On September 8, 2016, the Osiris-Rex spacecraft will rise on a tongue of fire. Leaving Earth on a seven-year mission to snatch part of an ancient asteroid and carry it home. Its target is Bennu, a diamond shaped clump of rubble a quarter mile wide. Asteroids like Bennu were the building blocks of the early solar system, 4.5 billion years ago. Most of these chunks of primordial stuff merged long ago in violent collisions to shape the young Earth and other planets. But Bennu survived, pushed and prodded by the gravity of the planets. Today, Bennu has a regular, 14-month orbit, which swings it close to Earth every six years. But sunlight warms the surface of the asteroid, gradually shifting its orbit in a way that could eventually threaten the Earth. Osiris Rex will take two years to reach Bennu, then spend a year mapping its surface. In July, 2020, the spacecraft will pick a spot, and descend. And try to steal a chunk of the primordial past for humans to study for decades to come. An 11-foot arm unfolds and extends. The spacecraft drops, and briefly touches the asteroid. A puff of nitrogen blows a few ounces of ancient dust from the surface. A cosmic high five, before the spacecraft retreats to safety. The sample is weighed and stowed in a fireproof capsule for the two-year cruise back to Earth. As it approaches home, Osiris-Rex will jettison the sample. Gravity will do the rest. If all goes as planned, the capsule will fall through the atmosphere, open its parachute, and land in the Utah desert on September 24, 2023. A handful of matter retrieved from the dawn of the solar system. Atoms, separated at birth, returned for study after 4.5 billion years of wandering. Future missions might visit another nearby asteroid. A larger spacecraft with robotic arms and legs could straddle a 20-ton boulder, grapple it and tow it away. Then carry it back to orbit the moon, within reach of Earth and its astronauts. Another step in understanding the birth of our solar system and the world on which we live. And perhaps, a clue to protecting our blue and green planet from an asteroid that may, one day, veer too close to home.