The internet started buzzing yesterday with the sound of rocket engines test firing. SpaceX successfully tested its Merlin 1D engine, bringing the company a step closer to its future rocket power. It's a landmark test for the company, but on the overall scale of space exploration we're still far from recapturing the power of the Saturn V's F-1 engines.
SpaceX's Merlin 1D, which uses kerosene and liquid oxygen as fuel, is the amped up version of its Merlin 1C engine. Clusters of nine 1C engines have sent the company's Falcon 9 rocket into orbit on three occasions, most recently for the historic mission to the International Space Station. Nine engines, the standard configuration for the Falcon 9's first stage, generate about 1.1 million pounds of thrust at launch.
The Merlin 1D engines is going to make the next generation of Falcon rockets a lot more powerful. Monday's 185 second test fire delivered 147,000 pounds of thrust. That's the full duration and power required during a Falcon 9 launch. Nine of these new engines clustered for the Falcon 9's first stage will give the rocket nearly 1.5 million pounds of thrust at launch. Applied to the Falcon Heavy, which uses 27 engines in its first stage, these upgraded Merlin engines will give the rocket an impressive 3.8 milion pounds of thrust at launch.
“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.”
But let's put this into historical perspective. Nine Merlin 1D engines provide the equivalent thrust of one F-1 engine meaning the Falcon Heavy is on track to provide a little over half the thrust of the Saturn V.
The Saturn V was powered by F-1 engines. Capable of generating 1.5 million pounds of thrust each, these engines also burned kerosene and liquid oxygen. NASA first worked the F-1 into the Nova design. Nova was the rocket designed to take men directly from the Earth to the Moon, a method called direct ascent, and between 1958 and 1962 it was the front runner of lunar capable rockets. Eight F-1 engines would give it 12 million pounds of thrust.
Engineers eventually determined that direct ascent was an inefficient way to get to the Moon, particularly when compared to methods that involve rendezvous. The method we're all familiar with today, lunar orbit rendezvous, was selected because it was the lightest mission to launch. With one craft landing on the moon instead of the whole assembly, the total spacecraft would be lighter and could go to the Moon using one Saturn class rocket. With this idea in the pipeline, Saturn took precedence over Nova in 1962.
Despite the change in rocket, the F-1 remained the central hardware. Five of these massive engines gave the Saturn V the 7.5 million pounds of thrust at launch necessary to send Apollo to the Moon.
Necessity was a key feature in the rocket’s design decision. The F-1 was the engine selected for the lunar missions not because it was available but because it would make the missions Wernher von Braun was dreaming up possible. If NASA wanted to send missions to the Moon and Mars, the state of technology at the time required engines as powerful as the F-1 to launch the hardware into Earth orbit and beyond.
Maybe Elon Musk's vision for SpaceX that doesn't need the awesome power of the F-1. The SpaceX founder and CEO has expressed his goals of getting men on Mars within 20 years. With this latest victory with the Merlin 1D engine, it looks like the company is still on track.