Hello, and good afternoon from NASA’s Kennedy Space Center in Florida! A SpaceX Falcon 9 rocket and Dragon spacecraft stand ready for liftoff at Kennedy’s Launch Complex 39A. Today’s launch is targeted for 1:29 p.m. EDT, just a little under 30 minutes away, and live countdown coverage has begun. Watch now on NASA TV or the agency’s website.
The second flight for SpaceX under NASA’s second Commercial Resupply Services Contract, and the company’s 22nd overall cargo resupply mission, this mission will deliver more than 7,300 pounds of science experiments and research, crew supplies, and hardware to the International Space Station.
Here’s a look at some of today’s countdown and ascent milestones. All times are approximate:
COUNTDOWN
Hr/Min/Sec Event
– 00:38:00 SpaceX Launch Director verifies go for propellant load
– 00:35:00 RP-1 (rocket grade kerosene) loading begins
– 00:35:00 1st stage LOX (liquid oxygen) loading begins
– 00:16:00 2nd stage LOX loading begins
– 00:07:00 Falcon 9 begins pre-launch engine chill
– 00:05:00 Dragon transitions to internal power
– 00:01:00 Command flight computer to begin final prelaunch checks
– 00:01:00 Propellant tanks pressurize for flight
– 00:00:45 SpaceX Launch Director verifies go for launch
– 00:00:03 Engine controller commands engine ignition sequence to start
– 00:00:00 Falcon 9 liftoff
LAUNCH, LANDING, AND DRAGON DEPLOYMENT
Hr/Min/Sec Event
00:01:12 Max Q (moment of peak mechanical stress on the rocket)
00:02:26 1st stage main engine cutoff (MECO)
00:02:30 1st and 2nd stages separate
00:02:37 2nd stage engine starts
00:02:43 1st stage boostback burn begins
00:05:52 1st stage entry burn begins
00:07:41 1st stage landing
00:08:39 2nd stage engine cutoff (SECO)
00:11:52 Dragon separates from 2nd stage