Hayabusa2 probe skims asteroid in Japan's planetary defense test

Hayabusa2 probe skims asteroid in Japan's planetary defense test

A fridge-sized Japanese space probe has completed a high-speed flyby of a near-Earth asteroid, serving as a trial for technology designed to protect Earth from potentially dangerous space rocks. The spacecraft, Hayabusa2, skimmed the asteroid Torifune on Sunday, July 5, 2026.

The Japan Aerospace Exploration Agency (JAXA) confirmed that the probe conducted the flyby at approximately 6:30 p.m. Japan time. A JAXA spokeswoman stated at 6:35 p.m. (0935 GMT) that the spacecraft was working normally.

Moving at a relative speed of 5 kilometers per second — or more than 18,000 kilometres per hour — Hayabusa2 was not intended to collide with the asteroid. Instead, the mission aimed to test whether scientists could precisely control a probe's trajectory at high speeds, a capability necessary if a spacecraft ever needs to deflect a threatening asteroid.

The precision required for the maneuver was extreme. Yuya Mimasu of JAXA likened the difficulty to trying to shoot through a one-yen coin somewhere within the area stretching from Okinawa to Hokkaido, referencing the southernmost and northernmost islands of Japan.

Planetary Defense and Reconnaissance

The mission follows a 2022 NASA operation that deliberately crashed a spacecraft into the 160-metre-wide Dimorphos asteroid to successfully alter its orbit. While Hayabusa2 did not perform a kinetic impact, it acted as a test for rapid reconnaissance. Such missions could determine the physical properties of a space rock before an interception attempt.

Cameras on the probe recorded the asteroid's temperature, texture, and geographical features. According to Patrick Michel, a project scientist at the European Space Agency, this data is vital because the effectiveness of an impact depends on whether an asteroid behaves like a sponge or a very solid material.

Michel noted that only spacecraft images can reveal if a surface consists of sand beaches, boulder fields, or bare rock. He added that because near-Earth asteroids vary in shape, size, and internal properties, each new image makes us better prepared.

The Nature of Torifune

Torifune, also known as 2001 CC21 and named after a deity from Japanese mythology, is roughly 450-metre-wide. JAXA's Satoshi Tanaka noted the asteroid is somewhat similar to Itokawa, the target of the original Hayabusa mission, though much remains unknown about it.

The operation carried inherent risks due to uncertainties regarding the asteroid's dimensions. Michel suggested Torifune could be a contact binary, where two separate bodies merged at low velocities, similar to comet 67P/Churyumov-Gerasimenko or the Kuiper belt object Arrokoth.

Extended Mission Timeline

The flyby is part of an extended mission that began in 2020. Launched in 2014, Hayabusa2 previously traveled 300 million kilometres to the asteroid Ryugu, which means dragon palace in Japanese. The probe gathered samples from Ryugu and returned them to Earth six years after its launch, providing clues about the solar system's state 4.6 billion years ago.

Since completing its primary objectives, the spacecraft has observed exoplanets and zodiacal light, despite briefly entering a protective safe mode last year.

The probe is now heading toward its final target. In 2031, Hayabusa2 is expected to attempt a rendezvous with asteroid 1998 KY26. This target is only 11 metres wide, which would make it the smallest asteroid ever visited. The spacecraft may attempt to land on the object to gather detailed data.

JAXA is scheduled to hold a news conference on Monday, July 6, to explain the results of the Torifune operation in detail and potentially release captured images.