MISSION UPDATES | November 14, 2019

Sols 2585-2586: What a Butte!

Written by Claire Newman, Atmospheric Scientist at Aeolis Research
Sols 2585-2586: What a Butte!

Curiosity is again at the “Hunda” facies, high up on Central Butte (note that this is pronounced “beaut” not “butt,” unless one wishes to cause much hilarity). At this location, we’re finding a lot of decimeter-scale laminations - sequences of fine layers - near to and underneath the rover. In these layers, target “Kirkcudbrightshire” was chosen as the location for first ChemCam then APXS analysis, the idea being that ChemCam LIBS would remove any dust covering the target before the APXS contact science overnight. A second APXS target “Foggy Moss” was chosen to sample the float rock found here, which was already analyzed using ChemCam in a prior sol. Here ‘float’ refers to the piece of rock having been transported from its original outcrop, and this one might represent the cap rock of the entire butte. More ChemCam LIBS analyses were planned on targets “Kincardineshire,” which may sample the edge of the rock ledge, “Grogsport,” another bedrock target higher in the section (to test how chemistry, especially sulfate content, changes with position), and “Hog Burn,” another float rock which might also represent the capping unit and can be compared with Foggy Moss. Mastcam mosaics and ChemCam documentation images were used to place all of these measurements in context, and the geology side of the plan finished with Mastcam stereo of layers in the outcrop (“Bonny Braes”), as well as a Mastcam context mosaic of additional outcrop, allowing the various mosaics from this location to be linked together (“Bonnie View”). We also planned MAHLI images of Kirkcudbrightshire and Foggy Moss, and a MAHLI ‘dog’s eye’ mosaic of target “Sourhope”; the latter means that the arm will be positioned so MAHLI looks sideways (rather than down) at the target, to get a better view of the laminations within the rocks.

On the environmental side of the plan, we included the usual REMS monitoring of atmospheric and surface temperature, surface pressure, humidity, and UV radiation, plus DAN passive and active monitoring of the subsurface composition, and the ongoing continuous RAD monitoring of energetic particle radiation. We’re in the cloudy season right now, so we added in a Navcam Cloud Altitude Observation which uses observations of clouds and their shadows, plus geometry, to work out cloud heights. This is a valuable piece of information for inferring the vertical structure of the crater’s atmosphere, as cloud height is related to both water abundance and the thermal profile. We also added a Navcam Dust Devil Survey at about 4:20pm local true solar time. This is a few hours later than we expect most dust devils to occur, especially in winter, based on both theory and past observations. However, we’ve observed dust devils this late in the day in other seasons, and it’s important to repeat these surveys at a range of times in every season each year, rather than assuming nothing will change as we move up the slope! Finally, we measured the amount of dust above us and the visibility across the crater at two times of sol using Mastcam, and measured the across-crater visibility at one time of sol with Navcam also.