Saturn V

• 1. Introduction

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  Saturn V stands 363 feet tall, taller than the Statue of Liberty by a wide margin, and when its five F-1 engines fired together during a test at what is now the Stennis Space Center, the roar shattered the plate-glass window of a bank building in Picayune, Mississippi, 15 miles away. This was a machine so large and so loud it seemed to defy the assumption that anything built by human hands could work. Between 1967 and 1973, thirteen of these rockets launched from Kennedy Space Center, carrying 24 astronauts to the vicinity of the Moon. Not one of them was lost. How did a country go from wooden workshops in Texas to building the most capable heavy-lift rocket in history? Who built it, and why did it disappear so completely when it was done?

• 2. From Peenemunde to Huntsville

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  In September 1945, Wernher von Braun arrived in the United States under Operation Paperclip, a program authorized by President Truman that brought over 1,600 German rocket engineers and technicians from the former Nazi regime into American government employment. Von Braun had helped design the German V-2 rocket. His first American posting was Fort Strong, Massachusetts, then Fort Bliss, Texas, where conditions were starkly different from the well-funded facilities at Peenemunde. In 1950, von Braun told a reporter from The New Yorker, "At Peenemunde we had been coddled, here you were counting pennies." The team was given wooden workshops described as "primitive or aged" and could not leave the base without a military escort.

  All of that changed in 1957 when the Soviet Union launched Sputnik 1 atop an R-7 ICBM. American anxiety about a rocket that could carry a thermonuclear warhead to the United States accelerated every timeline. The Army turned to von Braun's group, who by then had produced the Jupiter series of rockets. The Juno I rocket, a direct descendant of that work, launched the first American satellite in January 1958. Von Braun called the Jupiter series "an infant Saturn," already thinking ahead to something much larger. He was joined in the Saturn program by fellow German transplants Kurt Debus and Arthur Rudolph, both of whom brought deep experience from the wartime rocket program to the American effort.

• 3. Building the Right Rocket

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  On the 25th of January 1962, NASA approved the design that would become the Saturn V. The three-stage rocket was designated C-5 before receiving its final name in February 1963. The same month, a broader naming convention was confirmed: the C-1 became the Saturn I and the C-1B became Saturn IB. NASA administrator James E. Webb formally announced on the 7th of November 1962, that the lunar orbit rendezvous method would be the mission architecture for Apollo. That decision had enormous consequences for which rocket would be needed.

  The debate over how to reach the Moon had occupied engineers for years. Direct ascent would have required an enormous rocket, and NASA had proposed a vehicle called the Nova for that purpose. Earth orbit rendezvous would split the spacecraft into two pieces launched separately. Langley Research Center engineer John Houbolt spent much of 1961 campaigning for lunar orbit rendezvous, which required only a single rocket launching a mother ship and a small two-man lander. His persistence caught the attention of James Chamberlin, the engineer overseeing what would become Project Gemini, and eventually convinced George Low at NASA. Von Braun himself announced at a June 1962 meeting that lunar orbit rendezvous would be MSFC's preference. That choice made the Saturn V the right size for the job.

  The rocket's design philosophy called for "all-up" testing, meaning the very first flight would include complete, functioning versions of all three stages. This was a significant gamble, but it meant far fewer test flights would be needed before crewed launches. The program manager overseeing all of this was American George Mueller; the design work was concentrated at the Marshall Space Flight Center in Huntsville, Alabama, where von Braun led the technical effort.

• 4. Three Stages, Five Companies

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  Boeing built the S-IC first stage at the Michoud Assembly Facility in New Orleans and at the Mississippi Test Facility in Hancock County. The stage stood 42 meters tall and was powered by five Rocketdyne F-1 engines arranged in a quincunx pattern, with the center engine fixed and the four outer engines hydraulically gimbaled for steering. The S-IC burned RP-1 kerosene with liquid oxygen and produced 7,500,000 pounds of force at sea level. Its burn time was approximately 150 seconds. The F-1 engines remain the most powerful single-chamber liquid-fuelled engines ever built.

  North American Aviation built the S-II second stage at Seal Beach, California. The S-II burned liquid hydrogen with liquid oxygen and produced 1,000,000 pounds of force in a vacuum across its five J-2 engines, burning for 395 seconds. When fully fueled, more than 90 percent of the stage's total mass was propellant. The second stage traveled to Florida aboard the USNS Point Barrow.

  Douglas Aircraft Company built the S-IVB third stage in Huntington Beach, California. It carried one J-2 engine and had two planned burn periods: 165 seconds for the first burn to reach Earth orbit, and 312 seconds for the trans-lunar injection burn. Its single engine produced 225,000 pounds of force. The S-IVB was unique in being designed for restart in space, and most of these stages were transported to Florida aboard the Aero Spacelines Super Guppy aircraft, an oversize cargo plane built specifically for large aerospace components.

  IBM and the Marshall Space Flight Center designed the Instrument Unit, a ring 260 inches in diameter and 36 inches tall that sat atop the S-IVB. It contained the guidance, navigation, and control systems. IBM assembled the unit at their Huntsville, Alabama facility. The Instrument Unit's Launch Vehicle Digital Computer calculated the most fuel-efficient trajectory to the target orbit in real time during S-II flight, switching from a pre-programmed path to iterative guidance at around 3 minutes and 24 seconds after launch.

• 5. The Harrowing Test Campaign

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  Before a single Saturn V flew with humans aboard, the development program endured a string of accidents that tested the project's structural limits. The second stage's development was especially troubled. In the spring of 1965, NASA canceled production of the intended test article, the S-II-D, and substituted the S-II-S stage, which had been completed by North American Aviation's Space and Information Systems Division at Seal Beach. That stage was designated S-II-S/D for dual use. On the 29th of September 1965, it ruptured and was destroyed during a test at Seal Beach when engineers discovered it had been exercised to approximately 144 percent of its designed load limit.

  NASA then switched to the S-II-T stage. On the 28th of May 1966, while that stage was undergoing a pressure test to locate a hydrogen leak, hydrogen pressure sensors and switches had been disconnected without the knowledge of the second-shift crew. Believing a valve was leaking liquid hydrogen, the crew began closing valves. The liquid hydrogen tank over-pressurized and exploded, injuring five men and hospitalizing two.

  With the S-II-T/D destroyed, engineers turned to the S-II-F stage, a non-flight article from Kennedy Space Center. It arrived at Marshall Space Flight Center on the 10th of November 1966. By the end of November, the full test stack was assembled, and Configuration One testing finished on March 11. On the 3rd of August 1967, MSFC announced that the dynamic test program was complete and the Saturn V was ready for its first launch. The first uncrewed test flight, Apollo 4, launched on the 9th of November 1967, at 12:00:01 UTC.

• 6. Flying to the Moon

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  Apollo 8 in December 1968 became the first crewed flight to leave low Earth orbit, carrying its crew to lunar orbit and back. The standard mission profile that followed was built around the rocket's enormous performance envelope. The five F-1 engines burned for roughly two and a half minutes before first-stage separation, dropping the spent booster on a ballistic arc into the Atlantic Ocean about 350 miles downrange. The second stage fired for nearly seven minutes before separating at an altitude of about 101 nautical miles at a speed exceeding 22,000 feet per second. The S-IVB then burned to establish a parking orbit about 100 nautical miles above Earth, with the spacecraft orbiting one and a half times before the engine restarted for the trans-lunar injection burn, giving the craft a velocity of about 35,567 feet per second.

  Not every flight was routine. Apollo 12, which launched the 14th of November 1969, was struck twice by lightning shortly after liftoff but did not suffer serious damage and completed the second crewed lunar landing near Surveyor 3 at the Ocean of Storms. Apollo 13 in April 1970 suffered severe pogo oscillations in the second stage that forced an early center engine shutdown; the guidance system compensated by burning the remaining engines longer. The lunar landing was aborted when the service module failed. Apollo 15 was the first extended mission, carrying a Lunar Roving Vehicle and a Scientific Instrument Module in the service module bay. Apollo 17, which launched on the 7th of December 1972, was the only night launch in the program and made the sixth and final crewed lunar landing at Taurus-Littrow.

  The last Saturn V to fly carried the Skylab orbital workshop, launching on the 14th of May 1973. For that mission, the station replaced the S-IVB third stage, converted from a Saturn V component into the laboratory itself. The S-II second stage used on that flight remained in orbit for close to two years before making an uncontrolled re-entry on the 11th of January 1975.

• 7. What Was Never Built

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  From 1964 through 1973, NASA appropriated $6.417 billion for the Saturn V's research, development, and flights. The peak year was 1966, when Saturn V funding alone reached $1.2 billion, the same year NASA received its largest total budget: $4.5 billion, about 0.5 percent of U.S. gross domestic product. By the early 1970s, with public attention shifting to the Vietnam War and improved U.S.-Soviet relations reducing political pressure, Congress cut NASA's budget sharply. Two Saturn Vs that had been designated for Apollo 19 and Apollo 20 were never launched. A third unused vehicle, originally a Skylab backup, is now displayed in three separate locations: its first stage at the Infinity Science Center in Mississippi, its second stage at Johnson Space Center, and its third stage at the National Air and Space Museum.

  The canceled second production run would likely have carried an uprated F-1 engine in the first stage, plus bigger fins, a stretched S-IC stage, and a more powerful HG-3 engine for the upper stages. Proposed variants ranged from the Saturn INT-20 to the Saturn V-24(L), which would have mounted five uprated F-1 engines plus four strap-on boosters carrying two uprated F-1 engines each, for thirteen engines firing at launch. NASA also studied a crewed Venus flyby mission using the Saturn V and a nuclear upper stage called NERVA, as well as the Prospector, a 330-kilogram robotic lunar rover.

  Edgar Cortright, who had been the director of NASA Langley, recalled years later that he had been the leading proponent for using the Saturn V on post-Apollo missions and acknowledged losing that argument. A variant called the Saturn-Shuttle, which might have replaced the Space Shuttle's solid rocket boosters, was also never realized. The solid rocket boosters that were used instead ultimately contributed to the Challenger accident in 1986.

• 8. What Survived

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  On the 3rd of September 2002, astronomer Bill Yeung discovered what appeared to be a small asteroid in orbit around Earth, designated J002E3. Spectral analysis revealed the object was coated in white titanium dioxide, the same paint used on the Saturn V. Orbital calculations pointed to the Apollo 12 S-IVB stage. Mission planners had intended to send that stage into solar orbit after separation, but it is believed the engine burn ran too long, leaving the stage in a barely stable orbit around the Earth and Moon. In 1971, through a series of gravitational perturbations, it apparently drifted into a solar orbit, then returned to weakly captured Earth orbit 31 years later. It left again in June 2003.

  Three Saturn Vs survive on the ground in various configurations. The one at the U.S. Space and Rocket Center in Huntsville consists of the original dynamic test stages, displayed outdoors from 1969 to 2007 before being restored and moved inside the Davidson Center for Space Exploration. The display at Johnson Space Center is the only one assembled entirely from stages that were intended to actually fly. The Kennedy Space Center Visitor Complex enclosed its display in 1996 in the Apollo/Saturn V Center. The Saturn V holds the record for the largest payload to low Earth orbit, at 140,000 kilograms, a figure that stood unchallenged until the Space Launch System flew decades later.