The European Space Agency’s (ESA) Juice spacecraft, launched in April 2023, is preparing for a historic manoeuvre as it makes its way to Jupiter. The spacecraft, currently 10 million kilometers from Earth, will execute a unique double gravity assist, leveraging the Moon and Earth’s gravitational fields to conserve fuel on its eight-year mission to study Jupiter’s icy moons: Ganymede, Callisto, and Europa.
This groundbreaking manoeuvre, planned from the ESA’s space operations center in Darmstadt, Germany, will see Juice fly 750 kilometers above the Moon on August 19 and then pass close to Earth the following day. By using the Moon’s gravity, Juice will increase its speed to 3.3 kilometers per second, compared to 3 kilometers per second without the Moon’s assist.
Juice’s approach involves utilizing gravitational assists, a method where spacecraft gain speed and adjust their trajectory by passing close to planets. This mission will be the first to use a double gravity assist from both the Moon and Earth. While previous missions have employed gravity boosts from individual planets, this combined approach is a “world first” for space exploration.
During its flyby, Juice will capture images and test its instruments. Some amateur astronomers in Southeast Asia may catch a glimpse of the probe through telescopes or powerful binoculars.
The manoeuvre has been meticulously planned, with the ground team monitoring the spacecraft closely to ensure precision. Any miscalculation during the Moon slingshot could affect Juice’s trajectory, risking it entering Earth’s atmosphere.
Following this flyby, Juice will continue its journey, with planned boosts from Venus in 2025 and additional Earth flybys in 2026 and 2029 before arriving at Jupiter in July 2031. The spacecraft will perform 35 gravitational assists as it explores Jupiter’s moons, with its trajectory expected to resemble “a real plate of spaghetti,” according to ESA’s Arnaud Boutonnet.
