EDITOR’S NOTE: Updated for new launch attempt on Jan. 19.
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 4 satellite for U.S. military infrared reconnaissance. Launch is scheduled for Friday at 7:48 p.m. EST (0048 GMT Saturday).
The Atlas 5 has a 40-minute window for takeoff Friday night, and the 189-foot-tall rocket will arc to the east from Florida’s Space Coast on its first flight of the year. It will be the 75th Atlas 5 launch overall since United Launch Alliance’s workhorse rocket debuted in August 2002.
The timeline below ends with the conclusion of the primary mission, the deployment of the SBIRS GEO Flight 4 satellite into geostationary transfer orbit. The Centaur’s RL10 engine will ignite a third time at T+plus 1 hour, 14 minutes, 17 seconds, for a planned 10-second de-orbit burn to steer the rocket back into Earth’s atmosphere, ensuring it does not add to space debris in orbit.
The Centaur is expected to re-enter over the Pacific Ocean, with most of it burning up in the atmosphere around 9 hours, 25 minutes, after liftoff.
Follow live coverage of the countdown and launch in our Mission Status Center.
T+04:09.3 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.
T+13:49.9 Centaur Cutoff 1
The Centaur engine shuts down after arriving in a planned low-Earth parking orbit. The vehicle enters a 10-minute coast period before arriving at the required location in space for the second burn.
See earlier SBIRS GEO Flight 4 coverage.