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"SpaceX has added another string to its now weighty bow by successfully test firing the Merlin 1D engine, which will propel future craft into the thermosphere. The 1D is the sequel to the Merlin engines used to convey the DragonX to the International Space Station, with an improved thrust-to-weight ratio that reportedly makes it the most efficient booster engine ever built. It's hoped that the gear will be ready to make the jump to full use in time for the sixth flight of the Falcon 9, currently pencilled in for 2013. If you're the sort who enjoys watching a big pile of fire being pushed into a concrete chamber, you're really gonna love the video after the break.Show full PR text      SPACEX'S MERLIN 1D ENGINE ACHIEVES FULL MISSION DURATION FIRING     Hawthorne, CA &amp;ndash; Space Exploration Technologies (SpaceX) announces that its Merlin 1D engine has achieved a full mission duration firing and multiple restarts at target thrust and specific impulse (Isp).     The engine firing was for 185 seconds with 147,000 pounds of thrust, the full duration and power required for a Falcon 9 rocket launch. The tests took place at SpaceX's rocket development facility in McGregor, Texas.     \"This is another important milestone in our efforts to push the boundaries of space technology,\" said SpaceX CEO and Chief Designer Elon Musk. \"With the Merlin 1D powering the Falcon 9 and Falcon Heavy rockets, SpaceX will be capable of carrying a full range of payloads to orbit.\"     The Merlin 1D builds on the proven technology of the Merlin engines used on the first three flights of Falcon 9, including the recent historic mission to the International Space Station.     With nine Merlins on the first stage, the Falcon 9 rocket will produce nearly 1.5 million pounds of thrust in a vacuum. An enhanced design makes the Merlin 1D the most efficient booster engine ever built, with a vacuum thrust-to-weight ratio exceeding 150, while still maintaining the structural and thermal safety margins needed to carry astronauts.     Additionally, as SpaceX continues to fulfill an extensive manifest of launches, the new engine is designed for improved manufacturability by using higher efficiency processes, increased robotic construction and reduced parts count.     The Merlin 1D engines will first see flight on Falcon 9 Flight 6, expected to launch in 2013."^^<http://www.w3.org/2001/XMLSchema#string>
<http://www.engadget.com/2012/06/26/spacex-merlin-1d-test-fire/>