MISSION UPDATES | April 9, 2021

Sols 3085-3087: Moving Forward on 'Mont Mercou'

Written by Catherine O'Connell-Cooper, Planetary Geologist at University of New Brunswick
Mount Sharp as seen by the Curiosity

The top of “Mont Mercou” in front of the rover is visible in this image taken by the Left Navigation Camera on board NASA’s Mars rover Curiosity on Sol 3083. Mount Sharp is the white hill in the distance. Credit: NASA/JPL-Caltech. Download image ›

Last week, Curiosity circled the base of "Mont Mercou," taking advantage of this rare opportunity to 3-D profile a large prominent outcrop, before beginning the climb up the side of this 6-meter-high outcrop. For today’s planning, we found ourselves almost at the top, with a beautiful expanse of bedrock in our workspace and stunning views of the top of "Mount Sharp" off in the distance (the white hill in the above image). Our plan is to drill up here, a companion drill to the “Nontron” drill at the base of the outcrop. These paired drill sites (and resulting mineralogical data), combined with the extensive imagery acquired by Mastcam, will go a long way to help us understand the evolution of this outcrop.

As part of any drill campaign, we carefully investigate an area, sometimes finding the most “representative” drill site to reflect the bulk composition of the outcrop. For some of our previous drill locales, bedrock was homogeneous, with little evidence of veining for example, which makes choosing a drill target much easier. Here at Mont Mercou, this is definitely not the case! Bedrock in today’s workspace varied from nodule-rich (small circular or lenticular features) to nodule-poor and contained both white veins (typically calcium sulphate) and more unusual dark toned resistant “fins” of vein material – lots happening here, geologically speaking!

As APXS PUDL (Payload Uplink & Downlink Lead) today, my role was to assess the downlink from our target on Wednesday (“Puymangou,” which may be the remnant of the same type of dark veins we see in our current workspace) and to help pick today’s target. I looked for targets that would aid our drill selection next week but that are also safe for the APXS instrument. Those dark veins look really interesting but the fin-like morphology means that they can pose a danger to APXS if, for example, a pointed edge went up into the sensor. Eventually, we decided on a flat bedrock “Peyrignac” which we can brush with our DRT tool, centered on the nodule-poor bedrock, to analyze with APXS and MAHLI. Typically, DRT targets also have an offset APXS and MAHLI target, 18 mm from the center of the main target. Conveniently, the Peyrignac offset target should end up centered on nodule-rich bedrock, so this will give us a more complete idea of the composition here.

We will drive further onto the top of Mont Mercou on the second sol of this plan, and then Mastcam will image our terrain, with the aim of refining our drill target selection in the next plan, on Monday. With luck, we might even be drilling again by this time next week!