A NASA spacecraft has returned asteroid samples that hold not only the pristine building blocks for life but also the salty remains of an ancient water world.

Tuesday evening marked another NASA milestone: A spacecraft called OSIRIS-REx touched an asteroid, called Bennu, and collected a sample for return to Earth! Over the past year, OSIRIS-REx has been orbiting Bennu and taking increasingly detailed images to find a site. When the mission was originally developed, it was assumed that Bennu would be mostly smooth, with lots of regolith (“dirt”) and perhaps some rocks. How does NASA know if they collected enough material to return to Earth? This is pretty cool science: once back in orbit around Bennu, OSIRIS-REx will extend the TAGSAM arm laterally out to the side of the spacecraft and spin the spacecraft.