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Atlas/GPS 2F-4 launch timeline
Posted: May 3, 2013

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-039, lifts off and begins a vertical rise away from Complex 41 at Cape Canaveral Air Force Station, Florida.
T+01:18.4 Mach 1 and Max Q
The Atlas rocket achieves Mach 1 some 78 seconds into the flight, then passes through the region of maximum dynamic pressure at 91 seconds.
T+04:04.4 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+04:10.4 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+04:20.4 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 GPS 2F-4 spacecraft into a transfer orbit.
T+04:28.4 Nose Cone Jettison
The two-piece payload fairing that protected the GPS 2F-4 craft during the atmospheric ascent is separated to reveal the satellite to space.
T+17:07.1 Centaur Cutoff 1
The Centaur engine shuts down after arriving in a planned elliptical transfer orbit. The vehicle enters a three-hour coast period before arriving at the required location in space for the second burn.
T+3:17:37:8 Centaur Ignition 2
The Centaur re-ignites to circularize the orbit and enter the GPS satellite constellation.
T+3:19:07.1 Centaur Cutoff 2
At the conclusion of its second firing, the Centaur will have delivered the GPS spacecraft into the targeted circular orbit of 11,047 nautical miles, inclined 55 degrees to the equator.
T+3:23:52.8 Spacecraft Separation
The Global Positioning System 2F-4 navigation satellite is released into orbit from the Centaur upper stage to complete the AV-039 launch.

Data source: United Launch Alliance.