This is the launch timeline to be followed by the Atlas 5 rocket’s ascent into orbit from Cape Canaveral with the SBIRS GEO Flight 3 satellite for U.S. military infrared reconnaissance. Launch is scheduled for Thursday at 7:46 p.m. EST (0046 GMT).
With the RD-180 main engine running, the Atlas 5 vehicle lifts off and begins a vertical rise away from Complex 41 at Cape Canaveral Air Force Station, Florida.
T+00:90.6: Max Q
The Atlas rocket, after breaking the sound barrier at 81 seconds, passes through the region of maximum dynamic pressure during ascent through the lower atmosphere.
T+04:03.2 Main Engine Cutoff
The RD-180 main engine completes its firing after consuming its kerosene and liquid oxygen fuel supply in the Atlas first stage.
T+04:09.2 Stage Separation
The Common Core Booster first stage of the Atlas 5 rocket separates from the Centaur upper stage. Over the next few seconds, the Centaur engine liquid hydrogen and liquid oxygen systems are readied for ignition.
+04:19.2 Centaur Ignition 1
The Centaur RL10C-1 engine ignites for the first of two upper stage firings. This burn will inject the Centaur stage and SBIRS spacecraft into an initial parking orbit.
T+04:27.2 Nose Cone Jettison
The payload fairing that protected the SBIRS GEO Flight 3 spacecraft during launch is separated after passage through the atmosphere.
T+15:22.9 Centaur Cutoff 1
The Centaur engine shuts down after arriving in a planned low-Earth parking orbit. The vehicle enters a 9-minute coast period before arriving at the required location in space for the second burn.
T+25:00.1 Centaur Ignition 2
A final push by Centaur is ignited to raise the orbit’s low point and reduce orbital inclination for the SBIRS GEO Flight 3 spacecraft.
T+28:38.3 Centaur Cutoff 2
The powered phase of flight is concluded as the Centaur reaches the planned geosynchronous transfer orbit of 115 by 22,237 statute miles and inclined at 23.29 degrees.
T+43:48.3 Spacecraft Separation
The SBIRS GEO Flight 3 missile warning sentinel is released into orbit from the Centaur upper stage to complete the launch.
See earlier SBIRS GEO Flight 3 coverage.
Our Atlas archive.