Sample return missions are becoming increasingly in vogue, as evidenced by NASA’s OSIRIS-REx mission and China’s current Chang’e 5 drilling operation on the moon. But they aren’t easy. In February 2019, Hayabusa2 landed on the surface and fired two small bullets into the asteroid to stir up a cloud of particles from which the sample arm could collect debris. It fired a larger projectile in April that same year, diving down to the surface a couple months later to retrieve even more ejected material.
Whereas the first Hayabusa mission was only able to bring back a millionth of a gram through this approach, there’s optimism Hayabusa2 will bring back much more. “I am proud of this success, even though I don’t know yet that the re-entry [of the sample capsule] will be successful,” says Eri Tatsumi, a planetary scientist at the University of La Laguna in Spain who has been