T-00:02.4	Engine start
	Atlas booster and sustainer engines are ignited and undergo checkout prior to liftoff.
T+00:00	Launch
	The Atlas 2A rocket, designated AC-143, lifts off and begins a vertical rise away from launch pad 36A at Cape Canaveral Air Force Station, Florida.
T+00:08	Roll Program
	During vertical ascent, Atlas begins a 7-second roll maneuver to align itself with proper flight azimuth. Following the roll, the Centaur inertial guidance system controls pitch and yaw programs.
T+02:45	Booster Engine Cutoff
	BECO occurs when axial acceleration of 5.0 g is obtained. Sustainer engine provides the continued boost toward orbit for the Atlas rocket.
T+02:48	Jettison Booster Package
	The bottom engine structure with the two booster engine nozzles is separated from the Atlas vehicle.
T+03:38	Jettison Payload Fairing
	The 14-foot diameter aluminum payload fairing that protected the TDRS-I satellite during launch through the atmosphere is separated once heating levels drop to predetermined limits.
T+04:35	Sustainer Engine Cutoff
	SECO is commanded once minimum residual propellant is sensed inside the Atlas booster stage.
T+04:37	Atlas/Centaur Separation
	The Atlas booster stage separates from the Centaur upper stage. Over the next few seconds, the Centaur engine nozzles are deployed and liquid hydrogen and liquid oxygen systems are readied for ignition.
T+04:53	Centaur 1st Main Engine Start
	MES 1, the longer of the two Centaur firings begins to inject the upper stage and TDRS-I spacecraft into a low-altitude parking orbit around Earth.
T+09:46	Centaur Main Engine Cutoff
	MECO 1 occurs the Centaur engines are shutdown, arriving in a planned parking orbit. The vehicle begins a coast period over the mid-Atlantic before arriving at the required location in space for the second burn.
T+24:29	Centaur Main Engine Re-start
	MES 2 occurs over the Atlantic Ocean between the African Ivory Coast and Ascension Island before the rocket passes over the equator. The burn lasts until all the Centaur fuel is used, placing TDRS-I into the highest energy transfer orbit possible.
T+25:50	Centaur Main Engine Cutoff
	At the point of MECO 2, the Centaur/TDRS-I vehicle should be in the required transfer orbit. Seconds later, the stage begins aligning to the satellite separation attitude.
T+29:37	Spacecraft Separation
	NASA's Tracking and Data Relay Satellite-I communications satellite is released into orbit from the Centaur upper stage to complete the AC-143 launch.

Image and data source: International Launch Services and Lockheed Martin Astronautics.