The first European mission to Jupiter has officially begun. The European Space Agency’s (ESA) probe JUICE was launched atop an Ariane 5 rocket from the European spaceport in Kourou, French Guiana, on Friday, April 14. Separation of the spacecraft occurred approximately 28 minutes after liftoff.
The launch marked the start of an ambitious mission to study Jupiter and three of its largest and most intriguing moons: Ganymede, Callisto, and Europa, all of which are thought to host large oceans of liquid water beneath their icy shells. “The main goal is to understand whether there are habitable environments among these icy moons and around a giant planet like Jupiter” said planetary scientist and JUICE team member Olivier Witasse.
Gravity slingshots
JUICE (Jupiter Icy Moons Explorer) will take an energy-efficient path towards the king of planets, making close flybys with four planets. The first of these encounters will take place in August 2024 and involve both the Earth and the Moon. JUICE will be the first probe ever to benefit from the Earth–Moon gravity slingshot.
“This will be the most accurate gravity assist manoeuvre ever achieved” said Alessandro Atzei, a JUICE team member and ESA scientist. The JUICE probe will receive its second gravity assist from Venus in August 2025, then pass by Earth for additional encounters in September 2026 and January 2029, if all goes according to plan.
After this last encounter with Earth, the solar-powered spacecraft will head more directly towards Jupiter, finally reaching the gas giant in July 2031. JUICE will make one last flyby, this time around Jupiter’s moon Ganymede, to enter Jupiter’s orbit.
Scientific mission
JUICE’s scientific mission will begin even before it reaches Jupiter. Six months before orbital insertion, the spacecraft will begin observing the Jovian system using its suite of 10 scientific instruments. These include the most powerful geophysical remote sensing instrument ever flown to the outer Solar System. The instruments include an optical camera system, spectrometers, a radar altimeter, a laser altimeter, a magnetometer, and particle analysers.
Data collection will intensify when JUICE reaches Jupiter. The spacecraft will study the gas giant in depth and also observe Ganymede, Callisto, and Europa. Observations of the three moons will be made up close, during 35 close flybys between 2031 and 2034.
Twenty-one of these close flybys will involve Callisto, which is the most heavily cratered satellite in the solar system. JUICE will first fly by Europa twice, searching for possible pockets of liquid water beneath its icy shell. The JUICE probe will then fly by Ganymede a dozen times, and in December 2034, it will enter orbit around this largest moon of the planet Mercury. It will be the first time a spacecraft has orbited a satellite other than the Moon until its fuel is depleted.
Expectations of the scientific community
“JUICE will characterise the icy moons of Jupiter, Ganymede, Europa, and Callisto, as possible habitats. It will explore the complex environment of Jupiter and study the Jupiter system as an archetype for gas giants throughout the universe” said ESA officials.
“We have a lot to do to meet the objectives of the scientific community. One highlighted objective is the need to learn more about the liquid water beneath the surface of the icy moons” added Witasse in the April 6 briefing. “It’s quite fascinating to think that, beneath these icy surfaces, there is a lot of liquid water. And this will truly be the most interesting aspect of the mission.”