Spaceflight Now: Atlas launch report

AC-201 launch timeline
Posted: May 14, 2000

T-00:02.73 Engine Start
Engine start 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.
T+00:00 Launch
Liftoff 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.
T+00:02 Roll and Pitch Programs
Roll 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.
T+00:06 Throttle Up
Throttle up 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.
T+00:33 Throttle Down
Throttle down The RD-180 engine is throttled down to a thrust level of about 60 percent to ease the rocket through the dense lower atmosphere.
T+01:05 Through Max-Q
Transonic 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.
T+02:52 Throttle Down
Throttle down To prepare for the upcoming engine shutdown, the RD-180 is once again throttled down, this time to 47 percent.
T+03:02.1 Booster Engine Cutoff
BECO The RD-180 engine is commanded to cut off once minimum residual propellant is sensed inside the Atlas booster stage.
T+03:13.1 Atlas/Centaur Separation
Atlas separation 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.
T+03:31.5 Centaur 1st Main Engine Start
MES-1 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.
T+03:39.5 Jettison Payload Fairing
Fairing separation The 14-foot diameter aluminum payload fairing that protected the W4 satellite during launch is separated once heating levels drop to predetermined limits.
T+12:15.6 Centaur Main Engine Cutoff
MECO-1 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.
T+22:39.8 Centaur 2nd Main Engine Start
MES-2 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.
T+26:15.4 Centaur Main Engine Cutoff
MECO-2 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.
T+28:53.4 Spacecraft Separation
Spacecraft separation 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.

Image and data source: International Launch Services and Lockheed Martin Astronautics.
Flight data file
Vehicle: Atlas 3A (AC-201)
Payload: Eutelsat's W4
Launch date: May 24, 2000
Launch window: 2139-2358 GMT (5:39-7:58 p.m. EDT)
Launch site: SLC-36B, Cape Canaveral, Fla.

Pre-launch briefing
Launch preview - Read our story for a complete preview of the first Atlas 3A launch.

Atlas 3A vehicle data - Overview of the rocket that will launch W4 into space.

The RD-180 - Facts and figures about the Russian-built engine to power Atlas 3.

Eutelsat W4 - Description of the satellite to be launched on AC-201.

Launch windows - Available windows for future launch dates of AC-201.

Video vault
Watch the planned sequence of events as the inaugural Atlas 3A rocket carries the Eutelsat W4 telecommunications satellite into orbit.
  PLAY (775k, 2min 39sec QuickTime file)
Learn about the engines and stages of the Lockheed Martin Atlas 3A rocket that will launch the Eutelsat W4 satellite.
  PLAY (342k, 49sec QuickTime file)
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