21 May 2017
The rover planners parked us in front of the one slab of outcrop – an island among ripples of sand – we could safely drive to from our Sol 1700 position, setting us up to continue our exploration of the Murray formation.
The outcrop slab exhibited color variations (gray, pink and orange) and patchy white veins, so to capture these variations the science team analyzed multiple spots on the outcrop with MAHLI, APXS, ChemCam and Mastcam. We brushed dust off the target ‘Fern Spring’ with the DRT and analyzed two separate spots within this dust-cleared area with APXS. Getting two closely spaced APXS targets makes it easier to pull apart compositional variations within the outcrop than a single APXS analysis alone. We planned a ChemCam raster over Fern Spring to be able to compare the compositional results from APXS and ChemCam, and a second, similar target, ‘Redfield Hill’ to maximize the amount of data from the bedrock. Another target that got attention from both APXS and ChemCam was ‘Pulpit Ledge’, so named because this gray-toned area of outcrop appeared perched above the rest of the outcrop surface. The gray color of Pulpit Ledge set it apart from the more orange-red color of Fern Spring and Redfield Hill, and the science team hoped to gain insight into why these parts of the outcrop were different in color by looking at these distinct targets. We looked at another gray outcrop area, ‘Broad Cove’, using the passive mode of ChemCam and the multispectral capability of Mastcam. Both these techniques assess the spectrum of light reflected from the target surface, which provides insight into the iron mineralogy of the target. Each APXS target was imaged with MAHLI, to not only help inform APXS of exactly what part of the outcrop they obtained data from, but to look closely at the texture and grain size of the targets. Looking out past the outcrop immediately in front of us, Mastcam acquired small mosaics of two separate areas of dramatically layered Murray formation. Such large, layered blocks make driving through this part of the Murray formation a challenge, but they help the science team understand how the Murray formation rocks were deposited in Gale crater.
Curiosity cast her gaze skyward over the weekend acquiring images and movies seeking clouds and dust devils, and monitoring the amount of dust in the atmosphere. Measurements of dust in the atmosphere not only provide insight into atmospheric behavior, they help the science team decide when to image distant objects such as Vera Rubin Ridge. The more dust in the atmosphere, the harder it is to see such objects. The rover also prepared for an important upcoming atmospheric analysis, a SAM measurement of atmospheric methane.
Written by Michelle Minitti, Planetary Geologist at Framework