Hayabusa (Japanese: はやぶさ, "Peregrine falcon") was a robotic spacecraft developed by the Japan Aerospace Exploration Agency (JAXA) to return a sample of material from a small near-Earth asteroid named 25143 Itokawa to Earth for further analysis.

After arriving at Itokawa, Hayabusa studied the asteroid's shape, spin, topography, color, composition, density, and history.

Technically, Hayabusa was not designed to "land"; it simply touches the surface with its sample capturing device and then moves away.

The spacecraft's xenon ion engines (four separate units), operating near-continuously for two years, slowly moved Hayabusa toward a September 2005 rendezvous with Itokawa.

After this the spacecraft moved closer to the surface (the "home position"), and then approached the asteroid for a series of soft landings and for the collection of samples at a safe site.

Autonomous optical navigation was employed extensively during this period because the long communication delay prohibits Earth-based real-time commanding.

After a few months in proximity to the asteroid, the spacecraft was scheduled to fire its engines to begin its cruise back to Earth.

Hence 'operation of ion engines for more than 1000 hours' is an achievement that gives a full score of 100 points, and the rest of the milestones are a series of world's first-time experiments built on it.

This solar-powered vehicle was designed to take advantage of Itokawa's very low gravity by using an internal flywheel assembly to hop across the surface of the asteroid, relaying images from its cameras to Hayabusa whenever the two spacecraft were in sight of one another.

Hayabusa helped solve this problem by bringing back pristine samples from a specific, well-characterized asteroid.

Hayabusa bridged the gap between ground observation data of asteroids and laboratory analysis of meteorite and cosmic dust collections.

It allowed JAXA to further test its technologies in the fields of ion engines, autonomous and optical navigation, deep space communication, and close movement on objects with low gravity among others.

However, at 01:50 UTC (10:50 am JST) on 4 November, it was announced that due to a detection of an anomalous signal at the Go/NoGo decision, the descent, including release of Minerva and the target marker had been canceled.

The project manager, Junichiro Kawaguchi, explained that the optical navigation system was not tracking the asteroid very well, probably caused by the complex shape of Itokawa.

After that, Hayabusa backed off to a higher position, then descended again to 500 m and released one of the target markers into space to test the craft's ability to track it (this was confirmed).

Ground control sent a command to abort and ascend, and by the time the communication was regained, the probe had moved 100 km away from the asteroid.

It was initially thought that this time, the sampling device was activated;[43] however, later analysis decided that this was probably another failure and that no pellets were fired.

On 4 December, as an emergency measure, xenon propellant from the ion engines was blown to correct the spin, and it was confirmed successful.

[49][50] On 7 March 2006, JAXA announced[51][52] that communication with Hayabusa had been recovered in the following stages: On 23 January, the beacon signal from the probe was detected.

On 1 June, Hayabusa project manager Junichiro Kawaguchi reported[53] that they confirmed two out of four ion engines were working normally, which would have been sufficient for the return journey.

[57] On 29 October, JAXA reported that the first phase of trajectory maneuver operation had finished and the spacecraft was now put in a spin-stabilized state.

[58] On 4 February 2009, JAXA reported success in reignition of the ion engines and starting the second phase of the trajectory correction maneuver to return to Earth.

[75] The heat-shielded capsule made a parachute landing in the South Australian outback while the spacecraft broke up and incinerated in a large fireball.

[76] An international team of scientists observed the 12.2 km/s entry of the capsule from 11.9 km (39,000 ft) on board NASA's DC-8 airborne laboratory, using a wide array of imaging and spectrographic cameras to measure the physical conditions during atmospheric reentry in a mission led by NASA's Ames Research Center, with Peter Jenniskens of the SETI Institute as the project scientist.

[77][78] Since the reaction control system no longer functioned, the 510 kilograms (1,120 lb) space probe re-entered the Earth's atmosphere similar to the approach of an asteroid along with the sample re-entry capsule, and, as mission scientists expected, the majority of the spacecraft disintegrated upon entry.

[81] After confirming that the explosive devices used for parachute deployment were safe, the capsule was packed inside a double layer of plastic bags filled with pure nitrogen gas to reduce the risk of contamination.

[82] The capsule and its heat shield parts were transported to Japan by a chartered plane and arrived at the curation facility at the JAXA/ISAS Sagamihara Campus on 18 June.

[85] On 16 November 2010, JAXA confirmed that most of the particles found in one of two compartments inside the Hayabusa sample return capsule came from Itokawa.

[87] After further studying the analysis results and comparison of mineral compositions, most of them were judged to be of extraterrestrial origin, and definitely from the asteroid Itokawa.

In 2013 JAXA announced that 1500 extraterrestrial grains had been recovered, comprising the minerals olivine, pyroxene, plagioclase and iron sulfide.