Boulder Bonanza! Science and Sampling Makes an attempt on the Onahu Outcrop on Mars

The Mars Perseverance Rover struggled to collect samples from a crumbly, potentially conglomerate rock at the Onahu outcrop, before exploring another location, Stone Man Pass. Meanwhile, the rover continues to analyze nearby boulders and progress towards Jezero’s inner rim, home to the anticipated carbonate-rich “margin unit,” in pursuit of insights into Mars’ geological history.

Recently on Mars, Perseverance wrestled with sampling a crumbly rock and continued the mission’s boulder-bonanza!

Perseverance spent 3 weeks exploring the Onahu outcrop, after having previously performed an abrasion named Ouzel Falls. From this abrasion, scientists saw that the rock is most likely a conglomerate worth sampling, but was also likely to be crumbly.

Mars Perseverance Sol 803 – Left Mastcam-Z Camera: This image, captured by the Mastcam-Z camera, shows our first attempted sample visible in the tube. This image acquired on May 24, 2023 (Sol 803). Credit: NASA/JPL-Caltech/ASU

The team therefore elected to drive and reposition the rover at an angle more conducive to getting rock inside the sample tube (and away from rover parts, given that pebbles in our bit carousel previously caused the team some headaches before they finally dislodged them). The team also added in extra Mastcam-Z imaging of the tube (see image above) to confirm that the rock made it in there before the sample was sealed.

Although rock is visible, only ~1.3 cm of sample was collected, so the team elected to re-attempt sampling on the Ouzel Falls abrasion spot. Unfortunately, this crumbly conglomerate continues to evade the Perseverance mission! Therefore, Perseverance will drive approximately 40 m to a location called Stone Man Pass and assess whether conglomerates of interest for sampling exist there.

Mars Perseverance Sol 788 – WATSON Camera: NASA’s Mars Perseverance rover acquired this image using its SHERLOC WATSON camera, located on the turret at the end of the rover’s robotic arm. This image was acquired on May 9, 2023 (Sol 788). Credit: NASA/JPL-Caltech

In addition to Perseverance’s sampling attempts, the team has been using Mastcam-Z and SuperCam to observe other nearby boulders. These include a rock they’ve named “Crystal Lake” which shows an interesting surface texture and may be composed of two different clast types; and “Milner Pass” which appears to have purple coatings.

Next up, the rover will be making its way toward the “margin unit,” the carbonate-bearing rocks located along the inner rim of Jezero. The previous stop at Echo Creek revealed rocks consistent with the curvilinear unit, and so the scientists are still waiting in anticipation to encounter the margin unit. The margin unit is thought to be related to a regional olivine-and-carbonate-rich unit that spans thousands of square kilometers. Therefore, assessing whether these deposits are similar to the olivine-rich Séítah, or something new, will help the team understand both the history of Jezero and the surrounding area.

Mars 2020 is unique compared to previous rover missions in that, whilst it has the freedom to explore, eventually, Perseverance will rendezvous with the sample return vehicle to hand off our samples for return to Earth. This mission is a marathon, not a sprint, so the team is taking time to enjoy the stops along the way!