AC-142 launch timeline
Posted: July 20, 2001

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 The Atlas 2A rocket, designated AC-142, lifts off and begins a vertical rise away from launch pad 36A at Cape Canaveral Air Force Station, Florida.
T+00:02 Roll Program
Roll During vertical ascent, Atlas begins a 13-second roll maneuver from its launch pad alignment to the flight azimuth of 106 degrees. Following the roll, the Centaur inertial guidance system controls pitch and yaw programs.
T+02:44 Booster Engine Cutoff
BECO 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
Booster sep The bottom engine structure with the two booster engine nozzles is separated from the Atlas vehicle as the sustainer engine remains firing.
T+03:39 Jettison Payload Fairing
Fairing separation The 14-foot diameter aluminum payload fairing that protected the GOES-M satellite during launch is separated once heating levels drop to predetermined limits.
T+04:41 Sustainer Engine Cutoff
SECO SECO is commanded once minimum residual propellant is sensed inside the Atlas booster stage.
T+04:44 Atlas/Centaur Separation
Atlas separation 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 Centaur 1st Main Engine Start
MES-1 MES 1, the longer of the two Centaur firings begins to inject the upper stage and GOES-M spacecraft into a low-altitude parking orbit around Earth.
T+09:40 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+22:02 Centaur 2nd 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 places GOES-M into the required super-synchronous transfer orbit.
T+23:33 Centaur Main Engine Cutoff
MECO-2 At the point of MECO 2, the Centaur/GOES-M vehicle should be in the targeted transfer orbit with an apogee of 22,845 nautical miles, perigee of 149 nm and inclination of 20.54 deg. Shortly thereafter the stage begins aligning to the satellite separation attitude.
T+27:00 Spacecraft Separation
Spacecraft separation The Geostationary Operational Environmental Satellite-M weather spacecraft is released into orbit from the Centaur upper stage to complete the AC-142 launch.

Image and data source: International Launch Services and Lockheed Martin Astronautics.
Flight data file
Vehicle: Atlas 2A (AC-142)
Payload: GOES-M
Launch date: July 22, 2001
Launch window: 3:01-4:25 a.m. EDT (0701-0825 GMT)
Launch site: SLC-36A, Cape Canaveral, Fla.

Pre-launch briefing
Ground track - See the trajectory the rocket will follow during its flight.

Atlas 2A vehicle data - Overview of the rocket to be used in this launch.

GOES-M - Description of the weather satellite and its role in forecasting.

Launch windows - Listing of the available times to launch in coming days.

Atlas index - A directory of our previous Atlas launch coverage.