Astronomers have just revealed new details about asteroid 1998 KY26, the target of Japan’s Hayabusa2 extended mission—and it’s a much tougher challenge than expected.

New observations with ESO’s Very Large Telescope show that the asteroid is only 11 meters wide—almost three times smaller than previously thought. Even more surprising, it spins once every five minutes, making it one of the fastest rotating asteroids ever measured.

This is a big problem. Why? Because Hayabusa2 is scheduled to touch down on the asteroid in 2031. The smaller size and rapid spin will make that maneuver far more complicated—like trying to land on a rock barely bigger than the spacecraft itself, whirling in space.

This will be the first-ever close-up mission to such a tiny asteroid. Studying it could reveal whether it’s a solid chunk of rock or just a loose rubble pile.

The mission could also help scientists better understand hazardous mini-asteroids—the kind that sometimes collide with Earth, like the Chelyabinsk event in 2013.

Hayabusa2 already made history by bringing back samples from asteroid Ryugu in 2020. Now, its final act may be its most daring—trying to “kiss” an asteroid the size of a house, spinning faster than a carnival ride.