







Falcon 9 countdown timeline

SPACEFLIGHT NOW

Posted: June 19, 2014



NOTE: All times approximate T-minus 13 hours, 30 minutes Power Vehicle Launch controllers power up the Falcon 9 rocket for countdown operations. T-minus 3 hours, 50 minutes Begin LOX Loading Liquid oxygen begins flowing into the Falcon 9 rocket's first and second stages. T-minus 3 hours, 40 minutes Begin RP-1 Loading Highly-refined kerosene - a product called RP-1 - begins flowing into the Falcon 9 rocket's first and second stages. T-minus 3 hours, 15 minutes Fueling Complete The Falcon 9's propellant tanks are full. Cryogenic liquid oxygen will continue to be replenished until the final minutes of the countdown. T-minus 13 minutes Final Readiness Poll The launch team is polled for their "go" or "no go" for entering the terminal countdown. T-minus 10 minutes Terminal Countdown Autosequence Start The computer-controlled terminal countdown automatic sequence begins at T-minus 10 minutes. T-minus 9 minutes Begin Merlin Engine Chilldown Pre-valves open to allow super-cold liquid oxygen to flow into the Falcon 9's nine first stage Merlin 1D engines to condition the engine turbopumps for ignition. T-minus 6 minutes Align Flight Computer/Internal Power The Falcon 9's flight computer is aligned for flight, and the rocket is transitioned to internal power supplies. T-minus 3 minutes Terminate LOX Loading/FTS Internal Power The liquid oxygen replenishment to the rocket's first and second stages ends and the system is readied for liftoff. And the rocket's flight termination system is switched to internal power. T-minus 2 minutes SpaceX Reports GO The SpaceX launch director confirms the Falcon 9 is "go" for launch. T-minus 2 minutes Air Force Range Reports GO The U.S. Air Force range safety officer verifies "go" for launch. T-minus 1 minute Flight Computer in Start-Up Mode The Falcon 9 flight computer is commanded to start-up mode, and the launch pad's Niagara and deck water systems are activated. T-minus 50 seconds First Stage Steering Check The thrust vector control, or gimbal, system on the first stage's Merlin 1D engines is checked for launch. T-minus 40 seconds Pressurize Propellant Tanks The Falcon 9's first and second stage propellant tanks are pressurized for flight. T-minus 3 seconds Start Engine Ignition Sequence The engine controller commands the Falcon 9's nine Merlin 1D first stage engines to ignite, followed by a computer health check to verify the engines are healthy before liftoff.

Data source: SpaceX

