Perseverance has a big job to do while roving across Jezero and exploring the Delta Front, which is campaign #2 of the mission. One of the major goals of this mission (and campaign) is searching for evidence of past life, and we know from studying deltas on Earth that fine-grained clay-rich rocks in these environments are some of the best at preserving ancient biomarkers. Biomarkers, or “molecular fossils,” are complex organic molecules created by life and preserved in rock for up to billions of years for certain molecular classes. Towards this goal, Perseverance is drilling core samples that will eventually be returned to Earth where future scientists can analyze them in advanced laboratories, using instruments and techniques capable of identifying and extracting organics, then characterizing their molecular structures in detail. These analyses can help determine whether any organic molecules contained in Martian delta rocks are biomarkers or abiotic (non-biological) organics. Sample return is one of the most important strategies this mission is using to search for evidence of past life in Jezero!
Perseverance and the science and engineering teams are working together to pick the right rocks to core, using a suite of onboard instruments to understand mineralogy, elemental distributions, and detect whether organic molecules are present. This process helps triage samples and predict which ones are most likely to contain potential biomarkers. However, choosing and collecting samples is often challenging, and there is always a tradeoff between scientific interest and engineering constraints. Sometimes, fragile materials fracture, crack, or even crumble during the abrasion and coring process, and other rocks have tricky shapes and angles that make drilling difficult or impossible.
Last week, the team hoped to sample Betty’s Rock, a layered rock made up of alternating coarse-grained and fine-grained materials. It appears that Betty’s Rock came from the Rocky Top outcrop many meters above, breaking free and landing near the bottom of the delta front at some point in the past. Although this target was intriguing, the team soon found that its jagged layers and awkward shape prevented the rover from safely maneuvering its arm and placing the corer on the target to abrade and drill. However, all is not lost! After looking around the workspace, the team spotted Skinner Ridge Rock, a low-lying rock that looks very similar to Betty’s Rock, but with a much more approachable shape for potential abrasion and coring. We plan to bump the rover over to this target, study its composition, and hopefully collect a sample. This process will take several sols (days on Mars) to complete, but we all have our fingers crossed for success. Exploring Mars can be a lot of work, but it’s called Perseverance for a reason!