European craft to explore Jupiter

Habitability of three icy moons to be examined

A European spacecraft rocketed away Friday on a decadelong quest to explore Jupiter and three of its icy moons that could hold buried oceans.

The journey began with a perfect morning liftoff by Europe’s Ariane rocket from French Guiana on the coast of South America. But there were some tense minutes later as controllers awaited signals from the spacecraft.

When contact finally was confirmed close to an hour into the flight, Mission Control in Germany declared: “The spacecraft is alive!”

It will take the robotic explorer, dubbed Juice, eight years to reach Jupiter, where it will scope out not only the solar system’s biggest planet but also Europa, Callisto and Ganymede. The three ice-encrusted moons are believed to harbor underground oceans, where sea life could exist.

Then, in perhaps the most impressive feat of all, Juice will attempt to go into orbit around Ganymede: No spacecraft has ever orbited a moon other than our own.

“This is a mission that is answering questions of science that are burning to all of us,” said European Space Agency’s director general, Josef Aschbacher after the launch. “Of course, one of these questions is: Is there life out there?”

It can’t find life, “but Juice will be identifying the habitability of these icy moons around Jupiter,” he added.

The spacecraft is taking a long, roundabout route to Jupiter, covering 4 billion miles

It will swoop within 125 miles of Callisto and 250 miles of Europa and Ganymede, completing 35 flybys while circling Jupiter. Then it will hit the brakes to orbit Ganymede, the primary target of the nearly $1.8 billion mission.

Ganymede is not only the solar system’s largest moon — it surpasses Mercury — but has its own magnetic field with dazzling auroras at the poles.

Even more enticing, it’s thought to have an underground ocean holding more water than Earth. Ditto for Europa and its reported geysers, and heavily cratered Callisto, a potential destination for humans given its distance from Jupiter’s debilitating radiation belts, according to Carnegie Institution’s Scott Sheppard, who’s not involved with the Juice mission.

European Space Agency A rocket carrying the robotic explorer Juice takes off Friday from Europe’s spaceport in French Guiana. It will take the robotic explorer eight years to reach Jupiter.