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NIST Helps Restore a Blast (Off) from the Past

More than four decades after it was last used, the Saturn V rocket—the vehicle that carried the U.S. Apollo astronauts to the moon and back between 1968 and 1972—still holds the title of the most powerful liquid-fueled propulsion system ever created.

Apollo 11 lifting off
Five F-1 engines provided a total liftoff thrust of 3.4 million kilograms (7.5 million pounds) for the historic Apollo 11 moon landing mission on July 16, 1969.
Credit: NASA

The five F-1 engines of the Saturn V’s first stage, known as the S-1C, each packed a staggering 700,000 kilograms (1.5 million pounds) of thrust at liftoff. That’s equivalent to 24 million kilowatts (32 million horsepower) of power or the output of 100,000 sports cars.

After the S-1C stage completed its mission to get the Saturn V to 67 kilometers (42 miles) high in less than 2-1/2 minutes—by achieving speeds greater than Mach 7 (8,600 kilometers per hour or 5,300 miles per hour)—it was unceremoniously dropped into an Atlantic Ocean grave some 4,300 meters (14,000 feet) below the surface.

The Saturn V F-1 engine sitting on the ocean floor
The thrust chamber of a Saturn V F-1 engine on the ocean floor, as seen where it sat for more than 40 years.
Credit: Bezos Expeditions

That is, until 2013, when billionaire entrepreneur and founder Jeff Bezos led an expedition that recovered 11,300 kilograms (25,000 pounds) of components from the F-1 engines that launched the Apollo 11, 12 and 16 lunar landing missions in July 1969, November 1969 and April 1972, respectively. Included were five thrust chambers, one exhaust nozzle, two heat exchangers, four turbines, three turbine manifolds and one gas generator, all of which were taken to the Kansas Cosmosphere and Space Center in Hutchinson, Kansas, for processing.

Preserving the thrust chambers and exhaust nozzle posed a special problem for conservators because they were constructed of a nickel-based superalloy called Inconel X-750 that was designed to withstand temperatures up to 3,300 degrees Celsius (6,000 degrees Fahrenheit). Unfortunately, no one had ever studied the reaction of this material to decades of seawater exposure, so the conservation team did not know how best to treat the artifacts made from it.

National Institute of Standards and Technology (NIST) engineers Tim Foecke and Adam Creuziger were enlisted to help the Kansas Cosmosphere staff identify the corrosion mechanisms that they would be dealing with during conservation of the Iconel X-750 components. The NIST researchers developed a complex sample stabilization technique and examined samples from the corroded artifacts under scanning electron microscopy and X-ray microanalysis. They discovered that the structure of the superalloy was altered by the very thing it was designed to withstand—the incredibly high heat of the F-1 engine exhaust. The Iconel X-750 that started out composed of microscopic cube-shaped elements transformed into a substance made up of tiny branch-like structures called dendrites. Foecke and Creuziger also found that the change made Iconel X-750 easier to stabilize (remove corrosive salts left behind by exposure to seawater) than in its original state, a welcomed bonus for the conservators.

Today, the recovered F-1 engine parts may be seen at the Kansas Cosmosphere; the Smithsonian National Air and Space Museum in Washington, D.C.; the Museum of Flight in Seattle; and the Kent, Washington, headquarters of Blue Origin, the Bezos company developing commercial space vehicles.

Photo of the recovered F-1 engine components that are on display at the Museum of Flight
Recovered F-1 engine components on display at the Museum of Flight.
Credit: Museum of Flight, Seattle

Wernher von Braun standing next to the (very large) F-1 engines.
Rocket pioneer Wernher von Braun standing next to the F-1 engines in the first stage of the Saturn V booster he helped create.
Credit: NASA
Did You Know...?

  • The Saturn V S-1C first stage stood 42 meters (138 feet) tall and had a diameter of 10 meters (33 feet). Its height was nearly two-fifths of the total 110 meters (363 feet) for the combined Saturn V booster and Apollo spacecraft. The S-1C was powered by 1.2 million liters (318,000 gallons) of liquid oxygen and 770,000 liters (203,000 gallons) of RP-1, a kerosene-based fuel.
  • The combined roar of the S-1C’s five F-1 engines at launch produced about 220 decibels (human eardrums rupture at 195 decibels), which was dampened by dumping 3.4 million liters (900,000 gallons) of water a minute below the rocket. 
  • Although never built, NASA plans in the late 1950s included a booster larger and more powerful than the Saturn V known as Nova. Its first stage would marshal the thrust of eight F-1 engines, three more than the S-1C stage of the Saturn V. Nova was intended for a direct flight to the moon and was abandoned when the Earth orbit to lunar trajectory mission strategy was chosen for Project Apollo.

    – Michael E. Newman

    Created June 20, 2017, Updated February 13, 2019