JUICE's journey to Jupiter
This animation shows the journey of the JUICE spacecraft to Jupiter. The proposed trajectory of JUICE is traced as a white line beginning inside Earth's orbit (shown in blue). By following the trajectory, it is possible to appreciate the gravity-assist strategy—a sequence of flybys of Earth, Venus, Earth, Mars, and again Earth—that is used during the 88-month cruise phase of the mission.
As JUICE starts its first elliptical solar orbit, its distance to the Sun decreases. This results in an increase in speed—according to Kepler's second law of planetary motion—and the spacecraft overtakes Earth. During this first orbit, JUICE has maximum speed at perihelion, when it is closest to the Sun, but loses speed as it approaches aphelion.
By the time the first solar orbit is complete, Earth has caught up with JUICE and the first gravity-assist manoeuvre can be performed. At this point, the spacecraft is deflected towards Venus (whose orbit is shown in yellow) and it falls in the direction of the Sun, increasing speed. Crucially, each planetary flyby also causes orbital angular momentum to be transferred from the planet to the spacecraft. The acquisition of planetary angular momentum causes JUICE to further increase speed and is the key to the flight strategy. At launch, JUICE will not have sufficient fuel for a direct transit to Jupiter and therefore a series of planetary flybys is essential to allow the spacecraft to incrementally gain enough energy to reach its destination.
After passing Venus, JUICE makes subsequent flybys of Earth, Mars (whose orbit is depicted in red), and Earth again before its rendezvous with Jupiter in October 2029. The animation ends at the Jupiter orbit insertion point, so only the first set of gravity-assist manoeuvres that have been choreographed by ESA flight dynamics experts are shown.
The acronym JUICE stands for JUpiter ICy moons Explorer. The main goals of the mission are to explore the habitable zone around Jupiter, and to study the Jupiter system as an archetype of gas giants. To achieve its scientific objectives JUICE will fly past the three icy moons, Callisto, Europa, and Ganymede, and characterise the Jovian system, the planet, and its magnetosphere, before being inserted into orbit around Ganymede, Jupiter's largest moon.
The scenario foreseen for a June 2022 launch of JUICE on an Ariane 5, from Kourou in French Guiana, is as follows:
The first Earth flyby will be at a distance of 12 700 km in May 2023;
JUICE will arrive at Jupiter in October 2029.