The Saturn V launch, brought to you by five F-1 engines.
When the first Saturn V launched on November 9, 1967, the combined 7.5 million pounds of thrust from the five F-1 engines shook the CBS news building on live television. The F-1 remains the most powerful single chamber rocket engine ever built, a power NASA hopes to resurrect and apply to its Space Launch System (SLS). A team of engineers at NASA’s Marshall Spaceflight Centre in Huntsville, Alabama, are now dissecting the old engines to learn their secrets.
The first piece of the F-1 brought back to life with a hot fire test was the gas generator, a system of parts small enough to test in a lab that produce some explosive results. The gas generator is the part of an engine that supplies the power to drive the turbomachinery, which feeds propellant into the thrust chamber. For the F-1, the turbopump fed nearly three tons of propellant a second into the thrust chamber generating about 31,000 pounds of force. When all that propellant was thrust through engine’s nozzle it generated 1.5 million pounds of thrust.
A NASA test of the new gas generator.
The gas generator is a logical place to start – it’s a key part engineers use to determine the size of the finished engine. So knowing the details of this key piece of the F-1 is crucial to developing the next generation of engines. But testing pieces of a rocket that hasn’t fired in nearly 50 years isn’t easy. They aren’t exactly lying around shops in test condition, they’re in storage units and museums. So that’s where engineers went for F-1s.
One F-1 gas generator came from storage at Marshall, and another came from the Smithsonian National Air and Space Museum; the latter generator was in near pristine condition compared to the one in storage. Techs cleaned the half-century old parts with a technique called structured light 3D scanning, which produces 3D schematics to help keep the structure intact. They also used laser melting, a digital manufacturing technique that produces metal parts, to create new parts for tests.
An F-1 test fire in the 1960s. via
The goal is to capture the F-1’s power, but it won’t be a matter of just copying the hardware from one engine to another. The F-1 burned a mix of kerosene and liquid oxygen. The SLS, like the shuttle’s engines, will burn a more modern mix of liquid hydrogen and liquid oxygen. The two fuel mixtures aren't necessarily plug-and-play, so the study of the old design is also a study into rocket engineering.
There are more steps and more tests involved in the effort to bring the F-1 back to life to uncover its secrets. Eventually, Marshall engineers will use modern manufacturing techniques to build a new gas generator that will be measured against the F-1 test results. This is all in the name of getting big, powerful rockets launching from American soil sooner rather than later. The evolved configuration of the SLS is slated to carry payloads up to 130 metric tons (143-tons) Into orbit, so that rocket is going to need about the biggest engines it can find.
Of course, the real challenge in this reverse engineering the F-1 challenge is that no one really know how the Saturn V got its power. Pieces of the rocket were built by four main contractors and everything was assembled by NASA. When Apollo ended, a lot of the pieces and paperwork were strewn between sites and never compiled. So not only is building an engine based on the F-1’s power going to be really exciting, but historians might learn a little more about the giant lunar rocket. All told, this is a really awesome resurrection.