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Atlas/SBIRS launch timeline
Posted: May 3, 2011

T-00:02.7 Engine Start
The Russian-designed RD-180 main engine is ignited and undergoes checkout prior to launch.
T+00:01.1 Liftoff
The United Launch Alliance Atlas 5 vehicle, designated AV-022, lifts off and begins a vertical rise away from Complex 41 at Cape Canaveral Air Force Station, Florida.
T+01:30.6 Mach 1 and Max Q
The Atlas rocket achieves Mach 1 some 81 seconds into the flight, then passes through the region of maximum dynamic pressure at 91 seconds.
T+04:03.0 Main Engine Cutoff
The RD-180 main engine completes its firing after consuming its kerosene and liquid oxygen fuel supply in the Atlas first stage.
T+04:09.0 Stage Separation
The Common Core Booster first stage of the Atlas 5 rocket separates from the Centaur upper stage. Over the next few seconds, the Centaur engine liquid hydrogen and liquid oxygen systems are readied for ignition.
T+04:19.0 Centaur Ignition 1
The Centaur RL10 engine ignites for the longer of the two upper stage firings. This burn will inject the Centaur stage and SBIRS GEO 1 spacecraft into a parking orbit.
T+04:27.0 Nose Cone Jettison
The two-piece payload fairing that protected the SBIRS GEO 1 craft during the atmospheric ascent is separated to reveal the satellite to space.
T+15:31.9 Centaur Cutoff 1
The Centaur engine shuts down after arriving in a planned parking orbit. The vehicle enters a brief coast period lasting nearly 9 minutes before arriving at the required location in space for the second burn.
T+24:17.0 Centaur Ignition 2
The Centaur re-ignites over the equatorial Atlantic to accelerate the payload into geosynchronous transfer orbit from the parking achieved earlier in the launch sequence.
T+28:09.5 Centaur Cutoff 2
At the conclusion of its second firing, the Centaur will have delivered the SBIRS GEO 1 spacecraft into the targeted orbit with an apogee of 22,236 statute miles, perigee of 115 statute miles and inclination of 21.64 degrees.
T+43:19.5 Spacecraft Separation
The U.S. military's first Space Based Infrared System Geosynchronous spacecraft, or SBIRS GEO-1, is released into orbit from the Centaur upper stage to complete the AV-022 launch.

Data source: United Launch Alliance.