T-00:02.7	Engine Start
The Russian-built RD-180 engine rumbles to life and builds to 74 percent thrust. A health check of eight engine parameters is performed by the rocket's onboard computer a half-second before liftoff.
T+00:00	Liftoff
The sixth and final flight for Atlas 3 begins as the rocket is released from pad 36B at Cape Canaveral Air Force Station, Florida.
T+02:59	Booster Engine Cutoff
The RD-180 engine is commanded to cut off once minimum residual propellant is sensed inside the Atlas booster stage.
T+03:05	Atlas/Centaur Separation
Six seconds after engine shutdown, the Atlas booster stage separates from the Centaur upper stage. Over the next several seconds, the Centaur liquid hydrogen and liquid oxygen systems are readied for engine ignition and the nozzle extension is deployed.
T+03:16	Centaur Engine Start
MES 1, the longer of the two Centaur firings, begins to inject the upper stage and the classified NRO spacecraft into an initial parking orbit around Earth.
T+03:24	Jettison Payload Fairing
The 14-foot diameter aluminum payload fairing that protected the classified NRO spacecraft during launch is separated once heating levels drop to predetermined limits.
T+17:23	Centaur Engine Cutoff
MECO 1 occurs when the single Centaur engine is shut down, with the rocket arriving in a planned parking orbit. The vehicle begins a coast period in its highly inclined orbit before arriving at the required location in space for the second burn.
T+74:35	Centaur Engine Re-start
MES 2 occurs over the South Pacific Ocean. The burn accelerates the vehicle and payload into the required deployment orbit.
T+74:58	Centaur Engine Cutoff
At the point of MECO 2, the Centaur and NRO spacecraft should be in the targeted orbit, completing the powered phase of the launch. The stage then begins aligning to the satellite separation attitude.
T+78:33	Spacecraft Separation
The classified National Reconnaissance Office spacecraft is released into orbit from the Centaur upper stage to complete the AC-206 launch, the final flight for Lockheed Martin's Atlas 3 rocket.

Data source: International Launch Services.