‘Go Ariane 5’ were the last words from commentators as the JUpiter’s ICy Moons Explorer (or JUICE) set to launch from ESA’s satellite-launching system in Kourou, French Guiana, today.

With the final weather check given the go-ahead – meaning no risk of high winds or the lightning that delayed yesterday’s launch – and the irreversible synchronised launch sequence switched on, the Ariane 5 rocket carrying JUICE lifted off at 1:14pm BST on an eight-year mission towards Jupiter.

A "perfect launch"

JUICE satellite launches on Ariane 5 rocket in French Guiana
The JUICE launch in Kourou, French Guiana © Ariane Space

ESA used gravity to ‘slingshot’ JUICE into its mission trajectory, and despite a tense period as we awaited communication from the craft, JUICE has successfully transmitted its first radio signal to a satellite dish in Western Australia.

Otherwise, “it was a perfect launch” said Stéphane Israël, CEO of Arianespace.

So what happened next?

What happened during JUICE launch: 

  • 1:14pm BST After launching on the Ariane 5 rocket – the same type of rocket that launched the James Webb Space Telescope – JUICE successfully set off on its eastern trajectory. Those at the ESA satellite-launching system in Kourou, French Guiana, were able to feel the impact of lift-off.
  • 1:16pm Booster safely separated from the satellite, providing 90 per cent of the flight’s thrust.
  • 1:17pm The payload fairing, which was used to protect the satellite from friction in the Earth’s atmosphere, was successfully separated. The launcher is set to ‘barbecue mode’ – slowly rotating the spacecraft to provide equal exposure to sunlight and avoid overheating.
  • 1:26pm Separation of main stage.
  • 1:26pm Ignition of upper stage: a vital part of the launch, given the difficulties of ignition in space.
  • 1:27pm JUICE lost signal from the Natal tower off the coast of Brazil.
  • 1:27pm No signal between the two towers for 63 seconds.
  • 1:28pm Confirmation of signal from Ascension Island. “Very smooth flight” as it crossed the South Atlantic ocean towards continent of Africa.
  • 1:37pm JUICE reaches altitude of 580km.
  • 1:42pm In Earth’s orbit, JUICE safely separates from the  mothership on the correct trajectory. Applause in ESA as launch is considered a success.
  • 2:04pm Acquisition of signal from JUICE detected by Western Australian satellite dish after tense delay.
  • 2:33pm Successful deployment of solar wings. “We are going to Jupiter. Get ready for it” is heard in the ESA control room.

JUICE will explore Jupiter and three of its icy moons – Ganymede, Callisto and Europa – for signs of life in their deep reservoirs. But this life is unlikely to photosynthesise given Jupiter’s distance from the Sun.

“ESA, with its international partners, is on its way to Jupiter,” says ESA Director General Josef Aschbacher. “JUICE's spectacular launch carries with it the vision and ambition of those who conceived the mission decades ago, the skill and passion of everyone who has built this incredible machine, the drive of our flight operations team, and the curiosity of the global science community. Together, we will keep pushing the boundaries of science and exploration in order to answer humankind’s biggest questions.”

Jupiter as imaged by the James Webb Space Telescope

Jupiter as imaged by James Webb
Jupiter as imaged by the James Webb Space Telescope © NASA, ESA, CSA, Jupiter ERS Team; image processing by Ricardo Hueso (UPV/EHU) and Judy Schmidt.

The satellite will have to combat Jupiter’s large gravitational pull, radiation belt, harsh temperatures, and the incredibly far journey through deep space as part of its mission. It was vital that JUICE was kept incredibly clean ahead of the launch so that on return ESA will be able to determine whether any biological matter present came from Jupiter.

“The treasure trove of data that ESA Juice will provide will enable the science community worldwide to dig in and uncover the mysteries of the jovian system, explore the nature and habitability of oceans on other worlds and answer questions yet unasked by future generations of scientists," says Carole Mundell, ESA’s Director of Science.

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Paving the way to future exploration

Rocket Ariane 5 with the Jupiter Icy Moons Explorer, JUICE ready for launch on the launch pad at Europe’s Spaceport in Kourou, French Guiana
Ariane 5 VA 260 with the Jupiter Icy Moons Explorer, JUICE, ready for launch on the ELA-3 launch pad at Europe’s Spaceport in Kourou, French Guiana on 12 April 2023 © ESA

Before Jupiter, NASA’s Artemis 2 mission will send four humans to orbit moon, including the first woman and first person of colour on a lunar mission, in late 2024. After this, NASA aims to establish Lunar Gateway – a permanent Moon-orbiting space station. The Artemis programme will pave the way towards ambitions to send the first humans to Mars.

Timeline of JUICE mission: 

  • April 2023 Launch of JUICE satellite
  • August 2024 Lunar-Earth flyby
  • August 2025 Venus flyby
  • September 2026 Earth flyby 1
  • January 2029 Earth flyby 2
  • July 2031 Arrival at Jupiter
  • December 2034-September 2035 Ganymede orbit

The team behind JUICE

The team behind the JUICE mission at ESA mission control
At ESA’s mission control, before the launch comes the pre-launch briefing – and the all-important group photo. This is the team that will fly JUICE to Jupiter with four planetary flybys of Earth and Venus, then switching orbit from Jupiter to its largest moon, Ganymede, followed by a tour of the icy, complex Jovian system comprising a whopping 35 lunar flybys © ESA

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Noa LeachNews editor, BBC Science Focus

Noa Leach is the News editor at BBC Science Focus. With an MPhil degree in Criticism & Culture from the University of Cambridge, Noa has studied cultural responses to the climate crisis, wildlife, and toxicity. Before joining BBC Science Focus, Noa was the Editor of The Wildlife Trust BCN’s magazine Local Wildlife. Her writing has been shortlisted for the Future Places Environmental Essay Prize.