ESA's Juice Spacecraft Slingshots Past Earth on Long Road to Jupiter

The European Space Agency's Jupiter Icy Moons Explorer swung past Earth on Monday, using the planet's gravity to bend its trajectory and pick up speed on an eight-year journey to the outer solar system. The spacecraft, known as Juice, made its closest approach at 11:45 UTC over the Indian Ocean, passing within 8,640 kilometers of the surface.

The maneuver, ESA's third planned gravity assist for the mission, altered Juice's course by about 20 degrees and added roughly 3.5 kilometers per second to its velocity, according to the agency. "Until now, only one manoeuvre at minus four weeks was needed. It was of relatively small size, but extremely effective," said Angela Dietz, the mission's spacecraft operations manager, in comments released by ESA ahead of the flyby.

Because the spacecraft's path took it through Earth's shadow for several hours overnight, flight controllers had to manage the encounter on battery power alone, without sunlight reaching Juice's solar arrays. Engineers used the extended eclipse and the close pass to calibrate onboard instruments, training navigation and monitoring cameras on Earth and the Moon and taking magnetic field readings as the craft later moved through Earth's magnetotail, per footage and mission notes released by ESA.

An Eight-Year Cruise to Ganymede

Juice launched in April 2023 and has already used a combined Earth-Moon flyby in August 2024 and a Venus flyby in August 2025 to shape its long, looping path toward Jupiter. Monday's pass was the mission's third gravity assist overall. According to the mission's published timeline, summarized on the spacecraft's mission page, Juice is expected to arrive at Jupiter in July 2031 and settle into orbit around the moon Ganymede in December 2034, becoming the first spacecraft to orbit a moon other than Earth's own.

Once there, Juice will spend years studying Ganymede, Europa and Callisto, three of Jupiter's largest moons, each believed to harbor a liquid-water ocean beneath its icy crust. For Juice, Monday's Earth flyby was a comparatively low-key but essential step: mission planners said it accomplished in a single pass what would otherwise have required a far larger and more fuel-intensive engine burn, according to independent tracking of the mission by Universe Today.

No anomalies were reported during the encounter, and mission managers said Juice remained on its planned trajectory as it heads toward its next milestone, a third and final Earth flyby scheduled for January 2029, before its long final approach to the Jupiter system.