Curiosity rover, on a Martian day 4,002, used its Hazard-Avoidance Cameras to capture two 12-hour videos of its shadow. During a communication blackout, it acted as a sundial. Despite no significant weather findings, the footage shows the rover’s silhouette changing from morning to evening, revealing Mars’ unique landscape and lighting conditions.
AT A GLANCE
- Curiosity Rover’s Sundial Role: When stationary on Mars, NASA’s Curiosity rover serves as a sundial, capturing its shadow on the Martian surface during a 12-hour sequence using Hazard-Avoidance Cameras.
- Solar Conjunction Pause: The recording instructions were sent just before Mars entered solar conjunction, a period when Sun interference with radio signals leads to a pause in sending commands to the rover. Communication during this period is limited to health check-ins.
- Hazcams’ Unusual Use: Typically used to identify hazards, the rover’s Hazard-Avoidance Cameras were repurposed to record 12 hours of snapshots, aiming to capture Martian weather phenomena such as clouds or dust devils.
- No Weather Discoveries: Post-conjunction, although no significant weather observations were made, two 25-frame videos were created, documenting the passage of time from sunrise to sunset on Mars.
- Mountain Ascent: The first video looks southeast along Gediz Vallis, a valley on Mount Sharp, where Curiosity has been ascending since 2014. The footage captures the rover’s silhouette, its robotic arm shadow, and the calibration target for the Alpha Particle X-ray Spectrometer.
- Exposure Changes: Throughout the day, the front Hazcam’s exposure changes, capturing brightening skies during sunrise and introducing sensor noise, or “hot pixels,” at nightfall when exposure times increase.
- Wide-Angle Lens Correction: The second video, looking northwest down Mount Sharp, shows the rover’s rear Hazcam view. Cosmic rays and heat effects are evident, and the speckled appearance is due to 11 years of Martian dust on the lens, corrected for wide-angle lenses.
For a brief period in November 2023, NASA’s Curiosity rover on Mars became an unintentional sundial, offering a unique glimpse into the passage of time on the Red Planet. While communication with Earth was limited due to a period of solar conjunction, Curiosity diligently captured its own shadow creeping across the Martian surface for 12 hours straight. This silent vigil resulted in mesmerizing black-and-white videos, showcasing not only the changing light but also revealing details about the rover’s surroundings and even offering insights into Martian dust.
Credit: NASA/JPL-Caltech
A Day in the Life of a Martian Rover:
Curiosity’s shadow dance began on the 4,002nd Martian day, or sol, of its mission. With communication on hold during solar conjunction, the rover’s usual activities were scaled back. This presented an opportunity for the science team to get creative. They instructed Curiosity to use its Hazard-Avoidance Cameras (Hazcams), typically employed for spotting hazards, to capture snapshots every 30 seconds for 12 hours. The hope was to capture fleeting weather phenomena like dust devils or clouds that might provide clues about Martian weather patterns.
While no dramatic weather events graced the footage, the resulting pair of 25-frame videos, spanning from 5:30 a.m. to 5:30 p.m. local Martian time, offered a captivating time-lapse of Curiosity’s day. The videos showcase the rover’s silhouette morphing from its morning posture to its afternoon stance and finally into its long evening shadow.
Two Views, One Story:
The first video, captured by the front Hazcam, gazes southeast along Gediz Vallis, a valley snaking up the slopes of Mount Sharp, Curiosity’s Martian home since 2014. As the sun climbs higher, the 7-foot robotic arm’s shadow stretches to the left, revealing Curiosity’s front wheels emerging from the darkness. A circular calibration target, used to ensure the accuracy of the Alpha Particle X-ray Spectrometer, also comes into view on the arm’s shoulder.
Throughout the day, the front Hazcam’s autoexposure adjusts to the changing light, with exposure times shifting from a third of a second at midday to over a minute by nightfall. This longer exposure, while necessary to capture details in the fading light, introduces “hot pixels,” appearing as white speckles in the final frame, revealing the sensor’s limitations.
The second video, captured by the rear Hazcam, looks northwest down the slopes of Mount Sharp towards the floor of Gale Crater. Here, we see Curiosity’s right rear wheel and the shadow of its power system. A brief glitch midway through the video, a cosmic ray striking the camera sensor, creates a small black artifact. Additionally, the video’s ending exhibits bright flashes and noise, a consequence of the spacecraft’s heat affecting the Hazcam’s sensor.
Beyond the Shadow Play:
These videos, painstakingly reprojected to correct for the Hazcams’ wide-angle lens distortion, hold scientific value beyond their captivating beauty. The speckled appearance, particularly noticeable in the rear-camera footage, is a testament to the 11 years of Martian dust accumulating on the lenses. This accumulation provides valuable data on the rate and composition of Martian dust, offering insights into the planet’s atmospheric dynamics.
Furthermore, the videos offer a detailed look at Curiosity’s surroundings, revealing subtle changes in the terrain and providing context for future scientific investigations. The changing lighting conditions also highlight the texture and composition of the Martian rocks and soil, potentially aiding in understanding the Red Planet’s geological history.
A Silent Witness to Martian Time:
While Curiosity’s shadow play wasn’t the primary objective of the Hazcam recordings, it serendipitously captured the essence of a Martian day on camera. These videos serve as a reminder of the ingenuity and adaptability of robotic explorers, their ability to turn any situation into an opportunity for scientific discovery. As Curiosity continues its ascent up Mount Sharp, its watchful gaze, even during periods of limited communication, promises to unveil further secrets of the Red Planet, one Martian sundial at a time.
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Source(s): SciTech Daily
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