Falcon 9 makes thundering night Launch from Florida, delivers two Satellites
March 2, 2015
This early rollout was required to allow the two satellite payloads sufficient time to complete final battery charging and reconfigurations for countdown operations. Over the course of the day on Sunday, technicians were busy at the launch pad, hooking Falcon 9 up to umbilical, purge, pressurant, power and data lines.
Launch Vehicle power-up was planned at L-10 hours to mark the start of testing conducted on the various subsystems of the launch vehicle. Over the course of the initial hours of the countdown, Falcon 9 went through electrical testing, flight computer checks, propulsion system verifications, communication checks and Flight Termination System Testing.
Following tank chilldown, LOX started flowing into Falcon 9 two hours and 35 minutes ahead of the opening of the launch window.
The first stage of the rocket is filled with propellant components and other commodities via the launch mount at the base of the rocket while the second stage was loaded with consumables via interfaces on the Strongback structure. All in all, the first stage of Falcon 9 received about 385,000 Kilograms of propellants while the second stage was loaded with 90,000kg of LOX and RP-1. During tanking, Falcon 9 was filled with Nitrogen Attitude Control System Propellant and Helium pressurant gas for use in propellant tank pressurization during the flight on both stages. Overall, the Falcon 9 stands 68.4 meters tall with a launch mass of around 505 metric tons.
Being initiated ten minutes ahead of launch, the highly choreographed Automated Countdown Sequence included the final computer-controlled steps to transition Falcon 9 to its liftoff configuration.
As the master countdown script started running, teams made sure the sequencer had picked up. Range recorders were activated, launch enable was switched to flight and the ground-based TEA-TEB ignition system of the engines was set up for engine start. The nine Merlin 1D engines started chilldown at T-9:30 to condition their turbopumps for ignition, Pre-valves were opened and temperature data showed a good chilldown on all engines; trim valve cycling on the engines was also performed.
Loading of LOX, Nitrogen and Helium into the two stages of Falcon 9 had closed out by T-90 seconds and GSE interfaces were purged. With one minute to go, the Flight Computers assumed control of all vehicle functions for the remainder of the countdown taking the first stage through a last Thrust Vector Control test at T-50 seconds and the pressurization of all tanks at T-40 seconds.
Within 20 seconds, all tanks were at full pressure and pyrotechnics were armed for launch. For sound suppression, the Niagara system started pouring thousands of liters of water onto the launch pad.
Heading past T+2 minutes, Falcon 9 was still on-course - beginning to throttle back its engines to limit acceleration on the launch vehicle as it got lighter and lighter as it approached cutoff. The MVac engine started its in-flight chilldown sequence while the first stage was still burning to condition its turbopump for ignition after separation of the second stage.
Two minutes and 56 seconds into the flight, the nine Merlin 1D engines had done their job and were shut down - not to be ignited again for any post-separation maneuvers. Just two seconds after MECO, the first stage was separated by mechanical collets and three pneumatic pushers that pushed the spent first stage away from the upper stage to pave the way for ignition of the second stage, starting out at an altitude of 90 Kilometers and a speed over Mach 10.
The second stage was expected to re-light its Merlin 1D engine at T+25 minutes and 42 seconds for a 59-second burn to boost the apogee of the orbit significantly and making a slight reduction in orbital inclination. The two payloads were targeting an insertion orbit will above the Geostationary Altitude of 35,800 Kilometers. According to SpaceX, the second stage re-start went without any problems and the vehicle arrived close to the expected orbit.