Nov 15 2007
Space Exploration Technologies Corp. (SpaceX) announced today that it has completed development of its Merlin 1C next generation liquid fueled rocket booster engine. It is among the highest performing gas generator cycle kerosene engines ever built, exceeding the Boeing Delta II main engine, the Lockheed Atlas II main engine, and on par with the Saturn V F-1 engine.
The Merlin 1C is an improved version of the Merlin 1A ablatively cooled engine, which lofted the Falcon 1 on its first flight in March 2006 and second flight in March 2007. The regeneratively cooled Merlin 1C uses rocket propellant grade kerosene (RP-1), a refined form of jet fuel, to first cool the combustion chamber and nozzle before being combined with the liquid oxygen to create thrust. This cooling allows for higher performance without significantly increasing engine mass.
“We performed the final test in the development series, a 170 second long mission duty firing,” said Tom Mueller, Vice President of Propulsion for SpaceX, from their Texas Test Facility in McGregor, Texas. “This series of runs has verified the final design features. Total run time on this engine exceeded 3,000 seconds across 125 hot fire tests.”
“The SpaceX Texas test facility was critical to the rapid and efficient development of Merlin,” said Elon Musk, CEO and CTO of SpaceX. “In August alone, we ran twenty-one major Merlin test firings, nearly one per working day, a rate we could not equal anywhere else. The success of Merlin is really due to the joint function of a great propulsion and test team.”
Merlin 1C in its Falcon 9 first stage configuration has a thrust at sea level of 95,000 lbs, a vacuum thrust of over 108,000 pounds, vacuum specific impulse of 304 seconds and sea level thrust to weight ratio of 92. In generating this thrust, Merlin consumes 350 lbs/second of propellant and the chamber and nozzle, cooled by 100 lbs/sec of kerosene, are capable of absorbing 10 MW of heat energy. A planned turbopump upgrade in 2009 will improve the thrust by over 20% and the thrust to weight ratio by approximately 25%.
The Merlin 1C will power SpaceX’s next Falcon 1 mission, scheduled to lift off in early 2008 from the SpaceX launch complex in the Central Pacific atoll of Kwajalein. SpaceX’s far larger Falcon 9 rocket, now in development, will employ nine Merlin engines on its first stage, and one on the second stage. The Falcon 9 will have over a million pounds of thrust – four times the maximum thrust of a Boeing 747.
The Merlin engine is the first new American booster engine in ten years and only the second in over a quarter century. The prior two American engines were the RS-68 developed in the late nineties by Pratt & Whitney’s RocketDyne division, used in the Boeing Delta IV launch vehicle, and the Space Shuttle Main Engine developed in the late seventies, also by RocketDyne.
SpaceX is preparing to produce more rocket engines than the rest of US production combined. In 2008, SpaceX targets the manufacture of approximately 50 booster engines, a number that exceeds the output of any country except Russia.