Japan’s Hayabusa2 Faces New Challenges with Tiny Asteroid KY26
Japan’s Hayabusa2 mission is set to encounter the smallest asteroid ever visited by a space mission. New observations indicate that the asteroid, designated KY26, is significantly smaller and spinning faster than previously estimated. The mission aims to rendezvous with and land on this asteroid in 2031.
Astronomers originally estimated KY26 to be about 30 meters (98 feet) in diameter and rotating once every ten minutes. However, according to Toni Santana-Ros, an astronomer at the University of Alicante and affiliated with the University of Barcelona, recent observations using the European Southern Observatory’s Very Large Telescope (VLT) in Chile revealed that the asteroid is actually just 11 meters (36 feet) wide. This size is so compact that it could fit inside the dome of one of the VLT’s eight-meter telescopes. Additionally, KY26 completes a rotation every five minutes, making it a fast-moving target.
The revised measurements present both exciting opportunities and challenges for the Hayabusa2 mission. Olivier Hainaut, an astronomer at the European Southern Observatory, noted, “The smaller size and faster rotation now measured will make Hayabusa2’s visit even more interesting, but also even more challenging.”
Previously, Hayabusa2 successfully returned samples from the much larger asteroid Ryugu, which measures approximately 900 meters (2,953 feet) in diameter, in 2020. The current mission to KY26 is part of an extended project aimed at exploring the characteristics and composition of smaller asteroids, which are believed to pose a higher risk of impacting Earth.
“We have never seen a 10-meter-size (33-foot) asteroid in situ, so we don’t really know what to expect and how it will look,” Santana-Ros explained. The observations suggest that KY26 consists of solid rock chunks rather than forming a loose, dusty rubble pile, although the possibility of a rubble structure has not been entirely dismissed.
These findings, reported on September 18, 2023, in the journal Nature Communications, highlight a significant advancement in understanding small asteroids. Hainaut emphasized the importance of characterizing these objects from Earth, stating, “We can learn much about them without even leaving terra firma.” This capability is crucial for planetary defense, especially considering past events like the 2013 Chelyabinsk meteor explosion, which involved an asteroid slightly larger than KY26.
The implications of this research extend beyond planetary defense. Santana-Ros mentioned that the methods developed for studying KY26 could influence future plans for near-Earth asteroid exploration and even asteroid mining. As the Hayabusa2 team prepares for this groundbreaking mission, the scientific community eagerly anticipates the insights this tiny asteroid may reveal.
