Itokawa
A small, peanut-shaped near-Earth asteroid visited by Japan's Hayabusa spacecraft, which brought the first asteroid samples back to Earth.
Itokawa (asteroid 25143) is only about 535 metres long, shaped like a sea otter or a lumpy peanut. Named after the Japanese rocket pioneer Hideo Itokawa, it was visited in 2005 by JAXA's Hayabusa spacecraft. Images showed a surprising world with almost no large craters, smooth gravel-filled lowlands and areas crowded with boulders. Its low bulk density, around 1.9 grams per cubic centimetre, shows it is a rubble pile of reassembled fragments.
Hayabusa's sampling did not go to plan, and the mission suffered engine and other faults, but its capsule landed in Australia in June 2010. Inside were around 1,500 tiny grains, most smaller than a tenth of a millimetre. They were enough to answer a long-standing question: the minerals and oxygen isotopes match LL chondrites, a type of ordinary chondrite. This confirmed that common S-type asteroids are the parents of the most frequently falling meteorites. The grains also showed the thin altered rims produced by space weathering.
You can think of any LL chondrite in a collection, such as Chelyabinsk, which fell in Russia in 2013, as a cousin of Itokawa material. The asteroid itself is too small and faint to see without a large telescope.
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