Spaceflight Now: Atlas launch report

AC-158 launch timeline
Posted: Feb. 2, 2000

T-00:02.4 Engine start
Engine start Atlas booster and sustainer engines are ignited and undergo checkout prior to liftoff. The two ground-start boosters will light a half-second before launch.
T+00:00 Launch
Liftoff Rocket lifts off and begins a vertical rise away from launch pad 36B at Cape Canaveral Air Station.
T+00:08 Roll Program
Roll During vertical ascent, Atlas begins a seven-second roll maneuver to align itself with proper flight azimuth. Following the roll, the Centaur inertial guidance system controls pitch and yaw programs.
T+00:59.1 Air-lit SRB Ignition
Air-lit The remaining two solid rocket boosters strapped to the Atlas are ignited once onboard computer software determines the two ground-start SRBs have burned out, about 2 1/2 seconds earlier.
T+01:06.8 Jettison Ground-Lit SRBs
Ground-lit sep The two spent solid rocket boosters that were ignited on the ground are jettisoned to fall into the Atlantic Ocean.
T+01:57.1 Jettison Air-Lit SRBs
Air-let sep Computer software will determine the air-start solid rocket boosters have burned all their propellant and should be jettisoned from the Atlas vehicle. The two SRBs will fall into the Atlantic Ocean.
T+02:43.9 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+02:47.0 Jettison Booster Package
Booster sep The bottom engine structure with the two booster engines is separated from the Atlas vehicle.
T+03:21.4 Jettison Payload Fairing
Fairing separation The 14-foot diameter aluminum payload fairing that protected the Hispasat 1C satellite during launch is separated once heating levels drop to predetermined limits.
T+05:00.7 Sustainer Engine Cutoff
SECO SECO is commanded once minimum residual propellant is sensed inside the Atlas booster stage.
T+05:02.7 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 and engine nozzles extended.
T+05:19.2 Centaur 1st Main Engine Start
MES-1 MES 1, the longer of the two Centaur firings begins to inject the upper stage and Hispasat 1C spacecraft into a low-altitude parking orbit around Earth. Guidance steering in the burn will result in an inclination of 27.3 degrees.
T+09:44.3 Centaur Main Engine Cutoff
Coast MECO 1 occurs the Centaur engines are shutdown, arriving in a planned 81.6 x 201.5 nautical mile orbit. The vehicle begins a coast period over the mid-Atlantic before arriving at the required location in space for the second burn.
T+24:30.5 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+26:18.2 Centaur Main Engine Cutoff
MECO-2 At the point of MECO 2, the Centaur/Hispasat 1C vehicle should be in the required transfer orbit. About four seconds later, the stage begins aligning to the satellite separation attitude.
T+25:17.4 Start Spinup
Spinup The Centaur's reaction control system thrusters initiate the required spinup of the Hispasat 1C satellite to 1.5 rpm.
T+28:56.2 Spacecraft Separation
Spacecraft separation The Spanish Hispasat 1C communications satellite is released into orbit from the Centaur upper stage to complete the AC-158 launch.

Image and data source: International Launch Services and Lockheed Martin Astronautics.
Flight data file
Vehicle: Atlas 2AS (AC-158)
Payload: Hispasat 1C
Launch date: Feb. 3, 2000
Launch window: 2310-0002 GMT (6:10-7:02 p.m. EST)
Launch site: SLC-36B, Cape Canaveral Air Station, Fla.

Video vault
An in-depth look at the Lockheed Martin Atlas 2AS rocket and Centaur upper stage that will launch Hispasat 1C.
  PLAY (431k, 1min 02sec QuickTime file)

Pre-launch briefing
Atlas 2AS vehicle data - Overview of the rocket that will launch Hispasat 1C into space.

Hispasat 1C - Description of the satellite to be launched on AC-158.

Launch windows - Available windows for future launch dates of AC-158.

Atlas index - Listing of our previous Atlas coverage.

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