On Sunday, September 29, 2013, SpaceX successfully completed the demonstration mission of its upgraded Falcon 9 rocket, delivering the CASSIOPE, CUSat, DANDE and POPACS satellites to their targeted orbits. All of the satellite owners are in contact with their spacecraft and are reporting nominal operations.
This was the first Falcon 9 launch using SpaceX's new 17 foot diameter fairing, designed and built in house by SpaceX. The fairing separates using pneumatic pushers instead of explosives and is large enough to fit a city bus. This was also the first launch from SpaceX's newly refurbished launch pad at Vandenberg Air Force Base, and the first demonstration of a number of technologies on the upgraded vehicle.
On this mission, Falcon 9 lifted off with nine Merlin 1D engines, generating 1.3 million pounds of thrust at liftoff and increasing to 1.5 million pounds of thrust as it approached the vacuum of space—nearly twice the thrust than when previously powered by the Merlin 1C. The engines were configured in a more robust engine support structure called the Octaweb, which is easier to manufacture and improves the vehicles reliability. To fuel the more powerful engines, SpaceX extended the propellant tanks by approximately 60%. The upgraded vehicle featured a triple-redundant avionics system similar to that used on Dragon, providing a single-fault tolerant architecture. A new stage separation system reduced the number of connection points from 12 to 3, and the vehicle also flew with a stronger heat shield that allows the rocket to reenter Earth's atmosphere and eventually land propulsively.
The flight proceeded according to plan, with a nominal first-stage flight and shutdown 2 minutes and 41 seconds after launch. Stage separation occurred at 2 minutes and 45 seconds, with MVac ignition following 7 seconds later. SpaceX's new fairing separated at approximately 3 minutes 32 seconds into launch. Nine minutes and 2 seconds into flight, the upper stage engine shut down. Approximately 14 minutes into flight, CASSIOPE was deployed directly at its target orbit of 325x1500km, 81 deg inclination. Each system performed as expected and all payloads were delivered to their intended destinations.
Following separation of the last payload, SpaceX attempted an internal milestone of relighting the second stage. Conditions appeared satisfactory for relight of the upper stage engine as the stage flew over Antarctica. The engine initiated ignition, with pressure rising in the thrust chamber to about 400 psi, but the flight computer sensed conditions did not meet criteria and it aborted the ignition. SpaceX believes it understands the issue which didn't involve anything fundamental, rather a need to iron out some of the differences between operating the engine on the ground versus in a vacuum. SpaceX has actually relit the Merlin engine in ground testing a dozen times in some cases and SpaceX is confident it can make the necessary adjustments before the next flight.
Despite reports to the contrary, the Falcon 9 second stage remained intact and healthy following spacecraft separation. It takes a few days to get the data from the Air Force Satellite Control Network into the SpaceX data system for review, but the data confirms the stage passed over Hawaii from approximately 1748 to 1754 Universal Time (10:48-10:54 PDT), roughly 1 hr 48 minutes after launch, starting into our second orbit. SpaceX still had power on the second stage, and the transmitters were left on to drain the batteries (standard procedure).
Though not a primary mission objective, SpaceX was also able to initiate two engine relights on the first stage. For the first restart burn, we lit three engines to do a supersonic retro propulsion, which we believe may be the first attempt by any rocket stage. The first restart burn was completed well and enabled the stage to survive reentering the atmosphere in a controlled fashion.
SpaceX then lit the center engine for a single engine burn. That relight also went well, however we exceeded the roll control authority of the attitude control thrusters. This particular stage was not equipped with landing gear which could have helped stabilize the stage like fins would on an aircraft. The stage ended up spinning to a degree that was greater than we could control with the gas thrusters on board and ultimately we hit the water relatively hard.
However, SpaceX recovered portions of the stage and now, along with the Grasshopper tests, we believe we have all the pieces to achieve a full recovery of the boost stage.
This launch also marked the first of three certification flights needed to certify Falcon 9 to fly missions for the U.S. Air Force under the Evolved Expendable Launch Vehicle (EELV) program. When Falcon 9 is certified, SpaceX will be eligible to compete for all National Security Space (NSS) missions.
The next few months remain busy for SpaceX and the upgraded Falcon 9. We are currently preparing to launch our first geosynchronous transfer orbit mission out of Cape Canaveral with SES-8 followed by Thaicom and our next trip to the space station in the early part of next year.
posted 08-29-2013 07:44 PM
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