JUICE exploring the Jovian system. Credits: ESA

JUICE mission is on its way to Jupiter: let’s discover it better

On April 14, 2023, ESA launched the JUICE mission on board an Ariane 5 rocket. JUICE will reach Jupiter in 2031 to study icy moons Europa, Callisto and Ganymede

JUICE mission is finally launched towards Jupiter!

After a launch reschedule, Jupiter Icy Moons Explorer (JUICE) is finally on its way to Jupiter. The Ariane 5 launcher, hosting JUICE, left Earth on April 14, 2023, at 12.14 UTC  from Europe’s Spaceport in French Guiana. JUICE launch will be the last flight for Ariane 5, ending the almost 30-years career of the launcher that will be replaced by Ariane 6.

After approximately 40 minutes from the launch, JUICE separated from the Ariane 5 upper stage and the first positive signals were acquired shortly after.

Ariane 5 leaving the launchpad with JUICE on board. Credits: ESA
Ariane 5 leaving the launchpad with JUICE on board. Credits: ESA/S.Corvaja

A bit of history

JUICE is the first Large (L-class) mission (with a budget of more than €900 million) in ESA’s Cosmic Vision 2015-2025 program. Such a program was firstly defined in 2004 with the aim of designing space missions to answer questions about planetary formations, Solar System fundamental mechanisms and origins. In 2007, ESA opened the call for missions proposals that attracted almost 60 designs, among which the early design of JUICE, originally called Europa Jupiter System Mission. Just for reference, the latest ESA call was in January 2022 for the next Medium (M-class) (€550 million) and Fast (F-class) (<€175 million) missions that aim to fly in the next twenty years.

In March 2012, after a re-design of the mission to meet budget constraints, ESA announced the selection of JUICE and in 2014 started the development phase.


What happens after launch?

JUICE is launched in a quasi-circular orbit around the Sun. It follows a quasi-resonant transfer with the Earth whose main function is to allow a plane change at the Earth flyby (planned for August 2024) to swing the orbit plane to the ecliptic. JUICE will then pass-by Venus in August 2025, allowing it to obtain an orbit that will intersect the Earth again with increased energy. In fact, JUICE will encounter the Earth in September 2026 and in January 2029 with a rather high relative velocity to increase the orbit apoapsis gradually up until the Jupiter encounter in July 2031.

Infographic of JUICE mission trajectory towards Jupiter
Infographic of JUICE interplanetary trajectory to Jupiter. Credits: ESA

JUICE through the Jovian System

The spacecraft then enters Jupiter’s sphere of influence and will exploit a combination of thrust maneuvers and flybys with Ganymede to reduce its speed compared to Jupiter, allowing the capture in its sphere of influence. Ganymede is particularly useful for this purpose as it is the largest moon in the Solar System. The orbit reduction phase is expected to end in 2032. The moon tour can then begin with 35 flybys at Jovian moons Europa, Callisto and Ganymede.

Europa flybys (in 2032) provide unique opportunities to study the moon’s active zones, looking for liquid water under the surface ice via radar measurements. A sequence of resonant flybys with Callisto is then used to modify JUICE orbital inclination to explore Jupiter’s higher latitudes ( all the moons used for flybys are in equatorial orbits around Jupiter), to analyse Jupiter’s atmosphere and magnetic field from a privileged view.

Artist impression of JUICE flyby of Callisto (credit: ESA)
Artist impression of JUICE flyby of Callisto. Credits: ESA

Ganymede and Callisto flybys (2033-2034) are then used to reduce the orbital inclination back to nearly zero degrees with respect to Jupiter’s equator and to reduce JUICE velocity compared to Ganymede, that is the final target of the mission. JUICE will then enter Ganymede’s sphere of influence and will remain in orbit around Ganymede until 2035. This is also an unprecedented result, as JUICE will be the first spacecraft to orbit a moon other than our own.


Why Jupiter Icy Moons?

The main objective of the mission is to study Ganymede, as it is a natural laboratory for studying evolution and potential habitability of icy worlds. Ganymede is also the only moon in the Solar System to have a magnetic field. JUICE will thus study not only Ganymede’s subsurface and hidden oceans, but also its mass and internal core dynamics and the relationship with Jupiter’s magnetic field. At the end of 2035, JUICE will use the remaining propellant to deorbit and crash on Ganymede.

JUICE will not be alone around Jupiter. Juno spacecraft (NASA) arrived in a polar orbit around Jupiter in 2016 and it is still operative after several mission extensions, mapping Jupiter’s gravitational and magnetic fields. Europa Clipper (NASA) will launch in 2024 and will arrive at Jupiter in 2030 to search for potential life on Europa and to select a landing site for future landers.

To conclude, good luck to JUICE, and see you on Jupiter!


Andrea Bellome

Andrea Bellome

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