KOUROU, French Guiana — The European Space Agency’s Jupiter Icy Moons Explorer, known as Juice, is preparing to perform its third and final gravity assist at Earth, a maneuver designed to adjust the spacecraft’s trajectory and speed before it heads toward Venus and ultimately Jupiter. The spacecraft was launched on April 14, 2023, from Europe’s Spaceport in Kourou, French Guiana, aboard an Ariane 5 rocket. It is on an eight-year journey to study Jupiter’s three large icy moons: Ganymede, Callisto, and Europa.
Juice previously conducted a lunar-Earth double flyby on August 19-20, 2024, and a second Earth flyby on August 20, 2024. This third Earth gravity assist will use the planet’s gravity to change the spacecraft’s direction and speed, setting it on a course for a flyby of Venus in August 2025.
Trajectory and Timeline
After the Venus encounter, Juice will perform two more Earth flybys in September 2026 and January 2029 before finally arriving at Jupiter in July 2031. The mission’s primary goal is to characterize the icy moons’ subsurface oceans, which are considered prime candidates for hosting conditions suitable for life. Juice carries a suite of remote sensing, geophysical, and in-situ instruments, including cameras, spectrometers, a radar sounder, a laser altimeter, and magnetometers.
The spacecraft is the first mission to orbit a moon other than Earth’s Moon, as it will enter orbit around Ganymede in December 2034. The mission is led by ESA with contributions from NASA, JAXA, and other international partners.
The gravity assist maneuvers are critical for saving fuel and enabling the spacecraft to reach Jupiter with its limited propellant. During the Earth flyby, mission controllers will also calibrate some of Juice’s instruments.
What to Watch
The exact date of this third Earth gravity assist has not been specified, but it is part of the mission’s ongoing trajectory adjustments. The flyby is expected to occur in the coming days or weeks, and the spacecraft will pass at a safe distance from Earth. The public can follow the mission via ESA’s website and social media channels.
Juice is one of the most ambitious planetary science missions ever undertaken by Europe, and its success will depend on these carefully orchestrated planetary encounters.
