Europe’s Jupiter spacecraft to take daring flight between Earth and Moon

The Jupiter Icy Moons Explorer (JUICE) mission can be seen in this NASA artist’s impression handout. | Photo credit: NASA

European scientists were scheduled to attempt the first orbital gymnastics late on August 19, using Earth’s gravity to accelerate and guide the JUICE probe toward Jupiter for the first time in a double slingshot maneuver.

Exactly one year after launch, the European Space Agency’s Jupiter Icy Moons Explorer (JUICE) is returning to Earth on August 19-20 and will take a shortcut to reach Venus and onwards to Jupiter, using the braking effect of its gravity.

In a new dual function, the Airbus-built JUICE probe will first use the Moon’s gravity to orbit the exact right path toward Earth.

This is risky because a slight miscalculation in this step would be compounded by the second part of the routine, which involves slowing down the speed using Earth’s gravity. Scientists warn that this could derail the eight-year journey to reach Jupiter and its moons.

“Inherently this is a bit tricky, because you have to correct any errors, and for that you need propellant,” JUICE mission manager Nicolas Altobelli said in an interview.

Scientists have used the “gravity assist” method for decades to travel across the solar system while saving propellant.

This involves passing near a planet or moon and using its gravitational force to speed up, slow down or change course.

But this week’s moon-Earth flight marks the first time two such attempts have been made one after the other.

If successful, this will propel JUICE to reach Jupiter and its three large ocean moons – Callisto, Europa and Ganymede – in 2031, with the aid of three more single gravity assists: Venus in 2025, and then Earth again in 2026 and 2029.

ESA scientists considered several options for getting JUICE to Jupiter without the unrealistically large rocket that would be needed to get it there, without any gravity assists.

Altobelli said that by using the moon’s gravity to change course, they were able to catch up with Earth in front of its orbit around the sun, slowing the probe down, while speeding it up as it passed behind the planet.

This allowed ESA planners to aim at Venus and take advantage of its exceptionally powerful slingshot effect.

“This is a very good configuration of the moon’s position around the Earth … so we are being opportunistic,” Altobelli told Reuters.

Following NASA’s Galileo mission to Jupiter in the 1990s, the ESA-led JUICE mission will orbit the Solar System’s largest planet, fly past its three large icy moons and eventually orbit Ganymede to study the possibility of life there.

“This means studying the conditions and understanding whether those moons could be potential habitats, and whether they could have favorable conditions for life as we know it,” Altobelli said.