Hayabusa2 extended mission
After returning Ryugu samples, Hayabusa2 continued on an extended mission to fly past one asteroid and rendezvous with another by 2031.
After dropping its sample capsule at Earth in December 2020, the Hayabusa2 spacecraft still had fuel and working instruments. JAXA sent it on an extended mission, sometimes called Hayabusa2#, the hash sign standing for 'sharp'.
Its plan was to fly past the small asteroid 2001 CC21 in 2026 and then reach 1998 KY26 in 2031. Observations in 2025 showed 1998 KY26 to be only about 11 metres across, spinning once every five minutes or so. It will be the first visit to such a fast-rotating small asteroid.
Studying 1998 KY26 is relevant to planetary defence, because objects of tens of metres, like the Chelyabinsk meteoroid, are the commonest dangerous size. Their structure, whether solid rock or loose rubble held by tiny forces, determines how they would behave if they hit Earth or were deflected.
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