The images from a historic flying city of our solar system’s largest moon are beginning to roll in.
On Monday (June 7), NASA’s Juno probe zoomed in at just 1,038 kilometers from Jupiter’s huge satellite Ganymede, which is larger than the planet Mercury. It was the closest a probe had come to Ganymede since May 2000, when NASA’s Galileo spacecraft arrived within about 1,000 km of the moon’s icy surface.
It takes some time to receive and process all the data from Monday’s meeting, but we’re already getting a taste: The first two photos from flyby have come down to Earth, and NASA published them online Tuesday (June 8).
Related: Images of Ganymede, Jupiter’s largest moon
One of the pictures, taken off JunoCam instrument, shows almost an entire side of the crater-bound Ganymede, which is believed to have a giant sea of liquid water beneath its ice shell. (The ocean is probably sandwiched between two layers of ice, so it is not as astrobiologically interesting as the ocean floor under the Jupiter moon Europe and the Saturn satellite Enceladus. These other buried oceans are in contact with the stony interiors of their moons, allowing for a number of complex chemical reactions, scientists say.
The JunoCam image, which has a resolution of approx. 1 km pr. Pixel, was taken using the instrument’s green filter. The image is black and white, but the mission team will be able to create a color portrait when the versions taken with JunoCam’s red and blue filters come down, NASA officials said.
The second image comes with permission from the Stellar Reference Unit, a black and white camera that Juno uses for navigation. This image, which has a resolution of 0.6 to 0.9 km per Pixel, shows the side of Ganymede facing the sun, which is dimly lit by light jumping over Jupiter.
“The conditions in which we collected the dark side image of Ganymede were ideal for a low-light camera like our Stellar Reference Unit,” said Heidi Becker, Juno’s radiation monitoring line at NASA’s Jet Propulsion Laboratory in Southern California. said in a statement.
“So this is a different part of the surface than seen by JunoCam in direct sunlight,” Becker said. “It’s going to be fun to see what the two teams can put together.”
Launched in August 2011, Juno arrived in Jupiter in July 2016. The solar-powered probe studies Jupiter’s composition, internal structure and magnetic and gravitational fields and collects data to help scientists better understand how Jupiter and our solar system are formed and evolved.
Juno occasionally turns his sharp eyes to other objects in the Jovian system – such as Ganymede, which is 3,273 kilometers wide (5,268 km). Observations made during Monday’s flight city could reveal key insights into, among other things, the moon’s composition, ice shell and radiation environment, NASA officials said.
Such data can help inform and guide future missions to the Jupiter system, including Europe’s Jupiter Icy Moons Explorer (JUICE) spacecraft scheduled to launch in 2022 to study Ganymede and other Galilean moons Europe and Callisto up close.
Mike Wall is the author of “Out there“(Grand Central Publishing, 2018; illustrated by Karl Tate), a book about the search for alien life. Follow him on Twitter @michaeldwall. Follow us on Twitter @Spacedotcom or Facebook.