SpaceX has completed a Launch Readiness Test (LRT) including a Wet Dress Rehearsal (WDR) that loaded liquid oxygen and RP-1 kerosene into the two stage Falcon 9 rocket and ran the countdown through to T-5 seconds.
The countdown began at T-minus two hours and thirty-five minutes. Key events included lowering the strongback erector at the 100 minute mark, on second stage fuel and thrust vector control bleeding at T-1 hour, a final flight readiness poll at T-minus 13 minutes, and the final hold point at T-11 minutes.
Following these events, the terminal count began, which saw the transfer to internal power at T-4:46, arming of the flight termination system at T-3:11, oxidizer topping complete at T-3:04 and start of the flight computer at T-60 seconds.
An unknown issue stopped the count for 60 seconds at T-0. The SpaceX team recycled back to T-10 minutes, proceeded through the pressurization tasks at T-40 seconds and concluded the WDR at T-5 seconds.
The Falcon 9 was loaded with 39,000 gallons of liquid oxygen and 25,000 gallons of kerosene in the first stage, and 7,300 gallons of liquid oxygen and 4,600 gallons of kerosene in the second stage. Thursday’s count down tested the ground systems and support teams. The nine Merlin engines on the first stage will have a brief test firing before the actual launch, which is scheduled for late April. This will be the combined Demo 2 and 3 (D2/D3 or C2/C3), under the Commercial Orbital Transportation Services (COTS) contract. SpaceX has a $1.6 billion contract to resupply the space station with 12 missions.