NASA and its launch partners are tracking several events during countdown and launch of Sentinel-6B aboard a SpaceX Falcon 9 rocket from Vandenberg Space Force Base in California.
Time | Events (all times are approximate): -00:43:00 | NASA launch manager propellant load and launch readiness poll-00:38:00 | SpaceX launch director verifies “go” for propellant load-00:35:00 | RP-1 (rocket grade kerosene) loading begins-00:35:00 | First stage liquid oxygen (LOX) loading begins-00:16:00 | Second stage LOX loading begins-00:07:00 | Falcon 9 begins engine chill prior to launch-00:04:00 | NASA “go/no-go” poll for launch-00:01:00 | Command flight computer to begin final prelaunch checks-00:01:00 | Propellant tank pressurization to flight pressure begins-00:00:45 | SpaceX launch director verifies “go” for launch-00:00:03 | Engine controller commands engine ignition sequence to start00:00:00 | Falcon 9 liftoff00:01:12 | Max Q (moment of peak mechanical stress on the rocket)00:02:13 | First stage main engine cutoff (MECO)00:02:17 | First and second stages separate00:02:25 | Second stage engine starts (SES-1)00:02:30 | Falcon boostback burn start00:02:48 | Fairing deployment00:07:22 | First stage entry burn begin00:07:48 | First stage entry burn ends00:08:18 | Second stage engine cutoff (SECO-1)00:08:42 | First stage landing burn start00:09:11 | First st …