Leonard David's INSIDE OUTER SPACE

This image was taken by the Left Navigation Camera (NavCam) aboard NASA’s Mars rover Curiosity, and captures the bright stones of the “Sheep Creek” target — just above the rover wheel – which strongly resemble elemental sulfur blocks identified earlier in the traverse. This image was taken on Sol 4314, September 24, 2024.
Image credit: NASA/JPL-Caltech

NASA’s Curiosity Mars rover at Gale crater continues onward in its wheeled survey of its surroundings.

Amelie Roberts, a Ph.D. candidate at Imperial College London, reports that the robot is navigating rugged, unforgiving Martian terrain.

Curiosity Right B Navigation Camera image taken on Sol 4317, September 27, 2024.
Image credit: NASA/JPL-Caltech

Roberts said that this landscape challenge was recently underscored by Curiosity’s recent attempt to reach the “Sheep Creek” target.

“We had aimed for small, distant bright rocks, but from 50 meters away (about 164 feet), the limited resolution of our images made it difficult to fine-tune navigation. After an ambitious drive, the rover came agonizingly close — stopping just short of these small bright rocks,” Roberts points out.

Curiosity Mast Camera Right image acquired on Sol 4316, September 26, 2024.
Image credit: NASA/JPL-Caltech/MSSS

Just out of reach

The rocks, with their distinctive rounded and pitted “weathering” pattern, “strongly resemble elemental sulfur blocks that we’ve encountered before. Frustratingly, although the target rocks were right under the front wheel and clearly visible in our navigation cameras, they remained just out of reach of the rover’s arm,” Roberts notes.

Curiosity Left B Navigation Camera photo taken on Sol 4316, September 26, 2024.
Image credit: NASA/JPL-Caltech

While the rover’s arm couldn’t quite reach the bright stones of Sheep Creek, Roberts adds, “we didn’t let that stop us and planned to use other onboard instruments to help us analyze the composition, textures, and context before we move to our next position.”

Curiosity Front Hazard Avoidance Left B Camera image taken on Sol 4316, September 26, 2024.
Image credit: NASA/JPL-Caltech

Promising stones

To find out the composition of the stones of Sheep Creek, the robot’s Chemistry and Camera (ChemCam) observed two promising stones named “Arch Rock” and “Ash Mountain.”

“We’re hoping to see if they have any evidence of elemental sulfur as their appearance suggests,” Roberts explains. “For a closer look at the texture, we will take high-resolution, color images with Mastcam. We also want to look at an interesting transition between light-colored and dark-colored bedrock nearby, which we will cover with more high-resolution, colored images. This transition could give us clues about where the unusual white rocks of Sheep Creek came from and how they formed.”

Curiosity Right B Navigation Camera image taken on Sol 4317, September 27, 2024.
Image credit: NASA/JPL-Caltech

Intriguing white patches

Researchers had their eyes on another bright rock in the area, named “Beryl Lake.”

It had an interesting bright-toned crusty appearance and as investigators could reach it with the rover arm, the Alpha Particle X-Ray Spectrometer (APXS) was used to see its composition and if it had any traces of sulfur.

Curiosity Mars Hand Lens Imager (MAHLI) photo produced on Sol 4312 September 22, 2024.
Image credit: NASA/JPL-Caltech/MSSS

“We took a closer look with our rover hand lens (MAHLI) at a rock called “Aster Lake,” which had intriguing white patches that might be similar to the stones of Sheep Creek,” Roberts reports. “Ultimately, our science goal this plan was to collect data on whether these bright-toned stones had evidence of elemental sulfur and increase our understanding on how they formed.”

Weekend “bump”

Next, the rover was slated to be carefully repositioned to move closer to these interesting targets — a maneuver called a “bump” — so that next plan, set to occur over the weekend, “we’ll be able to get up close and personal with the white stones of Sheep Creek,” says Roberts.

Curiosity Mast Camera (Mastcam) Left image taken on Sol 4312, September 22, 2024.
Image credit: NASA/JPL-Caltech/MSSS

While the rover waits for the weekend plan, Curiosity was set to do “untargeted” science after the drive. This includes using an automated tool called Autonomous Exploration for Gathering Increased Science (AEGIS) – a software suite that permits the robot to autonomously detect and prioritize targets — and zaps them with the ChemCam laser.

“Plus, it’s a good time to record some observations of the modern Martian environment, so we’ll make the most of the time to measure dust levels, take movies that will hopefully capture some dust devils, and look at clouds — if any — in the Martian sky,” Roberts concludes. “We’re looking forward to the weekend plan to hopefully get another chance to do some contact science on targets that may be rich in sulfur!”