The next phase in NASA’s exploration of asteroids begins today with the launch of the OSIRIS-REx mission. This probe will travel millions of miles through space to reach an asteroid called Bennu, at which time it will take a sample of the asteroid and return it to Earth. You can watch this mission kick off live later today (September 8th).The asteroid Bennu (technically called 101955 Bennu) is not particularly remarkable on its own — it’s a carbonaceous asteroid (the most common type) that is almost 500 meters (a third of a mile) in diameter. The only remarkable thing is that its orbit takes it very close to Earth. In fact, its orbit crosses Earth’s, and there’s a small chance (roughly 1 in 2,700) that it could hit us in the 22nd century. Its close proximity makes it a good target for the OSIRIS-REx mission.The launch is currently scheduled for 7:05 PM Eastern, but the NASA coverage will go live at 4:30 PM on the NASA TV stream. The OSIRIS-REx probe will be launched on an Atlas-V rocket operated by ULA. The trip to rendezvous with Bennu will take several years, at which time the spacecraft will begin a comprehensive 505-day surface mapping mission. This will help NASA choose a location for the next step.The ultimate goal of this launch is to get a sample of an asteroid back to Earth that hasn’t been scorched by falling through the atmosphere in the normal way. OSIRIS-REx will descend to within 5 meters of the asteroid and extend a sampling arm that is designed to scoop up as much as 4.4 pounds of regolith from the surface. The sample arm has a built-in 5-second timer that ensures the probe will back away to avoid a collision.The sample should be returned to Earth in 2023, giving scientists a chance to examine unspoiled samples of primordial material from the early solar system. Asteroids like Bennu are believed to contain the same organic molecules that were found on planets like Earth when they formed — the same molecules that eventually gave rise to life. Studying Benuu could give us a glimpse into your own past. It all starts with today’s launch.