Hayabusa 2 Completes Flyby Past Asteroid Torifune

It’s not every day that you get to see a new corner of the solar system. The Japan Aerospace Exploration Agency (JAXA) gave us just such a glimpse, revealing an enigmatic worldlet as it conducted a successful flyby of the asteroid 98943 Torifune.

“On July 5th at 18:35 JST (9:00 UT), the Hayabusa 2 spacecraft was confirmed from ground communications to be operating normally,” says JAXA in a recent press release. “We are pleased to share the following images and scientific data that were successfully obtained of asteroid Torifune.” Images, obtained just 0.6 miles (1 kilometer) from the asteroid, as well as annotated graphics were released in the Japanese-language press conference:

“This is such an amazing and complex image — it shows Torifune to be a contact binary — perhaps the best example that I have ever seen,” says Sara Russell (Natural History Museum London), part of the international science team studying the Ryugu sample. “These [binaries] are formed when two objects collide and stick together, giving insights into how small bodies in the solar system and other stellar systems grow into progressively larger objects and eventually into planets.”

Torifune sports twin lobes of roughly equal size that likely came together in a low-speed impact. Such impacts may have been common in the early solar system. New Horizons' images of Arrokoth show the same bilobed shape, and the Lucy spacecraft's April 2025 flyby revealed another peanut-shaped asteroid, 52246 Donaldjohanson. And the European Space Agency’s Rosetta mission closely inspected a contact binary comet, 67P/Churyumov–Gerasimenko, even landing on its surface.

All instruments were on deck and brought to bear before and during the flyby, including the mission’s Optical Navigation Camera, the Near-Infrared Spectrometer, and the Thermal Infrared Imager. To track the flyby, JAXA’s Usada Deep Space Center and the Misasa Deep Space Station partnered with NASA’s Deep Space Network.

Torifune's surface is also speckled with boulders, reminiscent of the mission’s original target, 162173 Ryugu, and similar to Osiris-REX’s destination, 101955 Bennu. (Those two asteroids were not contact binaries, though, instead shaped like spinning tops, with a wider middle and narrow ends.)

“The boulders come in a variety of shades that may show they have different compositions,” Russell says. “Overall, this image gives us loads to think about, and there is so much information in it that will be studied in detail over the next months and years.”

Discovered by the LINEAR sky survey on February 3, 2001, Torifune was named for Ame-no-torifune in the Japanese origin/creation mythos, which translates as "A god’s ship which can travel at high-speed like a bird, but is also as steady as a rock." Indeed, relative to the spacecraft, the rock was traveling 5 km/s (more than 10,000 mph).

Orbiting the Sun once every 383 days, Torifune is an Apollo-class near-Earth object (NEO) that crosses Earth's orbit. It's about 450 meters (1,500 feet) long — about the size of the longest ship ever constructed, the Seawise Giant. Torifune is also a fast rotator, spinning around every 5 hours. It isn't yet clear how the worldlet obtained a such fast rotation rate.

Extended Mission

The Hayabusa 2 mission explored Ryugu from 2018 to 2019, and returned samples to Earth on December 5, 2020. Then, JAXA approved an extended mission, dubbed Hayabusa 2# (as in ‘sharp,’ like the musical notation). JAXA has hinted at multiple targets that the mission could swing by for closer studies.

Next up for Hayabusa 2 are two Earth flybys, one in December 2027 and another in June 2028. In 2031, the mission will arrive at an asteroid that's rotating ultra-fast, 1998 KY26, which spins around every 10.7 minutes.

JAXA has hinted at other uses for the Hayabusa 2 mission. If 1998 KY26 turns out to be an inactive nucleus of a comet, also sometimes called a "dark comet," the team may use the remaining fuel to approach and perhaps even touch down on the fast-spinning world in a risky maneuver. If it can land, the spacecraft could use its remaining tantalum bullet to create a small crater on the asteroid in an effort reveal its internal composition.

Congrats to the JAXA team on a continuing successful mission for the intrepid Hayabusa 2 spacecraft.