Ride With Juno as It Flies Past the Solar System’s Biggest Moon and Jupiter

The dark side of Ganymede.
This image of the dark side of Ganymede was obtained by Juno’s Stellar Reference Unit navigation camera during its June 7, 2021, flyby of the moon. (Image: NASA / JPL-Caltech / SwRI)

On June 7, 2021, NASA’s Juno spacecraft flew closer to Jupiter’s ice-encrusted moon Ganymede than any spacecraft in more than two decades. Less than a day later, Juno made its 34th flyby of Jupiter, racing over its roiling atmosphere from pole to pole in less than three hours.

Using the spacecraft’s JunoCam imager, the mission team has put together this animation to provide a “starship captain” point of view of each flyby. Scott Bolton, the principal investigator for Juno from the Southwest Research Institute in San Antonio, said:

“The animation shows just how beautiful deep space exploration can be. The animation is a way for people to imagine exploring our solar system firsthand by seeing what it would be like to be orbiting Jupiter and flying past one of its icy moons. Today, as we approach the exciting prospect of humans being able to visit space in orbit around Earth, this propels our imagination decades into the future, when humans will be visiting the alien worlds in our solar system.”

The 3:30-minute-long animation begins with Juno approaching Ganymede, passing within 645 miles (1,038 kilometers) of the surface at a relative velocity of 41,600 mph (67,000 kph). The imagery shows several of the moon’s dark and light regions (darker regions are believed to result from ice sublimating into the surrounding vacuum, leaving behind darkened residue) as well as the crater Tros, which is among the largest and brightest crater scars on Ganymede.

On June 7, 2021, NASA’s Juno spacecraft flew closer to Jupiter’s ice-encrusted moon Ganymede than any spacecraft in more than two decades. Less than a day later, Juno made its 34th flyby of Jupiter. This animation provides a “starship captain” point of view of each flyby. For both worlds, JunoCam images were orthographically projected onto a digital sphere, and synthetic frames were added between actual images to make the motion appear smoother and provide views of approach and departure for both Ganymede and Jupiter.

It takes just 14 hours and 50 minutes for Juno to travel the 735,000 miles (1.18 million kilometers) between Ganymede and Jupiter, and the viewer is transported to within just 2,100 miles (3,400 kilometers) above Jupiter’s spectacular cloud tops. By that point, Jupiter’s powerful gravity has accelerated the spacecraft to almost 130,000 mph (210,000 kph) relative to the planet.

Among the Jovian atmospheric features that can be seen are the circumpolar cyclones at the north pole and five of the gas giant’s “string of pearls” — eight massive storms rotating counterclockwise in the southern hemisphere that appear as white ovals. Using information that Juno has learned from studying Jupiter’s atmosphere, the animation team simulated lightning one might see as we pass over Jupiter’s giant thunderstorms.

This image of the Jovian moon Ganymede was obtained by the JunoCam imager aboard NASA’s Juno spacecraft during its June 7, 2021, flyby of the icy moon.
This image of the Jovian moon Ganymede was obtained by the JunoCam imager aboard NASA’s Juno spacecraft during its June 7, 2021, flyby of the icy moon. At the time of closest approach, Juno was within 645 miles (1,038 kilometers) of its surface — closer to Jupiter’s largest moon than any other spacecraft has come in more than two decades. This image is a preliminary product — Ganymede as seen through JunoCam’s green filter. Juno is a spin-stabilized spacecraft (with a rotation rate of 2 rpm), and the JunoCam imager has a fixed field of view. To obtain Ganymede images as Juno rotated, the camera acquired a strip at a time as the target passed through its field of view. These image strips were captured separately through the red, green, and blue filters. To generate the final image product, the strips must be stitched together and colors aligned. At the time this preliminary image was generated, the “spice kernels” (navigation and other ancillary information providing precision observation geometry) necessary to properly map-project the imagery were not available. The red, and blue filtered image strips were also not available. When the final spice kernel data and images from the two filters are incorporated, the images seams (most prevalent on the lower right of the sphere) will disappear and a complete color image will be generated. (Image: via NASA / JPL-Caltech / SwRI / MSSS)

The camera’s point of view for this time-lapse animation was generated by citizen scientist Gerald Eichstädt, using composite images of Ganymede and Jupiter. For both worlds, JunoCam images were orthographically projected onto a digital sphere and used to create the flyby animation. Synthetic frames were added to provide views of approach and departure for both Ganymede and Jupiter.

As planned, the gravitational pull of the giant moon has affected Juno’s orbit, resulting in the reduction of its orbital period from 53 days to 43 days. The next flyby of Jupiter, the 35th of the mission, is scheduled for July 21.

Provided by: NASA [Note: Materials may be edited for content and length.]

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  • Troy Oakes

    Troy was born and raised in Australia and has always wanted to know why and how things work, which led him to his love for science. He is a professional photographer and enjoys taking pictures of Australia's beautiful landscapes. He is also a professional storm chaser where he currently lives in Hervey Bay, Australia.

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