Tactical planning started an hour and a half later than usual this morning, because we had to wait for better-illuminated Navcam images of the Ubajara block seen at bottom center in this image: 

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The Rover Planners needed these better images to determine whether the Ubajara target can be brushed using the DRT, and promptly confirmed that they are GO for brushing!  This was good news, because the MSL science team agreed that MAHLI images and APXS chemical data will be useful in deciding whether or not to drill at Ubajara.  So the Sol 3819 plan is focused on contact science, but first Mastcam will acquire stereo mosaics of nearby layered rocks at Chenapau and extended coverage of the arm workspace.  Then ChemCam will sample the elemental chemical composition of a nodular bedrock target named "Buritis" and acquire a long-distance RMI mosaic of the "Kukenan" outcrop.  The Right Mastcam will then document the LIBS spots on Buritis and Navcam will characterize the dust content of the atmosphere toward the north before the arm is deployed to acquire a full suite of MAHLI images of the brushed spot.  The APXS will be placed on and just off the brushed spot for evening integrations.  

On Sol 3820, Mastcam will take a multispectral observation of the brushed spot and Navcam will search for dust devils.  Then ChemCam will get busy, first shooting its laser at the brushed spot, then acquiring passive spectra of the sky, and finally taking a long-distance RMI mosaic of part of the Chenapau hill.  Mastcam will then document the LIBS spots on Ubajara and measure the amount of dust above the rover.  The rover will take a well-earned nap before waking up for an overnight measurement of atmospheric chemistry that should be very helpful in analyzing the ChemCam passive sky spectra.  It was a busy planning day for me as SOWG Chair, and I'm glad that we were able to fit all of these activities into the power-constrained plan!