASA-ESA mission.

This will be the first sample return from Mars, and the analysis of these samples will provide new insight into the geological and environmental evolution of Mars. The first attempt to obtain a sample didn’t go so well, with the sample crumbling before it was placed in the cache. Undeterred, the science team moved onto the next site and prepared to try again. A few days ago, NASA confirmed that the rover succeeded in its second attempt and has the pictures to prove it!

The mission team was notified about the successful retrieval of the core sample on Sept. 1st, after two days of preparation and weeks of driving. To ensure that the retrieval went as planned, the mission team took additional photos of the drill site and the sample tube before transferring the tube into the rover chassis for assessment and processing. This is not standard procedure, but the team insisted on adding this extra step after the rover’s failed in its first attempt.

The first attempt to procure a drill sample took place on August 5th, where the rover’s Sample Caching System (SCS) employed its three robotic elements to drill and procure a sample of Martian rock. The first is the five-jointed robotic arm that can reach up to 2-meters (7 feet) from the rover and carries a large turret with a rotary percussive drill. The second element is the bit carousel, which provides the drill bits and empty sample tubes to the drill.

This same element is also responsible for transferring sample-filled tubes into the rover’s chassis, where they are assessed and processed. The third is the 0.5-meter (1.6-foot) sample handling arm (aka. the “T-Rex Arm”) that is located in the rover’s underbelly and is responsible for moving sample tubes between storage and documentation stations, as well as the bit carousel.

Initially, data sent back from the rover’s percussive drill indicated that it had successfully drilled a core sample. However, hours later, the team was notified by the SCS that the sample tube was empty once it was placed back in the rover’s chassis. It was eventually deduced that the coring sample was too powdery and fell apart between being removed from the ground and put into a tube and stored inside the SCS.

The target for the second sample collection was a large rock the team nicknamed “Rochette,” which is located along a ridgeline known as “Artuby.” This ridgeline is more than 900 meters (984.25 yards) long and borders two geologic units believed to contain the deepest and most ancient layers of exposed bedrock in the Jezero Crater. The data received from the rover on Sept. 1st confirmed that Perseverance had successfully cored a sample from the rock.

This Mastcam-Z image shows a sample of Mars rock inside the sample tube on Sept. 1, 2021, and the same tube after it was cleared. NASA/JPL-Caltech/ASU/MSSS

Ordinarily, the rover’s science team would not obtain additional imagery before sealing and storing a Martian coring sample. However, given what happened during the previous attempt on Aug. 5th, the team decided that extra assurance was necessary. To this end, Perseverance maneuvered the corer, bit, and open end of the sample tube to be imaged by the rover’s Mastcam-Z instrument.

The initial images showed the end of an intact cored rock within the sample tube, but the team decided to inspect the tube again after clearing it. This involves a procedure known as “percuss to ingest,” which vibrates the drill bit to clear the lip of the sample tube of any residual material. Once this was done, the rover took the second set of Mastcam-Z images (seen above). The light was poor in the second one, and
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