A fridge-sized probe, a spinning double rock, and one of the fastest close passes ever flown.
How do you thread a fridge-sized spacecraft past a spinning mountain of rock at more than 18,000 kilometres per hour and live to send back the photos? Welcome, fellow sky-watchers. On 5 July 2026, Japan’s Hayabusa2 probe did exactly that, sweeping past a strange double-lobed asteroid called Torifune.
Stay with us to the end, and you will see why this brief, breathtaking encounter matters far beyond one striking picture, both for the science of small worlds and for the quiet work of keeping our own planet safe.
The direct answer
On 5 July 2026, the Japanese probe Hayabusa2 flew past near-Earth asteroid 98943 Torifune at a relative speed of 5 kilometres per second, over 18,000 kilometres per hour. It was one of the fastest close asteroid flybys ever attempted, staged to test the pinpoint navigation that future planetary-defence missions will need.
What did the Hayabusa2 Torifune flyby reveal?
The Hayabusa2 Torifune flyby, on 5 July 2026, gave us our first close look at 98943 Torifune and confirmed its odd two-lobed shape. Torifune is a near-Earth asteroid about 450 metres across, roughly the length of the Empire State Building, and at the moment of the pass it sat some 100 million kilometres from Earth. Once known by the provisional label 2001 CC21, it circles the Sun every 383 days and turns on its axis once every five hours.
How close did Hayabusa2 come to Torifune?
Hayabusa2 was reported to have swept within about 10 kilometres of Torifune’s centre, while JAXA’s pre-flyby plan had aimed for a pass around one kilometre away, at a relative speed of 5 kilometres per second, more than 18,000 kilometres per hour. That speed is hard to picture, so try this: at 5 kilometres a second, the probe crossed the whole 450-metre length of the asteroid in under a tenth of a second. One team scientist had described the manoeuvre as “risky” (our translation) beforehand, given how little was known about the conditions around the rock.
Why do scientists call Torifune a two-headed asteroid?
Torifune earned its two-headed nickname by looking like two rocks fused into one, and scientists think that is very likely what it is. The favoured explanation is a contact binary: two smaller bodies that drifted together over long ages and gently stuck, forming a single peanut-shaped object. Torifune belongs to the Apollo group of near-Earth asteroids, a family whose paths cross Earth’s own orbit, cousins of the rocky bodies that fill the main asteroid belt between Mars and Jupiter.
What did Hayabusa2’s cameras show?
Hayabusa2’s cameras showed a weathered, rocky surface built mainly from silicate minerals such as pyroxene and olivine. During the approach the probe used its optical navigation camera, the ONC-T, to capture the first close-up of Torifune, then beamed it home to mission control. It also turned a mid-infrared camera, the TIR, on the asteroid to read surface temperature, thermal inertia and roughness. Those thermal maps came out colder in the shadows and warmer where sunlight struck the surface, a clue to what the rock is made of and how it holds heat. Most of the science data still has to reach Earth over the coming weeks.
How does the flyby help protect Earth from asteroids?
The flyby helps protect Earth by rehearsing the pinpoint steering a real asteroid-deflection mission would demand. This close pass was not in Hayabusa2’s original plan; it was added as part of the extended mission. JAXA’s main goal was to prove ultra-precise orbital-guidance technology, the kind you would need to nudge a dangerous asteroid off a collision course, in the spirit of NASA’s DART planetary-defence test. The pass also tested the craft’s autonomous navigation, which held a precise course at very high speed with no human hand on the controls. Precise asteroid tracking like this feeds wider mission design too; researchers have even shown how asteroid orbits can chart faster routes to Mars.
What has Hayabusa2 achieved so far?
Hayabusa2 has already pulled off one of the great sample-return feats in space history. Launched in December 2014, its first job was to collect material from asteroid Ryugu, a mission it completed in full. The probe reached Ryugu in 2018, studied it for about a year and a half, and scooped up 5.4 grams of surface and near-surface rock, helped by a small explosive charge that exposed fresh material. In December 2020 it dropped the sample capsule into the Australian desert. Those grains later let scientists rebuild chapters of Solar System history, even revealing that Ryugu carries all five of the nucleobases that make up DNA and RNA. With roughly 30 of its original 66 kilograms of xenon fuel still aboard, the probe pressed on into deep space under an extended mission nicknamed Hayabusa2#, adding studies of exoplanet transits and the faint glow of zodiacal light.
| Target | Encounter | Key outcome | Date |
|---|---|---|---|
| Ryugu | Landing and sample return | 5.4 g of rock returned to Earth; all five DNA and RNA nucleobases later found in the dust | 2018 to 2020 |
| Torifune (about 450 m) | High-speed flyby | First close images; suspected contact-binary shape imaged; precision-guidance test passed | July 2026 |
| 1998 KY26 (about 11 m) | Planned orbit and landing | Would become the smallest asteroid ever visited by a spacecraft | 2031 (planned) |
Where is Hayabusa2 heading next?
Hayabusa2’s final target is the tiny asteroid 1998 KY26, which it should reach in 2031. At just 11 metres wide, about the size of the rock that blew up over Chelyabinsk, Russia, in 2013, it could become the smallest asteroid ever visited by a spacecraft, and it spins wildly, once every ten minutes or so. There is a further twist: 1998 KY26 was recently sorted into the so-called dark comets, a puzzling new class of objects flagged after the interstellar visitor Oumuamua turned up in 2017, the same family of cosmic wanderers as the interstellar comet 3I/ATLAS we followed closely. When it arrives, Hayabusa2 will orbit the little body before trying an actual landing, hoping to lay bare the structure and make-up of these small, elusive fragments of the Solar System.
The bigger picture
Torifune will never be a household name, and yet this quick flyby carries real weight. In a single high-speed pass, Hayabusa2 caught a rare double-lobed world on camera, gathered thermal and mineral clues about its make-up, and, above all, proved it can steer with the accuracy any future asteroid-deflection mission will rely on. The next time you read that a small asteroid has been spotted heading our way, remember that dress rehearsals like this one are how humanity learns to answer calmly rather than fearfully.
This article was written specifically for you by FreeAstroScience.com, where we explain complex scientific principles in simple terms. Come back and visit us again, and whatever you do, never turn off your mind, for the sleep of reason breeds monsters.
Gerd Dani
Frequently asked questions
What is asteroid Torifune?
Torifune is a near-Earth asteroid roughly 450 metres wide, catalogued as 98943 Torifune and formerly labelled 2001 CC21. It belongs to the Apollo group, circles the Sun every 383 days, and spins once every five hours. Scientists suspect it is a contact binary, two rocks fused into one body.
How fast did Hayabusa2 fly past Torifune?
Hayabusa2 swept past Torifune at a relative speed near 5 kilometres per second, more than 18000 kilometres per hour. At that pace the probe crossed the full length of the asteroid in under a tenth of a second. JAXA planned a pass around one kilometre away, though the craft ended near ten kilometres out.
Why is Torifune called a two-headed asteroid?
Torifune looks like two rocks stuck together, and it probably is one. Scientists think it is a contact binary, formed when two smaller bodies drifted together and gently fused over long spans of time. The nickname two-headed captures that twin-lobed shape, which the flyby images from Hayabusa2 show clearly.
What is Hayabusa2 doing after Torifune?
After Torifune, Hayabusa2 heads for tiny asteroid 1998 KY26, with arrival expected in 2031. That rock spans only 11 metres and spins once every ten minutes. The probe will orbit it, then try a landing, making 1998 KY26 the smallest asteroid ever visited by a spacecraft.
Did Hayabusa2 collect samples from Torifune?
No, Hayabusa2 did not collect samples from Torifune. The flyby was a fast reconnaissance pass, not a touchdown, so the probe only photographed the asteroid with its optical and infrared cameras. Sample collection happened earlier at asteroid Ryugu, whose 5.4 grams of dust returned to Earth in December 2020.
Sources
- Focus.it, reporting on JAXA’s Hayabusa2 mission: “L’asteroide a due teste sfiorato a una velocita vertiginosa: l’ultima impresa di Hayabusa2”, July 2026. Image data credited to JAXA.
