The European Space Agency’s Jupiter Icy Moons Explorer, JUICE for short, has transmitted back the first views from its highest-altitude-scientific-camera-ever-flown, JANUS. of the Moon and Earth. These first snapshots of the moon and Earth, taken during JUICE’s historic flyby, mark the spacecraft’s first glimpse of these two celestial objects as it continues its trek toward Jupiter and its icy moons.
Launched on April 14, 2023, JUICE has just conducted a perfect flyby of the Earth and Moon, putting it on a Venus-bound trajectory. It is executed to perform additional gravity assists by several Earth flybys—once in 2026 and a further two in 2029—designed to get JUICE to the system of Jovian planets, of which Jupiter is the biggest and its ultimate destination by July 2031.
“The gravity assist flyby was perfect; all went smoothly, and we could not be happier with the results of seeing JUICE return so close to Earth,” said JUICE Spacecraft Operations Manager Ignacio Tanco. The spacecraft had its lunar flyby at 6:15 pm EDT on August 19 and followed it up with its Earth flyby just over a day later. These are important maneuvers that will help shape JUICE’s trajectory with very restrained fuel use, using the gravitational pull of celestial objects.
The imaging system of JUICE, JANUS, has been designed to image Jupiter and its moons at detail levels that have never been achieved so far. During the lunar-Earth flyby, JANUS tested the different camera settings and time intervals for its functionality. Some images have purposely been blurred to test the resolution recovery algorithms, while some are partially saturated to study its unsaturated area effect.
The name JANUS is an abbreviation of “Jovis, Amorum ac Natorum Undique Scrutator,” which in Latin means “Scrutiniser of Jupiter, and all his loves and descendants.” The name was due to the reflection and evocation of the mission’s focus on the four biggest moons of Jupiter, which are named after lovers of Zeus in Greek mythology.
As a primary mission, JUICE flew by, providing an extra dimension of interest to the photographs. These observed that the Moon is not, in reality, absolutely colorless and gray but carries some tints of blue and red. The European Space Agency commented that the color contrasts emanate from volcanic activity on the Moon, which exhibits very diverse basaltic rocks and lava flows.
Andrew Coates, a physics professor, and JANUS camera co-investigator, explained that basalt areas are less reflective than brighter terrains on the Moon. He added that subtle color differences might be brought about by slight differences in composition, modulated by sunlight and camera calibration.
The flyby, mainly designed to put JUICE on the correct trajectory, also provided ESA with an early opportunity to test the spacecraft’s 10 science instruments. Eight of them were switched on when JUICE arrived at Earth, and the collected data will also help prepare for the spacecraft’s future encounter with Jupiter.
“Timing and location of this double flyby permit scrutiny of the performance of JUICE’s instruments,” explained Claire Vallat, an operations scientist on the mission. She underscored how this flyby will help gather data in preparation for the operational mission of the instruments at Jupiter.
As JUICE continues its journey, scientists all over the globe are anticipating more detailed, much higher-resolution images and data to be returned from the space probe’s JANUS camera. Even from these very first images, our view of the lunar surface has been transformed. We can only guess what will come from JUICE’s up-close look at Jupiter and its icy moons.
In the end, the ESA’s JUICE spacecraft will have conducted one of the greatest actions in the exploration of space bypassing the Earth and the Moon flyby. Breathtaking images by the JANUS camera will certainly enlighten new things about the Moon and open new horizons for the upcoming findings in the Jovian system.