What We Know About the Air Force's Secret Space Drone

The U.S. military is preparing to launch its super-secret autonomous space drone for a fourth mission. No one will say precisely what the X-37B does on its orbital missions, which typically last more than a year, but the Air Force Space Command says the latest mission will move beyond prior systems testing, which involved research on maneuvering, durability and other technologies that help the drone fly and land itself. The latest mission will involve research with NASA, which says it's testing "advanced materials" in zero gravity and a new type of propulsion system. (Video by Alan Jeffries) (Source: Bloomberg)