Slowly pulling alongside a space rock the size of several typical city blocks, a Japanese probe is preparing to begin scooping the first dusty samples of material from the surface of an asteroid this fall for an eventual return to Earth. Japan's Hayabusa spacecraft is halfway through a four-year $100 million mission to chase down a small celestial target, retrieve pieces of its rocky crust, and return them safely to Earth in a capsule designed to survive the intense heat as it enters the atmosphere and parachutes to a safe landing. Formerly known as MUSES-C, the Hayabusa craft was launched...