Leonard David's INSIDE OUTER SPACE

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

NASA’s Curiosity Mars rover is now performing Sol 3087 tasks.

Last week, Curiosity circled the base of “Mont Mercou” and has 3-D profiled the large outcrop, reports Catherine O’Connell-Cooper, a planetary geologist at the University of New Brunswick; Fredericton, New Brunswick, Canada. The robot began climbing up the side of the nearly 20-feet (6-meters) high outcrop.

Curiosity Front Hazard Avoidance Camera Right B photo taken on Sol 3086, April 11, 2021.
Credit: NASA/JPL-Caltech

“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,” O’Connell-Cooper adds.

Dust Removal Tool apparently in action, shown by circular patch. Curiosity Mars Hand Lens Imager photo produced on Sol 3086, April 11, 2021.
Credit: NASA/JPL-Caltech/MSSS

Paired drill sites

The plan calls for drilling at that spot, 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,” O’Connell-Cooper points out.

Curiosity Left B Navigation Camera photo taken on Sol 3086, April 11, 2021.
Credit: NASA/JPL-Caltech

As part of any drill campaign, researchers carefully investigate an area, sometimes finding the most “representative” drill site to reflect the bulk composition of the outcrop.

Choosing a drill target

“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,” O’Connell-Cooper notes. “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!”

Curiosity Front Hazard Avoidance Camera Right B photo acquired on Sol 3086, April 11, 2021.
Credit: NASA/JPL-Caltech

A Curiosity target last Wednesday labeled “Puymangou” may be the remnant of the same type of dark veins scientists see in the rover’s

current workspace. New targets are being appraised to aid the next drilling session, but are also safe for the Alpha Particle X-Ray Spectrometer (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,” O’Connell-Cooper says. “Eventually, we decided on a flat bedrock ‘Peyrignac’ which we can brush with our DRT [Dust Removal Tool] centered on the nodule-poor bedrock, to analyze with APXS and MAHLI [Mars Hand Lens Imager].

Curiosity Left B Navigation Camera photo taken on Sol 3086, April 11, 2021.
Credit: NASA/JPL-Caltech

Nodule-rich bedrock

“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,” reports O’Connell-Cooper.

The plan calls for driving further onto the top of Mont Mercou on the second sol of the plan (Sols 3085-3087) “and then Mastcam will image our terrain, with the aim of refining our drill target selection in the next plan, on Monday,” O’Connell-Cooper concludes. “With luck, we might even be drilling again by this time next week!”