The European Space Agency’s Juice mission is on its way to explore Jupiter’s icy moons. It will arrive there in a few years, but to get there it will steal some orbital velocity from Earth, Venus and – for the first time – the Moon. These gravity assist maneuvers are standard for slingshot missions in the solar system, but what JUICE did last night and will do tonight is anything but.
For the first time, a spacecraft is using two objects for a gravity maneuver instead of just one. This is the first Moon-Earth flyby to be conducted over two nights. It’s such a daring maneuver that the launch window for the mission last year was only allowed one second. Last night, Juice successfully flew by the Moon and conducted some tests of the scientific instruments, including those that will study what lies beneath the icy surface of Jupiter’s moons. In the second leg, Juice will fly by Earth tonight.
“This would not have been possible in the laboratory. This will be an excellent test to check the performance of the radar in the context of the full operation of the spacecraft,” said Nicolas Altobelli, planetary scientist at ESA, during a press conference attended by IFLScience 10 days ago.
The Moon was imaged by JUICE on August 19, 2024 at 21:25 UTC, shortly after its closest approach to the Moon.
Image source: ESA/JUICE/JMC, Acknowledgements: Simeon Schmauß & Mark McCaughrean
While the focus is mainly on the scientific aspects, the cameras are also being tested. Several images have already been shared online, some of which have been slightly edited, like the main image above, to show real color differences on the moon.
This image was not taken with a scientific camera. It is from the Juice Monitoring Camera, which is used to check the condition of the booms and antennas.
The spacecraft will fly past Earth in just a few hours, putting it on track to reach Venus in August 2025. It will then return to Earth twice, in September 2026 for more gravitational assistance and then again in January 2029.
All flybys will provide the speed needed to reach Jupiter in 2031. There, Juice will spend three years studying the system as a whole, as well as Europa, Ganymede and Callisto, before orbiting Ganymede alone.
