Japan Just Ran the Tightest Asteroid Flyby Ever Attempted
On July 5, JAXA’s Hayabusa2 probe flew past a near Earth asteroid closer than any spacecraft has managed before it, moving at a speed most of us will never process.
How Close Is Too Close
Hayabusa2 passed within 400 meters of asteroid Torifune’s surface, 744 meters from its center, moving at roughly 18,000 kilometers an hour. JAXA had planned for a pass around 800 meters from the center. The probe beat that by more than half. JAXA scientist Yuya Mimasu put it plainly: this flyby “passed the closest” of any mission of its kind, anywhere. The previous record belonged to a Chinese probe, which came within 770 meters of an asteroid’s surface, according to Japan’s Nikkei business daily.
A Rock Shaped Like a Snowman
Torifune is about 450 meters wide and used to just be a designation, 2001 CC21, before JAXA gave it a name pulled from Japanese mythology. The images Hayabusa2 sent back showed two lobes stuck together, most likely two separate bodies that drifted into each other and stayed put. JAXA scientist Makoto Yoshikawa said the successful pass proves the agency now has the technology to intentionally collide a spacecraft with a small asteroid, the same kind of maneuver NASA tested with its DART mission in 2022.
Not Just a Photo Op
Hayabusa2 already did the hard part of its job years ago. It launched in 2014, reached asteroid Ryugu in 2018, and brought samples home in December 2020. Everything since has been extra. This flyby tested whether a spacecraft can track and pass a fast moving asteroid with almost no margin for error, the exact skill needed if a real asteroid ever had to be knocked off course.
Next Stop: Something Tiny
Hayabusa2 isn’t done. After two Earth gravity assists in 2027 and 2028, it’s set to reach a much smaller target, asteroid 1998 KY26, in 2031. That asteroid is only around 11 meters across, barely bigger than the probe itself.
