JAXA's Hayabusa2 spacecraft technically finished its primary job years ago. It visited the asteroid Ryugu, collected samples from its surface, and delivered them to Earth in a capsule that landed in the Australian outback in December 2020. Since then, with fuel and instruments still functional, JAXA has kept it flying on an extended mission, and this fortnight that mission reached a new target: a flyby of the near-Earth asteroid Torifune.
Unlike the Ryugu visit, there's no sample return involved this time. Hayabusa2 doesn't have the fuel or hardware left to attempt another landing and collection sequence. What it can do is fly close enough to capture images and instrument readings, gathering data on Torifune's shape, surface composition and rotation that would otherwise require a dedicated mission to obtain.
It's a useful reminder of how spacecraft economics actually work. Building and launching a probe to a near-Earth asteroid is enormously expensive; getting extra science out of one that's already up there, already working, and already most of the way to its next target is comparatively cheap. Extended missions like this one are how space agencies stretch a single launch budget across multiple scientific targets, and they've produced some of the more efficient science returns in the field, from Voyager's ongoing interstellar readings to Cassini's Saturn moon flybys years after its original mission plan ended.
Torifune is a small, relatively obscure object compared to Ryugu, and this flyby won't generate headlines the way the sample return did. But it's exactly the kind of unglamorous, low-cost science that adds up over a mission's lifetime, and it's a sign that Hayabusa2 still has useful work left in it.