Next month, amateur astronomers might be able to spot the ESA’s Jupiter Icy Moons Explorer-or JUICE-spacecraft as it performs an audacious double flyby of the Moon and Earth. Scheduled for August 19 and 20, the event marks a significant milestone in the agency’s spacecraft on its journey to unlock the secrets of Jupiter and its largest moons.
When it launched in April 2023, the $1.1 billion JUICE mission undertook an audacious endeavor: to investigate Ganymede, Callisto, and Europa-three moons presumed to host liquid-water oceans beneath their frozen surfaces. The flyby that is about to happen will slingshot JUICE toward its intended destination, giving it a gravitational boost.
On August 20, at 5:57 pm Eastern time, JUICE will have the closest approach to Earth at an altitude of just 4,200 miles above the surface of the planet. It will pass over Southeast Asia and the Pacific Ocean, which means it will be a very short opportunity for observers in these regions to spot the spacecraft. “Powerful binoculars or a telescope will give you the best chance of seeing the spacecraft,” the officials shared.
The double flyby is a trickier maneuver that needs highly exceptional precision. The accuracy should be pinpoint, says Angela Dietz, a JUICE Spacecraft Operations Engineer; even the least deviation will send the spacecraft off track. The first will be the lunar flyby; JUICE will fly just 700 kilometers above the Moon’s surface on August 19th at 23:16 CEST. All but exactly 24 hours later, it shall pass 6,807 kilometers above Earth’s surface.
It’s like passing through a very narrow corridor, very, very quickly: pushing the accelerator to maximum when the margin at the side of the road is just millimeters, explained Ignacio Tanco, the operations manager of the mission. Beginning on August 17, ground stations globally will monitor JUICE in continuous succession until the mission ensures that the spaceship stays on course.
Meanwhile, the mission team will seize the opportunity to test JUICE’s 10 science instruments, among them the partly deployed RIME antenna. For eight minutes, the engineers will have RIME all to themselves to check out its performance and possibly work out a new algorithm for continuing electronic noise.
But the double flyby comes with risks: the spacecraft will sweep inside the altitude of satellites in geostationary and medium-Earth orbits, and it will have to scan for space debris in order to make sure the passage is safe. The ESA’s Space Debris Office will be on high alert in order to ward off the possibility for a collision.
The two cameras on board JUICE will send back images of the Moon and Earth during the course of the flyby, which will be shared on social media once they are received on Earth. This is a huge milestone in the mission of JUICE because the spacecraft is one step further toward unleashing the secrets of Jupiter and its icy moons.