A Look Ahead at Today’s Timeline

At NASA Kennedy Space Center’s Launch Complex 39A, the crew access arm has been extended to the SpaceX Crew Dragon spacecraft, attached atop the company's Falcon 9 rocket.
At NASA Kennedy Space Center’s Launch Complex 39A, the crew access arm has been extended to the SpaceX Crew Dragon spacecraft, attached atop the company’s Falcon 9 rocket. Liftoff of the Demo-1 mission to the International Space Station is scheduled for 2:49 a.m. EST. Image credit: NASA TV

In case you missed it, here’s a look at today’s planned timeline of countdown and ascent milestones:

Countdown and Liftoff
Min/Sec—Events
-45:00SpaceX Launch Director verifies “go” for propellant load
-37:00Dragon launch escape system is armed
-35:00RP-1 (rocket grade kerosene) loading begins
-35:00First stage LOX (liquid oxygen) loading begins
-16:00Second stage LOX loading begins
-07:00Falcon 9 begins engine chill prior to launch
-05:00Dragon transitions to internal power
-01:00Command flight computer to begin final prelaunch checks
-01:00Propellant tank pressurization to flight pressure begins
-00:45SpaceX Launch Director verifies go for launch
-00:03Engine controller commands engine ignition sequence to start
-00:00—Liftoff of the SpaceX Falcon 9 rocket and Crew Dragon spacecraft

Ascent, First Stage Landing and Dragon Deployment
Min/Sec—Events
00:58Max Q (moment of peak mechanical stress on the rocket)
02:35First stage main engine cutoff (MECO)
02:38First and second stages separate
02:42Second stage engine starts
07:48First stage entry burn
08:59Second stage engine cutoff (SECO-1)
09:24First stage landing burn
09:52First stage landing
11:00Dragon separates from second stage

SpaceX will attempt to land the Falcon 9 first stage on its autonomous drone ship, “Of Course I Still Love You,” which is waiting offshore in the Atlantic Ocean.