Spaceflight Now: Atlas launch report

AC-137 launch timeline
Posted: May 1, 2000

T-00:02.4 Engine start
Engine start Atlas booster and sustainer engines are ignited and undergo checkout prior to liftoff.
T+00:00 Launch
Liftoff Rocket lifts off and begins a vertical rise away from launch pad 36A at Cape Canaveral Air Force Station, Fla.
T+00:02 Roll Program
Roll During vertical ascent, Atlas begins a 13-second roll maneuver to align itself with proper flight azimuth. Following the roll, the Centaur inertial guidance system controls pitch and yaw programs.
T+02:44.1 Booster Engine Cutoff
BECO BECO occurs when axial acceleration of 5.0 g is obtained. Sustainer engine provides the continued boost toward orbit for the Atlas rocket.
T+02:47.2 Jettison Booster Package
Booster sep The bottom engine structure with the two booster engines is separated from the Atlas vehicle.
T+03:40.9 Jettison Payload Fairing
Fairing separation The 14-foot diameter aluminum payload fairing that protected the GOES-L satellite during launch is separated once heating levels drop to predetermined limits.
T+04:41.7 Sustainer Engine Cutoff
SECO SECO is commanded once minimum residual propellant is sensed inside the Atlas booster stage.
T+04:43.6 Atlas/Centaur Separation
Atlas separation Two seconds after the Atlas sustainer engine shuts down, 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.
T+05:00.2 Centaur 1st Main Engine Start
MES-1 MES 1, the longer of the two Centaur firings begins to inject the upper stage and GOES-L spacecraft into a slightly eccentric parking orbit around Earth.
T+09:38.9 Centaur Main Engine Cutoff
Coast 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+22:04.3 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 over the equator. The burn accelerates the vehicle and satellite into the required supersynchronous transfer orbit.
T+23:35.6 Centaur Main Engine Cutoff
MECO-2 At the point of MECO 2, the Centaur/GOES-L vehicle should be in the required transfer orbit. About four seconds later, the stage begins aligning to the satellite separation attitude.
T+25:20.6 Start Spinup
Spinup The Centaur's reaction control system thrusters initiate the required spinup of the GOES-L satellite to 7.0 degrees per second.
T+27:02.6 Spacecraft Separation
Spacecraft separation The GOES-L weather satellite is released into orbit from the Centaur upper stage to complete the AC-137 launch.

Image and data source: International Launch Services and Lockheed Martin Astronautics.
Flight data file
Vehicle: Atlas 2A (AC-137)
Payload: GOES-L
Launch date: May 3, 2000
Launch window: 0627-0953 GMT (2:27-5:53 a.m. EDT)
Launch site: SLC-36A, Cape Canaveral Air Force Station, Fla.

Pre-launch briefing
Launch preview - Read our story for a complete preview of the GOES-L launch.

Atlas 2A vehicle data - Overview of the rocket that will launch GOES-L into space.

GOES-L - Description of the satellite to be launched on AC-137.

Launch windows - Available windows for future launch dates of AC-137.

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