ESA’s Juice mission prepares to journey to Jupiter

ESA's spacecraft Juice (JUpiter ICy moons Explorer) is getting ready for its eigh-year journey to Jupiter, due to begin on 13 April. 

The 6.6-billion-kilometre journey has been supported by British scientists, as well as the UK Space Agency, which has provided £9m of funding for the £1.4bn project.

Juice will be heading towards the solar system’s largest planet carrying 10 scientific instruments, in what is the ESA's biggest deep-space mission yet.

“Juice will take us to a part of the solar system that we know relatively little about, to study Jupiter, our largest planet, and to investigate whether some of its icy moons are home to conditions that could support life,” said Dr Caroline Harper, head of space science at the UK Space Agency.

One of these instruments in a magnetometer, known as J-MAG, which will measure the characteristics of the magnetic fields of Jupiter and its largest moon, Ganymede. Its development was led by experts from Imperial College London.

The instrument will also play a key role in detecting moving salts in the oceans beneath the icy crusts of Ganymede as well as exploring Jupiter’s other moons, Europa and Callisto, to analyse whether the oceans could hold the conditions for life.

“With our instrument’s measurements, we are almost looking inside these worlds," said Imperial College London Professor Michele Dougherty. “What we’re doing however is extremely difficult, as the signals we’re trying to detect are extremely small.

“It’s like trying to find lots of needles in a haystack, and those needles are changing shape and colour all the time. But we think the results are going to be spectacular.”

As well as J-MAG, Leicester’s scientists will also collaborate with other experts on two other instruments on Juice: MAJIS (the Moons and Jupiter Imaging Spectrometer) – which will observe cloud features and atmospheric constituents on Jupiter; and UVS (UV imaging spectrograph) – which will characterise the composition and dynamics of the exospheres of the icy moons.

Meanwhile, UCL’s Mullard Space Science Laboratory (MSSL) has provided particle detectors for Juice’s PEP (Particle Environment Package) instrument, which will gather data on “the ‘soup’ of ions, electrons, and atoms surrounding Jupiter and its moons”.

“This data will help us, for instance, to understand how particles around Jupiter reach such high energies – energies that could be fatal for an astronaut," said Professor Geraint Jones, of MSSL and a co-investigator on the PEP instrument. “We are excited that the mission will shed new light on worlds that could potentially host life.”

Juice has been built to withstand harsh radiation and extreme conditions, ranging from 250ºC around Venus to minus 230°C near Jupiter. Due to these extreme temperatures, sensitive electronics are protected inside a pair of lead-lined vaults within the body of the spacecraft.

Professor Emma Bunce, director of the Institute for Space at the University of Leicester, added: “After many years of hard work from science, engineering, and industry teams, we are so excited that the Juice mission is finally ready to launch and start its long journey to the Jupiter system.

“We will patiently await the incredible data that we expect to receive from 2031, and we are confident that it will absolutely be worth the wait.”

The spacecraft is due to launch on 13 April from the European Spaceport in Kourou, French Guiana. Juice will lift off onboard an Ariane 5 rocket at 1.15pm UK time, before separating from the rocket after about half an hour.

The launch is particularly challenging, as the scientists will need to ensure that both Venus and Earth are in the optimal position for Juice to take advantage of its gravitational pull to slingshot towards Jupiter.

“We have to use planets – Earth and Venus – just to get to Jupiter," said Justin Byrne, head of science for Airbus and the mission’s lead contractor. “We will minimise the amount of fuel we need to use by using gravitational support.”

The probe is expected to arrive at its destination in 2031, and spend three years making detailed studies of Jupiter and three of its largest moons, Ganymede, Europa and Callisto.

Once the spacecraft runs out of fuel, Juice will perform a controlled crash into Ganymede, marking the end of its useful life.

In August, Nasa’s James Webb Space Telescope captured pictures of Jupiter that provide unprecedented detail of the planet’s inner life.

In 2011, Nasa launched Juno, a spacecraft tasked with the explicit mission of closely studying Jupiter and its moons. It finally reached the planet in 2016 after a gruelling five-year, 1.4-billion-mile trip, and it has since been unlocking mysteries surrounding the planet and its three moons.