ESA JUICE probe targets dark Jovian moon Kallichore in 2031

The European Space Agency’s Jupiter Icy Moons Explorer (JUICE) spacecraft is set to conduct a close flyby of Jupiter’s small, irregular moon Kallichore in October 2031, according to recent research published in Nature. The study, conducted by an international team of scientists, aimed to gather critical data about Kallichore to aid in planning the trajectory for the upcoming encounter. The findings refine the understanding of the moon’s size, brightness, and orbital path, reducing the uncertainty around its position during the flyby by approximately 80%. Kallichore, one of Jupiter’s many lesser-known satellites, has an average diameter of 3.8 kilometers (2.4 miles) and follows an irregular, highly elliptical orbit around the gas giant. Unlike the well-studied Galilean moons such as Europa, which has a diameter of roughly 3,122 kilometers (1,940 miles), Kallichore represents a class of celestial bodies that offer unique insights into the early solar system. These irregular moons, which constitute nearly 87% of all known moons in the solar system, have remained largely unaltered over billions of years, preserving records of the primordial conditions of the cosmos. The research team used data collected from NASA’s Hubble Space Telescope and the Gran Telescopio de Canarias, a large optical-infrared telescope located on the Canary Island of La Palma. By combining observations from both space- and ground-based instruments, the scientists determined that Kallichore’s geometric albedo, a measure of how much light it reflects, is only 0.037, making it exceptionally dark. This low reflectivity suggests the moon is composed of materials that absorb rather than reflect sunlight, possibly indicating a surface rich in carbon-based compounds or organic material. Precise knowledge of Kallichore’s orbit is crucial for ensuring the success of the JUICE mission. Prior to this study, the estimated position of Kallichore at the time of JUICE’s arrival in the Jupiter system carried an error margin of about 272 kilometers (169 miles). With the newly refined data, this margin has been reduced to approximately 30 kilometers (19 miles), significantly increasing the likelihood of a successful flyby. The improved accuracy allows mission planners to design a trajectory that brings JUICE within a few hundred kilometers of Kallichore, enabling detailed imaging and spectroscopic analysis. Irregular moons like Kallichore are considered valuable targets for planetary scientists seeking to understand the origins of the solar system. While the search for extraterrestrial life often focuses on the Galilean moons, particularly Europa, which is believed to harbor a vast subsurface ocean, irregular moons offer a different kind of opportunity. Their relatively untouched surfaces may contain remnants of the earliest materials that formed planets and moons, providing clues about the processes that shaped the solar system billions of years ago. JUICE, launched in April 2023, is scheduled to reach the Jupiter system in July 2031. Its main objective is to investigate the icy Galilean moons, Io, Europa, Ganymede, and Callisto, to assess their potential to support life. However, the spacecraft’s mission extends beyond these major moons. It is also designed to perform a series of flybys of smaller, less-explored satellites, including Kallichore. If the flyby occurs as planned, JUICE will become the first spacecraft to conduct a close-range observation of this particular moon, marking a significant step in the exploration of Jupiter’s diverse satellite system. The study highlights the importance of preparing for such encounters through extensive observational campaigns. Scientists emphasize that while the Galilean moons remain central to astrobiological investigations, the irregular moons offer complementary perspectives on the broader history of the solar system. As JUICE approaches its destination, the refined orbital parameters of Kallichore will play a vital role in determining the feasibility of capturing high-resolution images and collecting spectral data during the brief window of the flyby.