Juice: The European Space Agency’s mission to find alien life on Jupiter’s moons

A space mission with a name like no other is about to embark on a journey to find alien life on the moons of Jupiter.

Juice (that’s short for Jupiter Icy Moons Explorer) is a European Space Agency (ESA) venture to make unprecedentedly detailed observations of the gas giant.

It will include searching its icy moons – Ganymede, Callisto, and Europa, which each have their own oceans – to find out whether they could have supported life, and maybe if they still do.

As the final countdown to launch approaches, here’s everything you need to know about humanity’s latest quest to explore the stars.

When and where is the launch?

Juice is planned to launch at 1.15pm UK time on Thursday.

It will be fired skyward aboard an Ariane 5 rocket from the ESA’s spaceport in Kourou, French Guiana.

So yes, it’s not actually launching from Europe, but rather a French territory on the north coast of South America.

A livestream of the launch will begin around half an hour before the blast-off time, so you can get swept up in the excitement before the real action begins.

If the timings go to plan, Juice will separate from the upper stage of Ariane 5 at 1.42pm UK time, and should send its first signal down to the Earth’s surface by 1.51pm, allowing mission crews to take control of the craft.

How long will the mission go on for?

Quite some time, you certainly won’t be tuning in for a livestream of the entire mission.

Juice’s total cruise time will be eight years and include flybys of Earth and Venus on its way to Jupiter, where it will make close encounters with its three moons.

They will be observed using remote sensing and geophysical tools, as well as equipment on the craft.

Jupiter itself will also be closely examined, with astronomers hoping that knowledge gained about its complex magnetic, radiation, and plasma environment will help inform studies of other gas giants.

One of which is Saturn, another gas giant with moons boasting oceans that could support life. Such worlds have the greatest known reserves of water outside Earth, and Juice is the first mission to explore them.

The ESA will be assisted in its work by NASA, and the space agencies of Japan and Israel.

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What do we know about the spacecraft and rocket?

Every space launch is something of an engineering miracle, but Ariane 5 is relatively standard so far as rockets go.

Described by the ESA as “the workhorse” of its access to space, it’s not to the level of NASA’s record-breaking, multibillion-dollar Space Launch System powering the Artemis programme.

That said, Ariane 5 did carry NASA’s James Webb Space Telescope into orbit in December 2021.

The ESA has launched more than 100 Ariane 5 rockets, and it will finally be retired next year. You can probably guess what its successor is called.

Juice is pretty much top of the line so far as probes go – and it cost £1.4bn.

Much of that went towards making sure solar power can work in a section of space that enjoys just 3% of the illumination Earth gets from the sun. Earth is about 93 million miles from the sun, Jupiter isn’t far off 500 million.

It is, as Juice spacecraft manager Christian Erd described it…

‘A faraway, dark place’

The Juice mission’s intrepid team of engineers were tasked with developing capable solar cells that could operate in super dark conditions.

The result were ones with a “triple junction” design – that means three layers of cells are placed on top of each other, generating power from different wavelengths of sunlight.

It makes them more efficient than those made for previous missions, but the task at hand was still a tough one.

Solar cell engineer Carsten Baur said the solar power received around Jupiter was “like going indoors” compared to what you would get near Earth.

Speaking of going indoors, Juice needs to be covered in so many solar cells (24,000) that there are enough to fill an average-sized living room.

In a vote of confidence, NASA is using them for its own Europa Clipper mission to Jupiter in 2024.

It’s due to arrive at Jupiter by 2030, beating Juice by a year thanks to taking a shorter route.

Juice will end its mission by going into orbit around Ganymede, marking the first time a spacecraft has ever been stationed at a moon other than Earth’s. It’s expected to happen in 2034.

Indeed, this spacecraft will be making history for a long time to come.