T-00:02.73 |
Engine Start |
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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. |
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T+00:00 |
Launch |
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The maiden flight of Atlas 3A begins as the rocket is released from pad 36B at Cape Canaveral Air Force Station, Fla. A vertical rise away from pad begins. |
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T+00:02 |
Roll and Pitch Programs |
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During the vertical ascent Atlas completes a 7-second roll maneuver to align itself with proper flight azimuth. Following the roll, the rocket begins a pitch-over maneuver with Centaur inertial guidance system in control of pitch and yaw programs. |
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T+00:06 |
Throttle Up |
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The RD-180 engine is throttled up from its liftoff thrust of 74 percent to 92 percent after the rocket clears the launch pad 36B tower. |
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T+00:33 |
Throttle Down |
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The RD-180 engine is throttled down to a thrust level of about 60 percent to ease the rocket through the dense lower atmosphere. |
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T+01:05 |
Through Max-Q |
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The rocket passes through maximum dynamic pressure and goes transonic. The RD-180 now throttles back up to its cruise setting of just over 80 percent thrust, ramping up to 5.5 g's. |
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T+02:52 |
Throttle Down |
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To prepare for the upcoming engine shutdown, the RD-180 is once again throttled down, this time to 47 percent. |
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T+03:02.1 |
Booster Engine Cutoff |
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The RD-180 engine is commanded to cut off once minimum residual propellant is sensed inside the Atlas booster stage. |
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T+03:13.1 |
Atlas/Centaur Separation |
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Eleven seconds after engine shutdown, the Atlas booster stage separates from the Centaur upper stage. Over the next ten seconds, the Centaur liquid hydrogen and liquid oxygen systems are readied for engine ignition and the nozzle extension is positioned. |
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T+03:31.5 |
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 Eutelsat W4 communications satellite into a low altitude parking orbit around Earth. |
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T+03:39.5 |
Jettison Payload Fairing |
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The 14-foot diameter aluminum payload fairing that protected the W4 satellite during launch is separated once heating levels drop to predetermined limits. |
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T+12:15.6 |
Centaur Main Engine Cutoff |
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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 over the mid-Atlantic before arriving at the required location in space for the second burn. |
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T+22:39.8 |
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 just north of the equator. The burn accelerates the vehicle and satellite into the required supersynchronous transfer orbit. |
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T+26:15.4 |
Centaur Main Engine Cutoff |
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At the point of MECO 2, the Centaur/W4 vehicle should be in the required transfer orbit, completing the powered phase of the launch. About four seconds later, the stage begins aligning to the satellite separation attitude. |
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T+28:53.4 |
Spacecraft Separation |
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The W4 communications satellite for Eutelsat is released into orbit from the Centaur upper stage to complete the AC-201 launch -- the maiden flight of Lockheed Martin's Atlas 3A rocket. |