The Japanese space mission Hayabusa2 faces challenges after researchers discovered facts about its target asteroid, KY26. The asteroid, which is planned to be visited in 2031, turns out to be much smaller than previously thought and rotates twice as fast as expected.
Initially, astronomers estimated that KY26 had a size of around 30 meters with a rotation time of around 10 minutes. However, the latest observation results from a number of world telescopes, incl Very Large Telescope (VLT) property European Southern Observatory (ESO) in Chile, shows a different reality.
Asteroid KY26 turns out to only be 11 meters in diameter or about a third of its original size. In fact, it is so small that this celestial body is said to be able to fit inside the dome of one of VLT’s giant eight-meter diameter telescopes. Not only that, the KY26 also spins very fast, it only takes five minutes to complete a full rotation.
“This smaller size and faster rotation makes Hayabusa2’s visit even more interesting, but also much more challenging,” said astronomer from ESO, Olivier Hainaut, quoted from the Space page.
Hayabusa2 previously had great success after landing on the asteroid Ryugu in 2020 and bringing samples back to Earth. Now, on a follow-up mission, the spacecraft belongs to Japan Aerospace Exploration Agency (JAXA) is heading towards KY26 with a target of arriving in 2031.
This mission aims to study the structure and composition of small asteroids, which often pass close to Earth and are potentially dangerous if they fall into the atmosphere.
According to an astronomer from the University of Alicante and leader of the observation team, Toni Santana-Ros, KY26 is most likely composed of solid rock, not a pile of dust or debris. However, other possibilities cannot be completely ruled out until Hayabusa2 arrives at the location.
This discovery also provides new hope for planetary defense research. By carrying out this research, the researchers aim to study prospective asteroids that have the potential to threaten Earth.
“We now know that we can study even the smallest asteroids that could harm Earth, such as the one that crashed into Chelyabinsk, Russia, in 2013,” explained Hainaut.
Apart from being important for Earth’s safety, research on KY26 also opens up new opportunities for near-Earth asteroid exploration and the potential for mining space resources in the future. The results of these observations have been published in journals Nature Communications on September 18, 2025. (Space.com/Z-10)
