NASA set to deliver biggest asteroid sample yet: What you need to know

Planet Earth is about to receive a special delivery -- the biggest sample yet from an asteroid. A United States space agency (NASA) spacecraft will fly by Earth on Sunday and drop off what is expected to be at least a cupful of rubble it grabbed from the asteroid Bennu, closing out a seven-year quest. The sample capsule will parachute into the Utah desert as its mothership, the OSIRIS-REx spacecraft, zooms off for an encounter with another asteroid. Scientists anticipate getting about 250g (0.5lb) of pebbles and dust, much more than the teaspoon or so brought back by Japan from two other asteroids. No other country has fetched pieces of asteroids, preserved time capsules from the dawn of our solar system that can help explain how Earth -- and life -- came to be.