This image of Ganymede, one of Jupiter’s moons, was taken by NASA’s Juno spacecraft using its JunoCam imager during a flyby on June 7, 2021. This flyby brought Juno closer to Ganymede than any other spacecraft had been in over two decades, at a distance of 645 miles (1,038 kilometers) from the moon’s surface.
The image is a preliminary result, captured through JunoCam’s green filter. Juno is a spin-stabilized spacecraft, rotating at a rate of 2 revolutions per minute, and JunoCam has a fixed field of view. To create this image, the camera took separate strips as Ganymede passed through its field of view, using red, green, and blue filters. These strips need to be stitched together, and colors aligned to produce the final image.
At the time this preliminary image was created, the necessary “spice kernels” (data for precise observation geometry) and the image strips from the red and blue filters were not yet available. When these data are incorporated, the seams in the image will disappear, and a complete, colorful image of Ganymede will be generated.