A European spacecraft rocketed away Friday on a decade-long quest to explore Jupiter and three of its icy moons that could have buried oceans.

The journey began with a morning liftoff by EuropeB次元官网网址檚 Ariane rocket from French Guiana in South America. ArianespaceB次元官网网址檚 chief executive Stephane Israel called it B次元官网网址渁n absolutely perfect launch.B次元官网网址�

But there were some tense minutes later as controllers waited for signals from the spacecraft nearly an hour into the flight.

When contact was confirmed, European Space AgencyB次元官网网址檚 Bruno Sousa declared from Mission Control in Germany: B次元官网网址淭he spacecraft is alive!B次元官网网址�

It will take the robotic explorer, dubbed Juice, eight years to reach Jupiter, where it will scope out not only the solar systemB次元官网网址檚 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.

With so many moons,B次元官网网址� at last count 95 B次元官网网址� astronomers consider Jupiter a mini solar system of its own, with missions like Juice long overdue.

B次元官网网址淲e are not going to detect life with Juice,B次元官网网址� stressed the European Space AgencyB次元官网网址檚 project scientist, Olivier Witasse.

But learning more about the moons and their potential seas will bring scientists closer to answering the is-there-life-elsewhere question. B次元官网网址淭hat will be really the most interesting aspect of the mission,B次元官网网址� he said.

Juice is taking a long, roundabout route to Jupiter, covering 4 billion miles (6.6 billion kilometers)

It will swoop within 125 miles (200 kilometers) of Callisto and 250 miles (400 kilometers) of Europa and Ganymede, completing 35 flybys while circling Jupiter. Then it will hit the brakes to orbit Ganymede, the primary target of the 1.6 billion-euro mission (nearly $1.8 billion).

Ganymede is not only the solar systemB次元官网网址檚 largest moon B次元官网网址� it surpasses Mercury B次元官网网址� but has its own magnetic field with dazzling auroras at the poles.

Even more enticing, itB次元官网网址檚 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 JupiterB次元官网网址檚 debilitating radiation belts, according to Carnegie InstitutionB次元官网网址檚 Scott Sheppard, whoB次元官网网址檚 not involved with the Juice mission.

B次元官网网址淭he ocean worlds in our solar system are the most likely to have possible life, so these large moons of Jupiter are prime candidates to search,B次元官网网址� said Sheppard, a moon hunter whoB次元官网网址檚 helped discover well over 100 in the outer solar system.

The spacecraft, about the size of a small bus, wonB次元官网网址檛 reach Jupiter until 2031, relying on gravity-assist flybys of Earth and our moon, as well as Venus.

B次元官网网址淭hese things take time B次元官网网址� and they change our world,B次元官网网址� said the Planetary SocietyB次元官网网址檚 chief executive, Bill Nye. The California-based space advocacy group organized a virtual watch party for the launch.

BelgiumB次元官网网址檚 King Philippe and Prince Gabriel, and a pair of astronauts B次元官网网址� FranceB次元官网网址檚 Thomas Pesquet and GermanyB次元官网网址檚 Matthias Maurer B次元官网网址� were among the spectators in French Guiana. ThursdayB次元官网网址檚 launch attempt was nixed by the threat of lightning.

Juice B次元官网网址� short for Jupiter Icy Moons Explorer B次元官网网址� will spend three years buzzing Callisto, Europa and Ganymede. The spacecraft will attempt to enter orbit around Ganymede in late 2034, circling the moon for nearly a year before flight controllers send it crashing down in 2035, later if enough fuel remains.

Europa is especially attractive to scientists hunting for signs of life beyond Earth. Juice will keep its Europa encounters to a minimum, however, because of the intense radiation there so close to Jupiter.

JuiceB次元官网网址檚 sensitive electronics are encased in lead to protect against radiation. The 14,000-pound (6,350-kilogram) spacecraft also is wrapped with thermal blankets B次元官网网址� temperatures near Jupiter hover around minus 380 degrees Fahrenheit (minus 230 degrees Celsius). And its solar panels stretch 88 feet (27 meters) tip to tip to soak in as much sunlight that far from the sun.

Late next year, NASA will send an even more heavily shielded spacecraft to Jupiter, the long-awaited Europa Clipper, which will beat Juice to Jupiter by more than a year because it will launch on SpaceXB次元官网网址檚 mightier rocket. The two spacecraft will team up to study Europa like never before.

NASA has long dominated exploration at Jupiter, beginning with flybys in the 1970s by the twin Pioneers and then Voyagers. Only one spacecraft remains humming at Jupiter: NASAB次元官网网址檚 Juno, which just logged its 50th orbit since 2016.

Europe provided nine of JuiceB次元官网网址檚 science instruments, with NASA supplying just one.

If Juice confirms underground oceans conducive to past or present life, Witasse said the next step will be to send drills to penetrate the icy crusts and maybe even a submarine.

B次元官网网址淲e have to be creative,B次元官网网址� he said. B次元官网网址淲e can still think itB次元官网网址檚 science fiction, but sometimes the science fiction can join the reality.B次元官网网址�

B次元官网网址擬arcia Dunn, The Associated Press

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