| T-00:02.4 |
Engine start |
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Atlas booster and sustainer engines are ignited and undergo checkout prior to liftoff. |
|
| T+00:00 |
Launch |
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The Atlas 2A rocket, designated AC-140, lifts off and begins a vertical rise away from launch pad 36A at Cape Canaveral Air Force Station, Florida. |
|
| T+00:02 |
Roll Program |
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During vertical ascent, Atlas begins a 13-second roll maneuver from its launch pad alignment of 104 degrees to the flight azimuth of 105 degrees. Following the roll, the Centaur inertial guidance system controls pitch and yaw programs. |
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| T+02:44 |
Booster Engine Cutoff |
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BECO occurs when axial acceleration of 5.5 g is obtained. Sustainer engine provides the continued boost toward orbit for the Atlas rocket. |
|
| T+02:47 |
Jettison Booster Package |
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The bottom engine structure with the two booster engines is separated from the Atlas vehicle as the sustainer engine remains firing. |
|
| T+03:52 |
Jettison Payload Fairing |
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The 11-foot diameter aluminum payload fairing that protected the DSCS B11 satellite during launch is separated once heating levels drop to predetermined limits. |
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| T+04:42 |
Sustainer Engine Cutoff |
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SECO is commanded once minimum residual propellant is sensed inside the Atlas booster stage. |
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| T+04:44 |
Atlas/Centaur Separation |
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The Atlas booster stage separates from the Centaur upper stage. Over the next few seconds, the Centaur liquid hydrogen and liquid oxygen systems are readied for engine ignition. |
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| T+05:01 |
Centaur 1st Main Engine Start |
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MES 1, the longer of the two Centaur firings begins to inject the upper stage and DSCS B11 spacecraft into a low-altitude parking orbit of 80 by 485 nautical miles around Earth. |
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| T+10:09 |
Centaur Main Engine Cutoff |
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MECO 1 occurs the Centaur engines are shutdown, arriving in a planned parking orbit with an inclination of 29.3 degrees. The vehicle begins a coast period over the mid-Atlantic before arriving at the required location in space for the second burn. |
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| T+22:18 |
Centaur 2nd Main Engine Start |
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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 DSCS B11 into the required subsynchronous transfer orbit. |
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| T+23:44 |
Centaur Main Engine Cutoff |
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At the point of MECO 2, the Centaur/DSCS B11 vehicle should be in the targeted transfer orbit. Shortly thereafter the stage begins aligning to the satellite separation attitude. |
|
| T+25:18 |
Start Spinup |
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The Centaur's reaction control system thrusters initiate the required spinup of the DSCS B11 satellite to 4.7 rpm. |
|
| T+26:39 |
Spacecraft Separation |
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The Defense Satellite Communications System B11 spacecraft is released into orbit from the Centaur upper stage to complete the AC-140 launch. |
