Moon, Earth, Jupiter: How JUICE’s Triple Threat Flyby is Changing the Game

The European Space Agency’s (ESA) JUICE mission is set to make history with its unprecedented Lunar-Earth Gravity Assist (LEGA) maneuver, also known as a slingshot, scheduled for August 19-20, 2024. This isn’t just another routine flyby; it’s a groundbreaking event in space exploration, marking the first time a spacecraft will use both the Moon and Earth in a single gravity assist. 

Gravity assists, like the LEGA, are ingenious techniques that allow spacecraft to change their speed and direction using the gravitational pull of celestial bodies,without expending much fuel. What makes this maneuver particularly special for the JUICE mission is its dual-object approach. First, JUICE will pass by the Moon, which will slightly reduce its speed. Then, it will loop around Earth, further slowing down and aligning itself on a precise path toward Venus.

This might sound surprising,after all, shouldn’t JUICE be speeding up to reach Jupiter? But in the realm of space navigation, this controlled deceleration is a brilliant strategy. By carefully navigating through the inner Solar System, JUICE can conserve a significant amount of fuel, which is important for the mission’s long journey and for the detailed studies it will conduct of Jupiter’s icy moons, particularly Ganymede.

This proximity will enable JUICE to conduct detailed studies of the moon’s ice-covered surface and its potential subsurface ocean, which may harbor conditions favorable for life. Moreover, the LEGA will also provide a unique opportunity to test and calibrate JUICE’s scientific instruments, ensuring they are fully operational before the spacecraft enters Jupiter’s harsh environment.