Success! The Hayabusa space explorer has picked up dust from the Itokawa asteroid, from which it returned in June after a seven-year mission. The grains are the first materials ever returned to Earth from an asteroid.
Researchers at the Japan Aerospace Exploration Agency (JAXA) announced on 16 November that analysis of the mineral compositions of around 1,500 micrometre-sized grains from Hayabusa’s recovery capsule showed that almost all the dust was extra-terrestrial.
Tell-tale signs came from the composition of the minerals olivine, pyroxene, and plagioclase in the grains, which were very different to the compositions seen on Earth, explained Trevor Ireland, an Australian scientist who was involved in the preliminary investigation of Hayabusa’s returned sample after its capsule was recovered in Woomera in June (pictured right). The mineral troilite (iron sulfide) was also spotted – which is not seen on Earth, but is common in chondrites (ancient stony meteorites).
Researchers had hoped for larger peanut-sized asteroid rocks. But after the US$230 million probe’s troubled journey to and from Itokawa, the presence of even tiny asteroid particles is a triumph for Hayabusa, which has inspired further near-Earth asteroid exploration efforts.
Picture credit: JAXA