The booster and Centaur upper stage of a United Launch Alliance Atlas V vent gaseous propellant during a “wet dress rehearsal” test at Space Launch Complex 41 on Florida’s Cape Canaveral Air Force Station. The rocket will boost NASA’s OSIRIS-REx spacecraft on its way to the asteroid Bennu. Short for Origins, Spectral Interpretation, Resource Identification, Security-Regolith Explorer, OSIRIS-REx is to survey the asteroid closely before taking a sample from its surface and sending that small sample back to Earth for study.

Targeted for liftoff Sept. 8, 2016, OSIRIS-REx will be the first U.S. mission to sample an asteroid, retrieve at least two ounces of surface material and return it to Earth for study. The asteroid may hold clues to the origin of the solar system and the source of water and organic molecules found on Earth. Photo credit: NASA/Kim Shiflett