China sets out to sample an unusual near-Earth asteroid

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By Dennis Normile, Science. 

Excerpt: Following its successes retrieving lunar samples from both the near and far sides of the Moon, China is planning an encore, sending a probe to snatch material from a near-Earth asteroid. The target of the Tianwen-2 mission, which is expected to launch by the end of the month, is a chunk of rock named 469219 Kamo‘oalewa. It is one of just seven asteroids that fall into a little-understood class known as quasi-satellites of Earth—and it could also be the first known asteroid comprised of lunar material. That hypothesis could be confirmed by laboratory studies of fragments collected by Tianwen-2, which are due to be returned to Earth about 2.5 years after launch. ...Kamo‘oalewa was discovered in 2016 by the Pan-STARRS 1 asteroid survey telescope on Haleakalā in Hawaii. It ...has been in its current orbit for about 100 years and will likely remain there for another 300.... University of Arizona planetary scientist Benjamin Sharkey and colleagues aimed the Large Binocular Telescope...at the object...the telescope picked up a very atypical spectrum...that suggested Kamo‘oalewa is made up of silicates resembling those found in Apollo lunar samples. Among other plausible origins, the asteroid might have been ejected from the Moon’s surface as the result of a collision with some other astronomical object, Sharkey and his team wrote in Communications Earth & Environment in 2021.... 

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