(CNN) –– The European Space Agency's Juice mission is about to reach two historic milestones in its long journey to study the possible habitability of Jupiter's icy moons.
The Jupiter Icy Moons Explorer, or Juice, which launched in April 2023, will perform its first successive flyby of the Moon and Earth and its first dual gravity assist maneuver on Monday and Tuesday. This process will serve as a slingshot that will allow Earth's gravity to slow Juice's current trajectory and redirect it to flyby Venus in August 2025.
Juice will then be able to take a shortcut through the solar system and be on track to reach Jupiter and its moons in July 2031.
Juice will first pass Earth's moon on Aug. 19 at 5:16 p.m. ET, and then pass Earth nearly 25 hours later at 5:57 p.m. ET on Aug. 20. The space agency will provide a Animated tracking of spacecraftand some people with binoculars or telescopes in Southeast Asia will be able to see Juice as it flies directly over Earth.
Meanwhile, Juice's two cameras will take pictures during the flyby and send them back to Earth, to be later published in the agency site.
But pioneering maneuvers are also incredibly daring and challenging, and one small mistake could send Juice off course and the mission over.
“It’s like going through a very narrow corridor, very, very fast: stepping on the accelerator to the maximum when the margin on the side of the road is just millimeters,” explained Ignacio Tanco, Juice’s Spacecraft Operations Manager, in a statement.
On average, Jupiter is 800 million kilometres from Earth, so getting there without a massively powerful rocket and thousands of litres of fuel on board requires careful mission planning. And the plan for Juice's journey has been in the works for 20 years.
By using the gravity of planets like Earth and Venus, adjustments can be made to Juice's trajectory to put it on the right course and at the optimal speed to reach Jupiter and enter orbit without zooming past the planet.
Gravity assists can speed up or slow down spacecraft, depending on how they are used, and they allow spacecraft to conserve fuel and equip them with a host of scientific instruments.
The double pass by Earth and the Moon will slow Juice down enough for it to fly by Venus and get a boost of energy next year before making two trips around our planet for more boosts, According to the agency.
Small adjustments to Juice's flight pattern allowed the spacecraft to arrive at the right time and speed to reach both the Moon and Earth in extreme proximity. Juice will first pass within 700 kilometers (430 miles) of the Moon's surface and then fly within 6,807 kilometers (4,300 miles) of Earth's surface.
The Moon's gravity will slightly deflect Juice's trajectory so that it receives a much stronger gravitational assist from Earth. But every detail of the double flyby must be perfect.
“For a typical gravity assist, spacecraft operations must be extremely precise,” said Angela Dietz, Juice spacecraft operations engineer, in a statement. “For a double flyby, they must be exact.”
Operators using ground stations around the world will closely monitor Juice data before, during and after the flyby to make necessary adjustments at any time.
The flight control team trained and rehearsed for the flyby in case any anomalies occur, they can get Juice back on track quickly.
“A flyby of the Moon to Earth has never been attempted before,” Dietz said. “There are risks, but all of the systems onboard Juice have been rigorously tested and we are well prepared.”
Although Juice was designed to explore the cold, dark regions of the solar system near Jupiter, it will be closer to the sun during the flyby and will need to tilt its solar panels to avoid overheating. The spacecraft will also point its high-gain antenna toward the sun to act as a heat shield, while its low-gain antenna will remain pointed toward Earth to relay communications during the flyby.
Telescopes and observatories have been tracking Juice's approach all summer.
On July 6, an object triggered NASA and ESA's automated alert systems that monitor for potentially hazardous asteroids. The object was estimated to be 50 meters in diameter and was about to pass very close to Earth and the Moon.
But it was actually Juice, and since it has large reflective solar panels, the spacecraft It looked much bigger and brighteras an asteroid. Agencies confirmed that Juice poses no risk to Earth or the Moon during its passage.
Juice will also activate its 10 science instruments during the double flyby to calibrate them before reaching Jupiter. In addition to testing the instruments, the mission team could also make some discoveries about Earth and the Moon while the instruments are in operation.
The RIME team, which is in charge of the Radar for Icy Moon Exploration instrument, is eager to gather data on the electronic noise inside the spacecraft that appears to be disturbing the instrument. This could be one of the few opportunities to measure any impact on the instrument before it reaches Jupiter.
During the flyby, RIME will take eight minutes to make observations while other instruments are shut down or go into silent mode, and that data could help the mission team troubleshoot the noise problem.
