Evrim Yazgin
Cosmos science journalist
The European Space Agency (ESA) JUICE mission is on its way back to Earth. But it won’t be staying long.
JUICE (Jupiter Icy Moons Explorer) is about to do something no other spacecraft has done before. It’s about to attempt a “slingshot” manoeuvre as it plots its course to the largest planet in our solar system: Jupiter.
In taking the scenic route, JUICE is also the first spacecraft to perform a lunar-Earth flyby.
For the first time, a spacecraft will attempt to use the gravity of celestial bodies – in this case, the Moon and our own planet – to change speed and direction, helping it on its journey through space.
But it’s a daring manoeuvre. The slightest mistake or miscalculation could see JUICE flying off course and cut its mission short.
JUICE was launched in April 2023. After its “slingshot” passes the Moon and Earth, it is expected to complete a flyby of the planet Venus in August 2025. This, followed by another two flybys passing Earth, will see the spacecraft focus its attention on reaching Jupiter.
Jupiter is on average 800 million km from Earth. For such a long journey, JUICE would need an impossible amount of fuel – 60 tonnes. Additional propellant would have to be on board to slow the spacecraft for its descent into Jupiter’s orbit.
Instead, the mission team has spent 20 years developing a route which is assisted by the gravity of planetary bodies to get JUICE to its destination in a more fuel-efficient manner.
Operators have already had to adjust JUICE’s path so it arrived at the Moon, and again to make sure it heads to Earth at the right trajectory.
JUICE will be in Earth’s orbit on 19–20 August. It may even be visible in the night sky to some keen viewers on the ground. It is going to fly directly over Southeast Asia and the Pacific Ocean. You can follow its flight path on the ESA’s website here.
The spacecraft will be in continuous contact with ground stations around the world between 17 and 22 August. Any slight alterations to keep it on course will be made during this time.
JUICE’s primary mission is to investigate and gather data on Jupiter’s icy moons Ganymede, Callisto and Europa using an array of remote sensing, geophysical and in situ instruments. The mission may even help in the search for life beyond our planet.
