Juice completes Earth fly-by, heads for Venus fly-by
Earth as seen by Juice during fly-by.
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The European probe Juice yesterday successfully completed a close fly-by of the Earth and was thus successfully slingshoted on its way to its next fly-by, of Venus, on its way to Jupiter.
This fly-by was actually a double event. First Juice zipped past the Moon the day before, coming within 435 miles. Then, only one day later it passed the Earth at a distance of 4,230 miles, thus completing the first dual fly-by of the both the Earth and the Moon.
The flyby of the Moon increased Juice’s speed by 0.9 km/s relative to the Sun, guiding Juice towards Earth. The flyby of Earth reduced Juice’s speed by 4.8 km/s relative to the Sun, guiding Juice onto a new trajectory towards Venus. Overall, the lunar-Earth flyby deflected Juice by an angle of 100° compared to its pre-flyby path.
The inherently risky flyby required ultra-precise, real-time navigation, but is saving the mission around 100–150 kg of fuel. In the month before the flyby, spacecraft operators gave Juice slight nudges to put it on exactly the right approach trajectory. Then they tracked Juice 24/7 between 17–22 August.
The Venus fly-by will occur in August 2025, followed by additional Earth flys in September 2026 and January 2029. The spacecraft will finally arrive in Jupiter orbit in July 2031, where it is designed to study the large icy moons (Europa, Gandymede, and Calisto) of that gas giant.
