NASA's Curiosity rover recorded two time-lapse videos on Mars, showing its shadow moving across the Martian terrain. The videos, shot while communications were limited, highlight the technical aspects of the rover's cameras and provide insight into Curiosity's ongoing missions and discoveries.
Video captured by the rover shows Curiosity's shadow moving across the Martian surface during the 12 hours it stayed.
When NASA's Curiosity Mars rover is not moving, it serves well as a sundial, as can be seen in two black-and-white videos recorded and sent back by the rover on November 8, the 4,002nd Martian day of the Curiosity rover's mission. The rover used black-and-white hazard avoidance cameras (Hazcams) to capture its shadow moving across the Martian surface.
The instructions to record the video were part of the last set of instructions transmitted to Curiosity before the onset of Martian solar conjunction, the period when the Sun is between Earth and Mars. During this time, the mission team will suspend sending commands to the Mars spacecraft for several weeks because plasma from the sun can interfere with radio communications. (The missions didn't completely lose contact: they still sent regular health check messages back over the radio throughout the rendezvous).
Rover pilots often rely on Curiosity's Hazcam to spot rocks, slopes and other hazards that might pose a risk of crossing. But because the rover's other activities were intentionally curtailed before rendezvous, the team decided to use the hazard camera to record 12 hours of snapshots for the first time, hoping to capture clouds or dust that would reveal more about Martian weather.
When the images were combined and beamed back to Earth, the scientists didn't see any weather of note, but their composite pair of 25-frame videos captured the passage of time. The video, which stretches from 5:30 a.m. to 5:30 p.m. local time, shows Curiosity's silhouette changing as the day progresses from morning to afternoon to evening.
The first video shows a front-end Hazcam image extending southeast along Gediz Vallis (a valley in Mount Sharp). Curiosity has been climbing to the base of the 3-mile-high (5-kilometer-high) mountain in Gale Crater since 2014.
As the sky brightens at sunrise, the shadow of the rover's 7-foot (2-meter) robotic arm moves to the left, and Curiosity's front wheels emerge from the darkness on either side of the frame. Also visible on the left is a circular calibration target mounted on the arm's shoulder. Engineers used the target to test the accuracy of the Alpha Particle X-ray Spectrometer, an instrument used to detect chemical elements on the surface of Mars.
In daylight, the front-facing Hazcam's automatic exposure algorithm determines an exposure time of about one-third of a second. At night, the exposure time increases to over a minute, causing the typical "hot pixel" noise on the sensor that appears as white snowflakes on the final image.
The second video shows a rear Hazcam view looking northwest from the slopes of Mount Sharp to the floor of Gale Crater. The rover's right rear wheel and the shadow of Curiosity's powertrain are clearly visible. The small black dot that appears on the left in the middle of the video (frame 17) is the result of cosmic rays hitting the camera sensor. Likewise, the bright flashes of light and other noise at the end of the video are the result of heat from the spacecraft's power system affecting the Hazcam image sensors.
The images were reprojected to correct for Hazcam's wide-angle lens. The spots on the image, especially noticeable in the rear camera video, are caused by 11 years of Martian dust that has deposited on the lens.
Curiosity was built by NASA's Jet Propulsion Laboratory, which is managed by the California Institute of Technology in Pasadena, California. JPL is leading the mission on behalf of NASA's Science Mission Directorate in Washington.
Compiled source: ScitechDaily