PREVIEW

When NASA's Curiosity Mars rover takes a break from traversing the Martian terrain, it transforms into an effective sundial, capturing its own shadow in two black-and-white videos recorded on November 8, the 4,002nd Martian day of the mission. The rover utilised its black-and-white Hazard-Avoidance Cameras, or Hazcams, to document the shifting silhouette across the Martian surface.

Instructions for recording these videos were included in the final set of commands transmitted to Curiosity just before the commencement of Mars solar conjunction. This period, during which the Sun aligns between Earth and Mars, prompts a temporary halt in sending commands to Mars spacecraft due to potential interference from solar plasma affecting radio communications.

While typically used for hazard detection, the Hazcams were repurposed to capture 12 hours of snapshots during a scaled-back activity phase just before conjunction. The aim was to potentially capture clouds or dust devils, shedding light on Mars' weather patterns.

Upon receiving the images on Earth, scientists did not observe notable weather phenomena. However, they compiled two 25-frame videos depicting the rover's shadow progressing from morning to evening, covering the period from 5:30 a.m. to 5:30 p.m. local time.

The first video, sourced from the front Hazcam, looks southeast along Gediz Vallis, a valley on Mount Sharp. The sunrise sequence reveals the rover's 7-foot (2-meter) robotic arm's shadow shifting to the left, with Curiosity's front wheels emerging from the darkness. A circular calibration target on the robotic arm's shoulder becomes visible, serving as a tool for testing the accuracy of the Alpha Particle X-ray Spectrometer.

The second video showcases the rear Hazcam's perspective, looking northwest down the slopes of Mount Sharp to the floor of Gale Crater. The right rear wheel of the rover and the shadow of its power system are visible. An artifact appearing during the 17th frame results from a cosmic ray hitting the camera sensor, while flashing and noise at the video's end are attributed to the spacecraft's power system affecting the Hazcam's image sensor.