ESA’s JUICE probe to perform 1st-ever Moon-Earth flyby on august 19-20

New Delhi, Aug 5
The European Space Agency’s (ESA) Jupiter Icy Moons Explorer (Juice) will flyby Earth on 19-20 August, with flight controllers guiding the spacecraft past the Moon and then Earth, the agency reported on Monday. The Moon flyby is expected to take place on 19 August at 23:16 CEST( 2:46 am in Indian Standard Time).

The Earth flyby should take place at 23:57 CEST(3:27 am in Indian Standard Time) on 20 August (nearly 25 hours later). This 'braking' manoeuvre will take JUICE on a shortcut to Jupiter via Venus. “This manoeuvre will mark a double world first: the first lunar-Earth flyby and first double 'gravity assist' by a spacecraft”, ESA said in a post on X.com

This will change JUICE’s speed and direction to alter its course through space. The slightest mistake could take Juice off course and spell the end of the mission. Following JUICE’s launch in April 2023, this lunar-Earth flyby is the first step in the spacecraft’s journey through the Solar System to Jupiter.

On 19-20th August Earth will bend JUICE’s trajectory, ‘breaking’ it and redirecting it for a flyby of Venus in August 2025. From that moment on, the energy boosts will begin, with JUICE being whizzed up by Venus and then twice by Earth.

Jupiter is on average 800 million km away from Earth. Without an enormous rocket, sending JUICE straight to Jupiter would require an impossible 60,000 kg of onboard propellant. JUICE would also need additional propellant to slow down enough to go into orbit around Jupiter, so to circumnavigate this problem it is using the gravity of other planets to adjust its trajectory and ensure it arrives at Jupiter with the right speed and direction.

This complex route has been carefully planned by JUICE’s mission analysis team over the last 20 years. Using the lunar-Earth flyby to slow Juice down is more efficient than using the flyby to speed it up. This first 'braking' manoeuvre is a way of taking a shortcut through the inner Solar System. Mission operators have adjusted Juice’s path to ensure it arrives first at the Moon, then at Earth, at precisely the right time, with the right speed, and in the right direction.

“It’s like passing through a very narrow corridor, very, very quickly: pushing the accelerator to the maximum when the margin at the side of the road is just millimetres,” said JUICE’s Spacecraft Operations Manager, Ignacio Tanco. From 17-22 August, Juice will be in continuous contact with ground stations around the world.