An unmanned Air Force space plane steered itself to a landing early Saturday at a California military base, capping a 15-month clandestine mission.
An unmanned Air Force space plane steered itself to a landing early Saturday at a California military base, capping a 15-month clandestine mission.

An unmanned Air Force space plane steered itself to a landing early Saturday at a California military base, capping a 15-month clandestine mission.