关于这张图
The shadow of NASA's Ingenuity Mars Helicopter can be seen in this animated GIF composed of images taken by its black-and-white navigation camera during the rotocraft's third flight, on April 25, 2021. The camera, which tracks surface features below the helicopter, takes images at a rate at which the helicopter's blades appear frozen in place, despite making 21 full rotations in-between each image. At full speed, the blades spin at 2,537 rpm. The images are aligned entirely using Ingenuity's on-board position tracking system highlighting the stability and accuracy of the navigation algorithm. …
