Last use of the main engine until 2031

For a mission on an eight-year journey, burning 10% of your fuel reserve in just 43 minutes may seem crazy. But investing all that fuel now will pay off for years to come.

“If all goes well with both parts of this manoeuvre, we likely won’t need to use the main engine again until we enter orbit around Jupiter in 2031,” says Ignacio Tanco, Juice Spacecraft Operations Manager. “For small trajectory corrections between now and then, we will use Juice’s smaller thrusters.”

But that doesn’t mean nothing interesting will happen between now and Juice’s arrival at Jupiter. Quite the opposite, the journey is interesting because it allows Juice to get all the way to Jupiter without firing of its main engine again, reducing the amount of fuel the spacecraft needs and allowing it to be packed full of scientific instruments.

After the Earth-Moon double flyby of 2024 (knows as a Lunar-Earth Gravity Assist; LEGA), Juice will first make one flyby of Venus in 2025 and two further flybys of Earth in 2026 and 2029 (both without the additional boost from the Moon).

“Today’s manoeuvre will ensure Juice arrives at the Earth-Moon system at the right time next year for the double flyby,” adds Ignacio.

“And, thanks to the clever trajectory designed by our Mission Analysis team, that flyby will line it up almost perfectly for all of the others, without us having to fire the main engine again.”

With each flyby, the spacecraft will gain more energy than could be achieved by burning a reasonable amount of fuel – energy that will help it climb towards Jupiter against the pull of the Sun’s gravity.