The Atlas 5 rocket lifted off at 9:49 am today and roared away into a clear sky over Vandenberg Air Force Base.
All systems were going well when the launch webcast concluded about five minutes into the flight, as is customary during such missions.
The satellite dubbed NROL-79 is described only as a national security payload for the NRO.
The once-secret office operates an array of intelligence-gathering satellites.
The launch was conducted by United Launch Alliance, a joint venture of Lockheed Martin and Boeing, and the Air Force's 30th Space Wing.