Hayabusa: the comeback mission that brought home the first asteroid sample

A solar flare, failed reaction wheels, a fuel leak and a lost mini-lander — and how JAXA still got a capsule of Itokawa dust to Australia.

Published 2026-10-23

Few spacecraft have survived as many setbacks as JAXA's Hayabusa. It became the first mission to return an asteroid sample to Earth — after almost everything that could go wrong did.^[5]

A change of target

The mission, then called MUSES-C, originally aimed for asteroid 4660 Nereus. A July 2000 failure of Japan's M-V rocket delayed the launch and put Nereus out of reach, so the team chose a new target: the asteroid that would become Itokawa.^[5]

Launch and a record solar flare

Hayabusa launched on May 9, 2003, on an M-V rocket from the Uchinoura Space Center.^[5] It was driven by xenon ion engines that ran nearly continuously for two years. In 2003 an enormous solar flare damaged its solar cells, which reduced power and pushed its arrival back from June to September 2005.^[5]

Trouble at the asteroid

Two of Hayabusa's reaction wheels, which point the spacecraft, failed in 2005 — one on July 31 and one on October 2 — so controllers had to steer with thrusters.^[5] On November 12, the tiny 591-gram MINERVA hopping lander was released at the wrong moment, while the probe was rising, and drifted away into space.^[5]

Hayabusa landed on Itokawa on November 19, 2005, and tried again on November 25.^[5] Its sampling projectile probably never fired, but the touchdowns still kicked up a small amount of dust into the collector.^[5][1] Soon after, a thruster fuel leak sent the craft into safe mode, and on November 27 it suffered a power outage.^[5]

Limping home

When its ion engines ran into trouble too, engineers in November 2009 combined the ion source of one engine with the neutralizer of another to keep thrusting.^[5] On June 13, 2010, Hayabusa released its capsule, which parachuted down near Woomera in South Australia; the spacecraft itself also re-entered the atmosphere.^[5]

The payoff

On November 16, 2010, JAXA confirmed that particles in the capsule came from Itokawa; electron-microscope analysis identified about 1,500 rocky grains.^[5]

Numbered citations link to the sources list on the Itokawa overview page.