An international team of astronomers, led by Toni Santana-Ros from the University of Alicante, has revolutionized our understanding of the asteroid 1998 KY26. Thanks to observations made with the Gran Telescopio de Canarias, the Very Large Telescope (VLT) of the European Southern Observatory, and Gemini South, it has been discovered that this object is nearly three times smaller and rotates twice as fast as previously thought. Until now, 1998 KY26 was estimated to be about 30 meters in diameter and completed a rotation in 10 minutes. However, new data reveals that it measures only 11 meters and spins on its axis in just five minutes. “The reality of 1998 KY26 is completely different from what was previously known,” explains Santana-Ros, the lead author of the study published in Nature Communications. In fact, the asteroid could fit inside the dome of the VLT itself. This finding is particularly relevant because 1998 KY26 will be the final destination of the extended Hayabusa2 mission from the Japan Aerospace Exploration Agency (JAXA), scheduled for 2031. After its successful encounter with the asteroid Ryugu and the return of samples to Earth, Hayabusa2 is now heading to this small and fast-moving target, becoming the first mission to visit an asteroid of such small dimensions. The smaller size and rapid rotation of 1998 KY26 pose an unprecedented technical challenge for the Japanese spacecraft. “The contact maneuver will be much more difficult than expected,” notes Olivier Hainaut, co-author of the study and an astronomer at ESO in Germany. Until now, all space missions have explored asteroids hundreds or thousands of meters in diameter, so this encounter will open a new window for the study of the smaller bodies in the Solar System. Observations suggest that 1998 KY26 has a bright surface and could be a solid rock fragment, although it is not ruled out that it is made up of adhered debris. “We have never seen an asteroid of this size up close, so we do not know exactly what to expect,” points out Santana-Ros. The team emphasizes that characterizing such a small object from Earth demonstrates the potential of large telescopes for future missions, exploration of near-Earth objects, and even space mining. Additionally, these methods will allow for the identification and study of potentially hazardous smaller asteroids, like the one that impacted Chelyabinsk in 2013. The study of 1998 KY26 not only paves the way for the Hayabusa2 mission but also marks a milestone in the exploration of the smallest asteroids and in planetary protection.