The European Space Agency’s Juice spacecraft skimmed 8,640 km above the Indian Ocean on September 28, 2026, using Earth’s gravity to increase its velocity by 3.5 km/s and deflect its trajectory by 20 degrees.
Propellant Conservation During the Indian Ocean Flyby
Flight controllers managed the close pass to ensure the spacecraft preserved fuel for its future orbital missions. Juice reached its closest point to Earth at 13:45 CEST (11:45 UTC) on September 28, 2026, passing 8,640 km above the Indian Ocean while operating onboard monitoring cameras, according to the European Space Agency. Angela Dietz, Juice’s Spacecraft Operations Manager, stated that careful planning meant the team used only a small amount of the propellant reserved for the flyby.
This fuel preservation leaves more resources available for observations of Jupiter’s icy moons once the spacecraft arrives.
Juice Flyby Helps Calibrate Ten Scientific Instruments
The flyby served as an active test environment for Juice’s ten scientific instruments. Claire Vallat, Juice project scientist, explained that the journey provides limited opportunities to calibrate instruments under well-understood conditions before reaching the Jovian system.
Trajectory Adjustments Compared with Prior Missions
The September 2026 encounter marks Juice’s third planetary calibration opportunity, following a 2024 lunar-Earth gravity assist, a Venus flyby in August 2025, and observations of Comet 3I/ATLAS. According to BBC Sky at Night Magazine, the 2024 maneuver was the first twin Earth-Moon gravity assist ever conducted.
While the 2026 flyby successfully redirected Juice’s path across the inner solar system, the spacecraft faces a much more demanding operational phase upon reaching the gas giant. Juice is scheduled to perform 35 flybys of Ganymede, Callisto, and Europa after entering orbit in 2031.
Frequently Asked Questions About the Juice Spacecraft
When is Juice scheduled to arrive at Jupiter?
Juice is scheduled to reach Jupiter in 2031 to begin its mission studying the gas giant and its ocean-bearing moons Ganymede, Callisto, and Europa, as reported by BBC Sky at Night Magazine.
How many total Earth flybys does the mission include?
The spacecraft conducted a twin Earth-Moon flyby in August 2024, its second Earth flyby on September 28, 2026, and has a third and final Earth flyby scheduled for January 2029.
What was the exact speed increase provided by the September 2026 flyby?
The gravity assist increased Juice’s velocity by 3.5 km/s, which equates to a speed boost of 12,000 km/h, while redirecting its trajectory by 20 degrees.
Upcoming Trajectory Adjustments in January 2029
Juice will return for its third and final flyby of Earth in January 2029. That final encounter will place the European Space Agency spacecraft on the precise trajectory needed to reach Jupiter in 2031, concluding the series of inner solar system gravity assists required to shape its eight-year cruise.
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