An upgraded Merlin engine designed to boost the lift capacity of SpaceX's Falcon 9 rocket has completed a full mission duration test firing in Texas, the company announced Monday.

The Merlin 1D engine completed 185-second firing with 147,000 pounds of thrust, SpaceX announced.

Credit: SpaceX

Future Falcon 9 rockets will be powered by nine Merlin 1D first stage engines. SpaceX calls the evolved booster the Falcon 9 v1.1.

The first flight of the Falcon 9 v1.1 launcher is expected in 2013 on SpaceX's first mission to lift off from Vandenberg Air Force Base, Calif. The primary payload for the launch is the Canadian Space Agency's Cassiope communications and research satellite.

The Falcon Heavy rocket, comprised of three Falcon 9 first stage cores, will use 27 Merlin 1D engines collectively generating 3.8 million pounds of thrust at liftoff.

"This is another important milestone in our efforts to push the boundaries of space technology," said Elon Musk, SpaceX's CEO and chief designer. "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."

SpaceX also said it completed multiple restarts of the Merlin 1D engine at its test facility in McGregor, Texas. A modified version of the engine for vacuum firings will be used on Falcon 9 upper stages.

"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," SpaceX said in a statement.

The company says the engine is also tailored for high rates of production utilizing fewer parts and robotic construction methods.