A mosaic image of the asteroid Bennu created by observations made by NASA's OSIRIS-REx spacecraft. (Image credit: NASA/Goddard/University of Arizona)

On Sept. 30, NASA formally concluded OSIRIS-REx, the historic first U.S. mission to pluck a pristine piece of an asteroid and deliver it safely back to Earth.

The van-sized OSIRIS-REx spacecraft — whose name is short for Origins, Spectral Interpretation, Resource Identification, Security-Regolith Explorer — visited and sampled Bennu , an ancient space rock holding pristine remnants from the dawn of our solar system more than 4.5 billion years ago. Among those cosmic relics are raw organic building blocks , the kind that may have seeded life on Earth.

"I have known this day was coming for a long time, but it is still difficult to see it arrive," OSIRIS-REx Principal Investigator Dante Lauretta, who's based at the University of Arizona, said in a post on LinkedIn .…