Japan’s Hayabusa2 Spacecraft's Next Target is Smaller and Faster than Expected

Japan’s Hayabusa2 Spacecraft's Next Target is Smaller and Faster than Expected

Astronomers have discovered that the next target for Japan’s Hayabusa2 spacecraft, the asteroid 1998 KY26, is almost three times smaller than previously thought, and spinning much faster than expected. This study was conducted using the European Southern Observatory’s Very Large Telescope (VLT), and its results offer important new information for the upcoming mission, just six years out from the spacecraft’s encounter with this tiny asteroid. 

“We found that the reality of the object is completely different from what it was previously described as,” says astronomer Toni Santana-Ros, a researcher from the University of Alicante, Spain, who led a study on 1998 KY26 published today in Nature Communications. The new observations, combined with previous radar data, have revealed that the asteroid is just 11 meters wide, meaning it could easily fit inside the dome of the VLT unit telescope used to observe it. It is also spinning about twice as fast as previously thought: “One day on this asteroid lasts only five minutes!" he says. Previous data indicated that the asteroid was around 30 meters in diameter and completed a rotation in 10 minutes or so. 

"The smaller size and faster rotation now measured will make Hayabusa2’s visit even more interesting, but also even more challenging,” says co-author Olivier Hainaut, an astronomer at ESO in Germany. This is because a touchdown maneuver, where the spacecraft ‘kisses’ the asteroid, will be more difficult to perform than anticipated.

1998 KY26 is set to be the final target asteroid for the Japanese Aerospace eXploration Agency (JAXA)'s Hayabusa2 spacecraft. In its original mission, Hayabusa2 explored the 900-meter-diameter asteroid 162173 Ryugu in 2018, returning asteroid samples to Earth in 2020. With fuel remaining, the spacecraft was sent on an extended mission until 2031, when it is set to encounter 1998 KY26, aiming to learn more about the smallest asteroids. This will be the first time a space mission encounters a tiny asteroid—all previous missions visited asteroids with diameters in the hundreds or even thousands of meters. 

1998 KY26 is a nearly spherical sub-kilometer asteroid, classified as a near-Earth object of the Apollo group. It measures approximately 11 meters (40 feet) in diameter and is a fast rotator, having a rotational period of only 5.35 minutes. It was first observed on June 2, 1998, by the Spacewatch survey at Kitt Peak National Observatory when it passed 800,000 kilometers (half a million miles) away from Earth (a little more than twice the Earth–Moon distance).

Credit: European Southern Observatory (ESO)
Directed by: Angelos Tsaousis and Martin Wallner
Editing: Angelos Tsaousis
Written by: Amy Briggs and Sean Bromilow
Footage and photos: ESO, Luis Calçada, Angelos Tsaousis, Martin Kornmesser, P. Das et al., K. Noll et al., Gerhard Hüdepohl, Daniele Gasparri
Scientific consultant: Paola Amico, Mariya Lyubenova
Duration: 1 minute, 18 seconds
Release Date: Sept. 18, 2025

#NASA #ESO #Astronomy #Space #Science #Asteroid #NEO #1998KY26 #Hayabusa2 #はやぶさ2 #Spacecraft #JAXA #宇宙航空研究開発機構 #Japan #日本 #SolarSystem #Cosmos #Universe #VLT #ParanalObservatory #Chile #SouthAmerica #Europe #SpaceExploration #STEM #Education #HD #Video