Ganymede doubtless has some particular traits. It isn’t simply Jupiter’s greatest moon, however the greatest in your entire photo voltaic system by far—in regards to the dimension of Mercury and our moon mixed. It harbors about six occasions as a lot liquid water as Earth, however it could possibly be hidden beneath 100 miles of ice, Witasse says. Ganymede’s additionally distinctive in possessing an iron core that generates the moon’s personal magnetic discipline—the one rocky physique within the photo voltaic system to take action, apart from Mercury and Earth. Its magnetic discipline might have originated from its proximity to Jupiter, which might have brought on a tidal flexing of its inside construction.
Juice comes geared up with quite a few instruments for scientists to look at these heavenly our bodies from afar, together with a high-resolution optical digicam known as Janus, a laser altimeter known as GALA to measure Ganymede’s tidal deformation by Jupiter’s gravitational pull, a submillimeter-wave instrument known as SWI that can look at Jupiter’s ambiance, and a magnetometer known as J-Magazine to review the interplay of Jupiter’s and Ganymede’s magnetic fields. “The spacecraft’s full suite of cutting-edge devices makes Juice the following step in science,” says Alessandro Atzei, the mission’s payload system engineer. “We anticipate a whole lot of new findings, together with the composition of the magnetic discipline, the fabric of the moons, and an understanding of the ambiance of Jupiter.”
Atzei additionally highlights the spacecraft’s ice-penetrating radar and its gravity probe, named RIME and 3GM, respectively. The radar will be capable of spot pockets of underground water all the way down to a depth of about 10 kilometers, and it’s in all probability delicate sufficient to detect it beneath Europa’s floor, however not Ganymede’s. The gravity probe might present details about Ganymede’s inside ocean, and it might conclusively decide whether or not Callisto has an ocean deeper beneath floor.
Juice follows a protracted line of area probes to the outer planets. NASA’s Pioneer 10 flew by Jupiter in 1973, and both Voyager spacecraft adopted six years later. The Galileo spacecraft orbited Jupiter for years beginning in 1995, enabling the invention of the moon’s magnetic discipline. Right this moment, NASA’s Juno orbiter remains to be working its prolonged mission—on April 8 it accomplished its fiftieth shut go of Jupiter since 2016. It’s arduous to foretell if Juno will nonetheless be chugging alongside when Juice arrives, however the brand new craft can be constructing on its predecessor’s accomplishments and legacy.
“Our radiometer noticed by way of the ice on Europa and Ganymede for the primary time, and their radar instrument is designed to do this another way,” says Scott Bolton, Juno’s principal investigator and an astronomer on the Southwest Analysis Institute. “Their information set will inform us in order that we will look again and reinterpret Juno information,”
Juno has revealed dramatic views of Jupiter’s mysterious auroras and swirling polar cyclones, and it mapped an odd patch of the planet’s magnetic field nicknamed the Nice Blue Spot. (It’s totally different from the long-lasting red, Earth-sized storm.) Juno’s solar-powered system and its armored vault, which shields delicate electronics from Jovian radiation, proved to be such an efficient design that Juice engineers adopted one thing comparable. There may even be some synergy between Juice and NASA’s upcoming Europa Clipper, an orbiter deliberate to launch subsequent 12 months and arrive in 2030.
When the Galileo probe completed its work, it dove into Jupiter’s depths and burned up within the fuel big’s ambiance. Cassini later did the same, plunging into Saturn in 2017, accumulating a final bit of knowledge—and stopping space trash—whereas finishing its mission in dramatic style. The same destiny awaits Juice, which is able to plummet into Ganymede on the finish of its lifespan, in all probability in 2035 or just a few years later.
The fuel big and its main moons have been objects of human fascination since Galileo Galilei found Ganymede and its sister moons in 1610 and made telescopic observations of Jupiter itself. To this present day, folks scan the night time sky for the planet and for Venus. Now area companies are giving the Jovian system its closest look but. “I believe Jupiter is turning into a marketing campaign goal, like Mars has been for fairly some time,” Bolton says. “It is a planet that has intrigued us for a very long time, however it’s not straightforward to get to. It could be nice to have a number of spacecraft there on the identical time.”