Two asteroid flybys, one weekend: what the first close-up images of Kamoʻoalewa and Torifune reveal

About the asteroid: Kamoʻoalewa (designated 469219, also known as 2016 HO3) is a near-Earth asteroid and a quasi-satellite of Earth — a so-called "minimoon" that orbits the Sun in a 1:1 resonance with Earth, keeping it relatively nearby but far beyond the Moon's orbit . The new images revealed it is smaller than expected, which mission scientists say will make the sample-return operation "far more difficult" than earlier Japanese and American missions .

Flyby details: Tianwen-2 launched on May 28, 2025 aboard a Long March 3B rocket . After about 400 days of travel, the spacecraft performed its rendezvous maneuver in June 2026 and made its close approach around July 4, 2026 . The spacecraft is now in orbit around the asteroid and will scout for a sampling site before attempting to collect surface material .

Next target: After collecting samples from Kamoʻoalewa, Tianwen-2 will return them to Earth (expected in 2027 via an atmospheric-entry capsule) and then continue to explore a main-belt comet .

Hayabusa2 at Torifune: a snowman asteroid at 5 km/s

The image: On July 5, 2026, Hayabusa2 flew past Torifune and returned images revealing a two-lobed, "snowman-like" shape — sometimes described as a peanut-shaped or contact-binary asteroid . JAXA released the close-up image taken just a second before closest approach, showing clear structural detail .

About the asteroid: Torifune (98943, also designated 2001 CC21) is an S-type (stony) near-Earth asteroid roughly 450 meters in diameter . At the time of the flyby it was about 100 million km from Earth .

Flyby details: Hayabusa2 flew past at a relative speed of 5 km/s (about 18,000 km/h) and a closest approach of about 800 meters to 1 km — one of the closest asteroid flybys ever attempted by any spacecraft . The flyby was a high-speed, non-stop pass; the spacecraft did not slow down or orbit. The precision navigation required was extreme, and the mission served as a test of whether such a probe could accurately intercept a small, fast-moving asteroid for future planetary defense scenarios .

Next target: After the Torifune flyby, Hayabusa2 (on its extended mission, called Hayabusa2#) will perform Earth swing-bys in 2027 and 2028, then proceed to rendezvous with the tiny, fast-rotating asteroid 1998 KY26, scheduled for arrival in 2031 .

Broader significance for asteroid exploration

• Planetary defense rehearsal: Hayabusa2's Torifune flyby was explicitly designed to test high-speed precision approach and navigation — the same skills needed to intercept and deflect a potentially hazardous asteroid. JAXA has stated the flyby served as "an additional technology demonstration contributing to Planetary Defense" .
• Sample-return challenge: Tianwen-2's discovery that Kamoʻoalewa is smaller than anticipated underscores how little we know about these objects before arrival, and how adaptable sample-return techniques must be . The sampling operation is expected to be "far more difficult" than earlier missions because of the asteroid's unexpectedly diminutive size .
• Two approaches to asteroid study: The pair of visits illustrates two complementary strategies — a sample-return rendezvous (Tianwen-2, slow and close, orbiting the target) versus a high-speed reconnaissance flyby (Hayabusa2, fast and targeted, passing at 5 km/s) — both yielding valuable scientific and engineering data.
• Rare close-up data: Before these missions, both Kamoʻoalewa and Torifune were only known as faint points of light in telescopes. The new images provide the first resolved shapes, sizes, surface properties, and compositional clues for these objects .