A spacecraft that traveled to a near-Earth asteroid and attempted the unprecedented feat of sampling its surface directly for examination back on Earth looks to have succeeded in its task. The Japan Aerospace Exploration Agency (JAXA) announced November 16 that one of the particle collectors from its Hayabusa probe is indeed loaded with particulate matter from Asteroid Itokawa. At the time of Hayabusa's 2005 encounter with the asteroid, the success of the attempted sample collection was not clear. Its rendezvous with the asteroid was fraught with glitches, including a landing that was initially unrecognized by mission controllers and a projectile gun intended to stir up asteroid dust that did not fire.

In June of this year, though, Hayabusa successfully delivered its payload to Earth, dropping a shielded return capsule over Australia. Of the two collection chambers on board, only one has so far been opened and analyzed, according to Sky & Telescope.

Material scooped out of the first chamber with a special spatula and examined with scanning electron microscopy revealed "about 1,500 grains...and most of them were judged to be of extraterrestrial origin, and definitely from Asteroid Itokawa," according to a JAXA press release. Most of the rocky particles are less than 10 microns in length. (A micron is one millionth of a meter.)

"The minerals are all extremely rare and never found together on Earth," NASA's Michael Zolensky told Sky & Telescope of the particles retrieved by Hayabusa. "But they constitute the major minerals found in some ordinary chondrite meteorites." Researchers investigating the evolution of the solar system covet pristine materials from comets and asteroids, which contain relatively primitive building blocks left over from the formation of the planets. Analysis of such primitives can help unravel the conditions and processes that dominated billions of years ago, when the sun and planets took shape out of a cloud of dust and gas.

Photo: JAXA