20 August 2018

Sol 2147: SAM EGA on the Stoer Sample!

Posted by Ryan Anderson

With the successful drilling of the Stoer target two weeks ago, Curiosity has been busy characterizing the surrounding terrain using its remote instrument package, performing contact science in the immediate vicinity to understand the composition and physical nature of the bedrock, and also performing power-intensive lab-quality analyses of the Stoer sample using its onboard analytical instruments. In today’s plan, Curiosity will perform an evolved gas analysis (EGA) on the Stoer sample using the Sample Analysis at Mars (SAM) instrument. EGA analyses are critical towards understanding the volatiles and organic molecules that may be present within the sample. SAM will heat the Stoer sample to very high temperatures, more than 900 degrees Celsius, and will measure the composition of gases (including H2O, CO2, and SO4) that bake out of the sample at each temperature increment. Many mineral species, including clays, sulfates, and carbonates, have diagnostic temperatures at which the volatile compounds are baked away. This EGA analysis will directly complement other chemical (e.g., APXS, ChemCam) and mineralogical (e.g., CheMin) analyses of the Stoer sample, and will be extremely important in understanding how the composition of this sample compares to others along the rover’s traverse.

Before these SAM EGA activities, however, there is enough spare power for the science team to conduct approximately one hour of targeted remote science. The activities added to this science block include several Mastcam images to monitor changes in small ripple patches near the rover, imaging of the rover deck to monitor the accumulation of wind-blown sand and dust, and multispectral images of two targets. The first multispectral imaging target is named ‘Pentland Hills,’ which is a patch of broken rocks that was run over by Curiosity (within the wheel tracks of the displayed Navcam image. The second multispectral target is named ‘Strontian,’ which is an exposure of grey rocks in front of the rover. In addition to a few minutes of environmental analyses (including a dust devil survey), the bulk of the science block will be dedicated to a ChemCam passive observation calibration sequence. This sequence will ensure that ChemCam passive spectra can be accurately calibrated even as the martian dust storm continues to evolve over time.

Once these science activities are completed (by approximately local noon), Curiosity will spend the majority of the afternoon napping and saving power before the SAM EGA analyses run overnight from just before 11pm until just after 5am. After a mid-morning nap, Curiosity will be ready to go to perform additional science activities in tomorrow’s plan!

Written by Mark Salvatore, Planetary Geologist at University of Michigan