Written by Lucy Thompson, Senior Research Scientist, University of New Brunswick, Canada
Earth planning date: Friday, July 27, 2026
As an APXS uplink lead and strategic planner, I have the privilege of working with the rover engineers most days that I am on operations. The APXS instrument measures the chemistry of rocks, unconsolidated materials and the atmosphere, and is situated on the end of Curiosity’s robotic arm. This means that any target of interest that we wish to analyze has to be safe to deploy the arm, APXS, and MAHLI (the closeup imager) to. We therefore rely on the rover engineers for their assessment and to sequence the arm moves to place us safely on the targets. Recently, our workspaces have been dusty with varied relief, but the rover engineers have successfully found areas that they have been able to brush and deploy APXS and MAHLI. This week was no exception, despite some of our workspaces appearing less than ideal upon initial observation. The team managed to find rock targets of interest (x5), which the rover engineers were able to safely place the arm on and brush so that we could analyze them with APXS and MAHLI. This ensures that we acquire high-quality compositional data and images as we continue our ascent of Mount Sharp, through rock layers of varying tone and texture, tracking potential changes in chemistry, and the depositional and alteration environment.
The rover engineers are also responsible for safely driving Curiosity to the areas of interest identified by the science team. They must assess the terrain for potential hazards such as large resistant blocks that could damage the rover wheels, sand/soil patches where we could get stuck, and high slopes that the rover could slip on. Despite unexpected damage to the wheels early in the mission and getting a little bogged down in some soil/sand just as we started to climb Mount Sharp, the engineers have successfully navigated us safely along more than 23 miles (37 kilometers) of drive distance and more than 4,400 feet (about 1.35 kilometers) of elevation gain. We recently requested to drive to specific locations in order to image what the team thinks could be an erosional surface within the Mg-sulfate/carbonate-bearing unit (see the image accompanying this post). Of course, the engineers were able to accommodate our desires, with the first stop crossed off in Monday’s plan, and the drive that is being planned this weekend taking us toward the next stop.
The rover engineers also ensure that our drilling activities execute safely and successfully, and are responsible for sequencing the arm motion required to deliver the drilled samples to our internal CheMin and SAM instruments. This required completely reconfiguring how we drill after a motor failed back in 2016, with extensive behind-the-scenes work at JPL for nearly a year and a half before we resumed. Curiosity has since drilled more than 20 rock targets.
So, thanks to the rover engineers and all the engineers and scientists on Curiosity’s team, we have had another full week of activities at Gale crater. We continue to track the chemistry, textures, tone and sedimentary structures of the sulfate/carbonate unit as we climb Mount Sharp and get ever closer to the Yardang unit with APXS, ChemCam, MAHLI and Mastcam. Curiosity continues to also monitor the local environment within Gale and the atmosphere in general.
