The JUpiter ICy Moons Explorer (JUICE) mission is the first major mission under ESA's "Cosmic Vision 2015 – 2025." JUICE will observe the giant gas planet Jupiter and three of its largest moons—Ganymede, Callisto, and Europa. On board is the Particle Environment Package (PEP) instrument suite, which was designed at the University of Bern and assembled from international instruments. Part of PEP is the Bernese Neutral and Ion Mass Spectrometer (NIM), which will take measurements in the moons' atmospheres. The Ganymede Laser Altimeter (GALA) will perform topographic mapping and contribute to a large scale geodesy experiment.
Following previous flybys in 2024 and 2025, JUICE is now returning to Earth for a flyby maneuver on 28 September 2026, where flight controllers will be guiding the spacecraft close to our home planet to alter its speed and direction en route to Jupiter.
Getting a spacecraft to the outer Solar System is no easy feat. JUICE’s journey began almost 3.5 years ago, with its April 2023 launch from Europe’s Spaceport in French Guiana. Since then, flight controllers on Earth have successfully guided it through the first ever lunar-Earth flyby (a ‘braking’ maneuver to take JUICE on a shortcut to Jupiter via Venus) and then a Venus flyby (that bent its orbit and gave it a little extra speed). The flyby on 28 September will bring JUICE within 8640 km of our planet and deflect the trajectory of the spacecraft by about 20 degrees and increase its velocity by about 3.5 km/s.
The closest approach will be over the Indian Ocean at 13:45 CEST (11:45 UTC). Between 15 and 30 minutes before closest approach, JUICE will pass over Australia, travelling from the northeast of the country to the northwest. Amateur astronomers using the right telescope or binocular equipment may be able to track it. Trajectory data can be found on the ESA Cosmos website here.
This interaction will set it up for a final Earth flyby in January 2029, putting JUICE onto the best path to intercept Jupiter in July 2031. More information about the flyby is available on the ESA website here.
