It’s time for JUICE to go to work. The European Space Agency’s Jupiter ICy satellite explorer was launched yesterday on an Ariane 5 rocket, following his eight-year journey into the Jupiter system to study three of the largest moons in the entire solar system: Europa, Ganymede and Callisto. It has started.
With NASA’s Europa Clipper, which will launch in October 2024 but arrive at its destination a year earlier than JUICE, the mission will get the first close-ups of Jupiter’s icy moons. NASA’s Galileo probe I visited Gas Giant from 1995-2003.
“As a result of the Galileo mission, we learned that Europa has a subsurface ocean. Emily Martin, a research geologist at the Center for Earth and Planetary Studies at the Smithsonian National Air and Space Museum. Galileo’s discovery ignited interest in so-called “sea worlds,” where liquid water lies beneath thick surface ice and may be the best place to look for alien life in our solar system. Ganymede and Callisto are also probably sea worlds.
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Galileo captured several images of the lesser-known brothers, but was unable to analyze the surface as originally planned. The spacecraft was crippled from the start, as the high-gain antennas needed to send back the massive amount of data could not be fully deployed. As a result, when JUICE arrives at Jupiter in his 2031 year, the first truly high-resolution study of Ganymede and Callisto will begin, supplemented by data on Europa collected by his Clipper. JUICE will use laser altimeters to create detailed topographic maps of all three of her satellites, and magnetic and gravitational field measurements along with radar to study their internal structure.
“Galileo did reconnaissance,” says Martin.
Is there water on Jupiter’s moons?
If people know of one moon of Jupiter, it’s probably Europa. The icy moon’s subsurface ocean has been the focus of science fiction books and movies. But Martin is particularly excited about what his JUICE will find in his Callisto. He is Jupiter’s second largest moon, orbiting further than Europa and Ganymede. It appears to be geologically inactive and may not have been distinguished. That is, Callisto’s interior is not divided into the crust-mantle-core layers found on other planets and moons.
Despite its modest profile, data from the Galileo mission suggest that Callisto may contain liquid oceans like those of Europa and Ganymede. Understanding how that’s possible, and what the interior of Callisto actually looks like, will help space researchers better understand how all of Jupiter’s moons evolved. It helps to
“In some ways, Callisto is the archetype of Ganymede,” says Martin.
What next for Mars?
It’s not just Callisto’s interior that’s interesting. Scott Shepard, an astronomer at the Carnegie Institute of Science. It is the only large moon to orbit outside the belt of intense radiation trapped in Jupiter’s enormous magnetic field. “Callisto would by far be the first choice if mankind were to build a base on his one of Jupiter’s moons,” says Shepard. “It could be a gateway moon to the outer solar system.”
JUICE will pass by Europa, Callisto, and enter orbit around Ganymede, the largest moon in the solar system. At about 3,270 miles in diameter, it is larger than Mercury, which is 2,578 miles in diameter.
Jeffrey CollinsA professor of geology, physics and astronomy at Wheaton College, he says he’s most excited about the mission’s Ganymede leg. “This is the first time we’ve orbited a world like this, and we know you’ll be amazed at what we discover.”
If there is an ocean of liquid water beneath Ganymede’s frozen crust, how deep is that crust, and is the suspected subsurface ocean a single giant reservoir, or a mantle of ice and rock? Is it composed of a layered liquid? JUICE will be the first mission to give scientists real answers to these questions.
“Even if JUICE makes us understand Ganymede like we did Mars 20 to 30 years ago, it’s a big leap from our current knowledge,” says Collins. “This is going to be like rewriting a textbook.”
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The clues JUICE collects from Ganymede and Callisto don’t just apply to Jupiter and its icy moons. According to Martin, they tell us a lot more about what to expect as we look further out into the solar system.
“It contextualizes different kinds of ocean-world systems, and has even broader implications for exoplanetary systems,” she says. If we can understand , we will be ready to understand the planetary systems we continue to discover in other solar systems.”
