Saturn V, the birth of the lunar rocket



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On July 16, 1969 at 9:31 AM EDT, the Florida landscape around the Kennedy Space Center shook as the Apollo 11 mission took off from its historic mission of taking the first astronauts to the moon. The rocket the size of a skyscraper that made this possible is probably the most recognizable machine of the 20th century, but the construction of the Saturn V was not so simple. His birth is a brilliant technical innovation story tinged with engineering conservatism, politics, fighting and having to work on a project that no one had more than a blurry design up to ##################################################################################### In a surprisingly late era

If you've ever visited one of the Saturn V survivors on display at the Kennedy Space Center in Florida or the Johnson Space Center in Texas, you can understand that the lunar rocket is a magnet for the superlatives. Not only was it the key technology for the biggest event since a fish decided to try to leave the ocean, but it 's accumulating an amazing collection of records that hold to this day. .

The Saturn V is the tallest rocket, standing taller than the Statue of Liberty or Big Ben, at a height of 110.6 m (363 ft). It is also the heaviest rocket, weighing 2,970,000 kg (6,540,000 lb) and the most powerful rocket ever put into service. With an initial thrust of 7 891 000 lb (35 101 kN), it could project a payload of 310 000 lb (140 000 kg) in low Earth orbit and 107 100 lb (48 600 kg) on ​​a trajectory to the moon.

T enough, this is not only the largest liquid fuel rocket, but the largest flying machine ever built. Its F-1 first-stage engine is the most powerful to put into operation. The construction of the 13 Saturn Vs and their 19 younger siblings Saturn I and Saturn IB involved 20,000 private companies and more than 300,000 people across the Americas. In addition, it is considered by NASA as the first true space vehicle and is still the only one to send astronauts in deep space.

And there is more. On 32 Saturn launches, not one failed and no payloads were lost. Considering that NASA's engineers and astronauts were always amazed every time we lifted them up instead of exploding on the carpet, it's an incredible record.

Born of chaos

But what is really remarkable about the Saturn V, is the story that animates it. For such a revolutionary machine, its birth was both short and appallingly complicated. Designed from 1960 to 1962 at Marshall Space Flight Center of NASA (formerly ABMA) in Huntsville, Alabama under the direction of rocket pioneer Wernher von Braun and Arthur Rudolph, the first Saturn V flew in November 1967 Five years after getting the green light for the Apollo mission

That would be pretty impressive, but behind all this, a story of incredible complication involving a bewildering number of parallel developments, complex decision-making, intense political battles. , international crises and push the boundaries of science and engineering to their limits. Saturn V was at the center of a convergence of events, including interservice rivalries, the Cold War, the race to space, departmental competition, the birth of new agencies, and the entire project is tossed around like a hot potato – and while trying to forge an unprecedented partnership between government and private enterprise.

Just to make things interesting, it is also the story of a rocket that no one was really sure of. to do with or how to do it, once the decision is made

The first glow

The history of Saturn V begins during the Second World War when Nazi Germany has deployed its ballistic missile V -2. Developed at Peenemunde, the V-2 was the largest liquid fuel rocket ever built and its design had so much influence on subsequent work that the Saturn V can, in many ways, be considered a Super V-2

. The last days of the war, Wernher von Braun and 700 of the best German scientists went to the US Army. They, along with plan trucks and hundreds of V-2 rockets, were secretly shipped to the United States as part of the Paperclip operation. Von Braun had chosen to surrender to the Americans because he thought the United States had the freedom and resources to allow him to pursue his goal of building a lunar rocket, but the US government had other ideas

. Braun's ambitions, the Germans were confined to White Sands, New Mexico, where they were limited to playing with captured V-2s, teaching American engineers rocket science, and making short-range ballistic missiles for the army. In 1956, ABMA was founded and von Braun 's team perfected the design of the rockets, so advanced that they were badigned to a government supervisor whose role was to ensure that he was in charge. ensure that von Braun's team does not inadvertently place a satellite in orbit. Meanwhile, the US Air Force was developing a major official rocket program that developed ICBM missiles to carry nuclear weapons

Then, at the end of 1956, the US Department of Defense decided that He needed a rocket of large payloads vaguely specified in orbit. The main requirement was that the thruster should be able to lift loads ranging from 19,000 to 39,680 pounds (9,000 to 18,000 kg) and could be built quickly and at low cost. In April 1957, ABMA rose to the challenge and investigated the possibility of making a rocket called Super Jupiter that could develop a thrust of about 1.5 million lb (6.672 kN) – 10 times more powerful than No matter what rocket in the current Inventory

Originally, the idea of ​​the von Braun team was to use a huge engine, but it was decided by following use four smaller but still gigantic engines that went into history under the name of F-1. Even if a single engine would have been lighter, simpler and would have been less prone to failure than a group of engines, development would take much longer. However, at this point, the Super Jupiter was little more than a concept and some calculations, which would probably never be built.

The turning point came when President Dwight Eisenhower announced that the United States would place an artificial satellite in orbit as part of the country's contribution to the International Geophysical Year of 1957. To underscore the peaceful nature of the launch The project, called Vanguard, was a civilian effort to improve a Navy rocket probe to make it fit to send a grapefruit-sized satellite into orbit.

good, but in October 1957 the Soviet Union launched the first satellite, Sputnik, into orbit. And for the point sticks, he sent a second and a third, as well as the first living creature in space, the dog Laika.

The result was official calm and public panic. The US government was not surprised by Sputnik and was even secretly relieved, as it meant that the Communists would have no reason to oppose US launches. But the press and the public in the free world went green because the USSR was considered relatively backward, and now it had fired a missile into space that could have just as easily carried a head nuclear power intended for New York or Washington.

What has worsened the fact is that Vanguard has gone from a quiet scientific enterprise to a national priority. He did not help things when the first attempt blew up the rocket on the block, presenting the Soviets with a mbadive propaganda victory and Americans with a loss of credibility.

Von Braun, on the other hand, had planned something like that and arranged several Jupiter missiles to be hidden for "storage tests". When Sputnik flew over me, von Braun said eagerly that he could set up a satellite in 90 days. When Vanguard's second attempt failed, ABMA already had a Jupiter, now called Juno-1, at Cape Canaveral, ready to send the first American satellite, Explorer I, into space, which he did. January 31, 1958.

NASA, ARPA and Saturn

The Sputnik incident galvanized the response of the United States and made space a top priority. In February 1958, the Advanced Research Projects Agency (ARPA, now DARPA) was founded to eliminate the entanglement of the bureaucracy and bureaucracy of the US government to advance science and technology projects. In April, Eisenhower authorized the creation of the National Aeronautics and Space Administration (NASA) to take over the civil space program.

In August 1958, the ABMA Super Jupiter effort – now called the Juno V – was boosted when ARPA committed money for the project. This was important because the army was losing interest in the giant rocket, was thinking about closing the project, and then, in 1960, handed it over to NASA without a penny to accompany it.

At that time, the name of the rocket was officially changed to Saturn, ABMA was dissolved and von Braun's team was transferred to Marshall Space Flight Center (MSFC) of NASA. In addition, even though Saturn was still largely a concept, engineers had a better idea of ​​the way forward

Which Saturn?

An example of the status of the Saturn project in 1960 was that there was not only one rocket, but at least five or six. At this point, Saturn was to be a family of multi-mission rockets in a number of configurations to handle different tasks and missions. Officially, there were five types designated C-1, C-2, C-3, C-4 and C-5, plus a super Nova rocket that would have overshadowed even the Saturn V if it had gone beyond the drawing board phase. .

The reason for so many rockets was that no one was very clear about what Saturn was supposed to do, or how they were supposed to do it. In addition, there was no clear path to develop them. If six different rockets seem a lot, keep in mind that these are just the main categories. At one point, there were so many variants of each of them that even the experts could not keep them straight. There were Saturns on one floor, two floors, three or four. Some had an engine, others had clusters. Some have been modified military rockets. Some were new. Some had webbing flares or solid boosters. It was the nightmare of a planner.

But the biggest problem was: what was the mission? To whom did the von Braun team design the Saturn, and why? At first, it was for the military community, but they quickly lost interest and preferred to go with their own program and threatened to cut funding. Then the control of von Braun's team and Saturn was transferred to NASA, but the nascent space agency had no idea what to do with a rocket giant, let alone what its final design should be.

in January 1960, when NASA told the US Congress that it could put a team into orbit around the moon in 10 years and an inhabited lander shortly thereafter. This deadline was not based on anything solid, but the agency found that a decade was on the right time for ambitious projects.

Then, as any connoisseur of the history of the Space Race knows, President Kennedy made his historic speech about the State of the Union on May 25, 1961. He dedicated the United States to the Moon saying: pledge to reach the goal, before the end of this decade, to send a man to the Moon and bring him back safely to Earth.

Kennedy's speech had all the drama necessary for a great historical mission. but what followed, as far as the moon was concerned, was seven months of scratches and disputes. Despite instructions from the president, NASA did not have its own rockets, and the military vehicles it relied on for the Mercury and Gemini projects were not up to the job.

As for Saturn, the multiple configurations were changing from month to month. The three-step versions have become two steps. C-I is transformed into C-I and C-IB. The Nova was favored at one point. Solid fuel boosters on another. In a nutshell, it was organized chaos. Let's hope that the moon program will change all that.

Go to the Moon

The main reason for all this change is that a major obstacle in the development of Saturn was that, as if to skin a cat, there is more than one way to reach the moon and each requires its own rocket. And in 1961, NASA faced four routes.

Direct Ascent

The first and most favored method is called Direct Ascent. The simplest of methods, the Direct Ascent scenario requires the construction of an autonomous spacecraft that a giant rocket would send into space. The craft would fly directly to the moon, then land on the surface without entering the lunar orbit. At the end of the mission, the entire spacecraft or an ascension stage took off, returned to Earth and landed or collapsed.

This is a perfectly healthy mission profile, but it suffers from a major disadvantage: the spacecraft is extremely heavy because of large engines, fuel tanks and other equipment including he needs. This meant a cargo ship weighing 90 tons (99 tons). The von Braun team calculated that it would require a radically new thruster called Nova, which pushed so much thrust that it would eclipse even the Saturn V and would need new monster engines. Worse still, this would have delayed the American landing until the 1970s.

Earth Orbit Rendezvous

As its name indicates, the Earth Orbit Rendezvous mission is to bademble the ship into orbit. After that, he would fly to the moon, land, and then come back. Alternatively, an unmounted ship would launch into orbit, and then fueled for travel by a second rocket. In any case, this would require smaller flares than the Saturn V.

This would have required two or more rocket launches followed by a rendezvous in Earth orbit, and then a docking or d & rsquo; A refueling. Such appointments are common in the 21st century, but in 1961, it was an unknown territory. Two spacecraft had never met in orbit, let alone accosted one to the other. In addition, the rockets at the time were still largely experimental and there was always the risk of a malfunction, which could result in the blockage of a spacecraft in orbit and nothing to meet it. This could mean the loss of two spacecraft for the price of a

Lunar Surface Rendezvous

In the Lunar Surface Rendezvous, a fleet of unmanned vessels would be sent to the moon with refueling, fuel and a ship capable of returning Earth. During the mission, a small inhabited lander would land and the astronauts would use the ship back to the surface to return. Again, the necessary rockets would be smaller.

The problem with the Lunar Surface Rendezvous is the same as the Orbital Earth Rendezvous, only worse. The Earth Rendezvous scenario only needed to place a few spacecraft on the same orbit at the same time. The lunar surface rendezvous would have required a landing on the moon using autonomous landing gear (which had never been done before), then repeating several times in the same place followed by an inhabited landing, then a takeoff in a second craft. Needless to say, it offered too many opportunities for incidents killing missions

Lunar Orbit Rendezvous

Lunar Orbit Rendezvous is a mission where a single spacecraft is sent into lunar orbit using a single launch vehicle . While the mothership stays in orbit, a small lander makes the descent, lands and then returns the astronauts using an even smaller ascension stage. The climb step meets the mothership, the astronauts return, the ascent stage is dropped, and the mothership returns to Earth

If this sounds familiar to you, then is because it was the Apollo program. was anything but easy. But the decision had to be made, and soon

Mission chosen

At first, the mission of Direct Ascent was preferred for its simplicity and the fact that it did not require the use of untested maneuvers like the orbital rendezvous. When the Nova rocket needed for such a mission proved unachievable, many members of the team (including von Braun) defended a terrestrial orbit while John Houbolt's engineer from Langley and the NASA administrator George Low were fighting for the lunar rendezvous.

The fighting became so severe that President Kennedy personally intervened at least once, and von Braun had to show great diplomatic skill to prevent winners and losers from engaging in personal hostility.

Finally, the lunar orbit rendezvous was chosen as the most profitable and the fastest to develop. As a result, the development of the Saturn could eventually move to the final design, followed by construction and testing. NASA announced on January 10, 1962 that production would begin on the Saturn C-5, now called Saturn V. It would include the first-stage S-IC with five F-1 boosters instead of the first four to provide a lot of extra power, a new second stage S-II powered by five J-2 engines, and the third stage S-IVB with a single J-2 engine. This third stage would carry the Apollo Command Service Module and Lunar Excursion Module, as well as the "brains" of the rocket.

With the Saturn V, two more rockets were allowed. Based on the Saturn C-1, the Saturn I and Saturn IB have been designed as parallel development rockets to test part of the Saturn V hardware, conduct preliminary flight tests, transport the Apollo spacecraft to orbit and send the first Apollo astronauts. These last two were particularly important because Apollo was to be fully developed by the time Saturn V. was put online.

The two stages Saturn I and IB illustrate the conservative nature of the Saturn program and the imperative of Save money on a Moon project that would cost soon as much as a little war. Much smaller than the Saturn V, their first stages were based on the first Juno and Redstone rockets and used five "demilitarized" H1 engines. To save on the cost of designing and building new fuel tanks, the eight Redstones tanks for carrying RP-1 fuel and liquid oxygen have been grouped around a Juno tank with more fuel. # 39; oxygen. The difference between the two configurations was that the IB was slightly larger, to carry more propellant.

The second stage of the rocket was S-IV or S-IVB. The S-IV used six RL-10 engines, which were replaced by a single J-2 engine in the S-IVB. The irony is that even though the S-IVB was the third floor of the Saturn V and was numbered IV, it was actually the first floor to fly, and was technologically the most advanced because it had to be able to fire twice and make complex course corrections.

Outstanding Issues

Beyond the basic decisions, others showed the state of the art rocket in the early 1960s. In the original rocket design Saturn, they had to only use RP-1, which is made from kerosene, and liquid oxygen. This would have made the Saturn V a very large and unsightly rocket that could have flown in flight. The alternative was to use liquid hydrogen on the upper floors, but von Braun opposed it on the pretext that Americans had little experience and that most of their knowledge came from the Germans. In addition, its properties were still poorly understood, and there was not much industry to manufacture it, so it was very expensive.

This changed thanks to Abraham Silverstein, who had worked with liquid hydrogen in the 1950s and was convinced of the aptitude. Eventually, he was able to talk around von Braun and other key scientists – especially in light of the fact that the Air Force was already working on a rocket called Centaur that was using hydrogen. In fact, the opinion of the development committee has evolved so much that hydrogen has been selected for the second and third stages.

Another decision to make was to know where to launch lunar missions. No current site was suitable, so it was necessary to choose somewhere where the appropriate facilities could be built. This would have huge consequences not only on how to build the Saturn V, but also on its basic design. Before Cape Canaveral was installed, there was concern that NASA would select a remote island in the Pacific Ocean, as the government has done for nuclear weapons testing, and l '. von Braun's team feared that the rocket would be disbadembled and transported by plane. By 1965, the basic design of the Saturn V and its smaller siblings had been largely settled as it progressed in production and testing. Although the design philosophy was to be conservative and to support as much as possible on the existing technology, the size of the rocket required many radical innovations.

To take one example, welding was a constant problem. Combining the metal smoothly while allowing it to undergo mbadive changes in stress and temperature is still a challenge in aeronautical engineering, but the Saturn V has introduced a whole new dimension. A weld in an exotic aluminum alloy could be relatively simple to make and inspect when it was only a few inches long, but when it must be a hundred feet long, it is everything else.

Then there were the engines. The F-1 was bigger than all the previous ones and the J-2 was one of the most advanced. Building and testing these introduces all kinds of difficulties. For example, a problem that continued to appear was called "instability of combustion". Or, to put it another way, the engine would develop horrible hiccups because the fuel and oxygen would refuse to mix properly, then burn spontaneously.

To deal with this need for frequent overhaul of the fuel injector and other components, as well as to find strange ways to simulate the effect by making tiny grenades that would be ready to explode in the combustion chamber. Things went so bad that engineers had to engage in very high levels of theoretical work, and von Braun suggested universities to encourage doctoral students to specialize in the problem.

Then there was the fact that the giant rocket was incredibly sensitive. It could have 35 floors, but the strict standards of the clean room had to be maintained at all times. Not only was there a danger that debris would end up in the weld or fuel line, but the oil from one footprint could cause a deadly explosion if it came in contact with the lube. liquid oxygen.

Despite these problems, the construction of the Saturn V was unrolled with remarkable speed – especially considering that it had to be constantly updated to include SI test results. and S-IB. Soon, it began to take shape in three major manufacturing sites across the United States.

This division of labor was necessary because NASA soon found that the work was well beyond its capacity. Instead, von Braun's team in Marshall undertakes the development and initial production, and then the actual construction of each stage is entrusted to a private contractor. This has sometimes worked well, as when Boeing worked on the SC-I, but also on his failures, as in North America, which did such a bad job building the S-II stage that NASA has had to reorganize mbadively.

The lower floor, the S-IC, was built by Boeing and measured 138 ft (42 m) high and had a diameter of 33 ft (10 m). Empty, it weighed only 130,000 kg (287,000 lbs), but when it was loaded with RP-1 and liquid oxygen, it weighed 2,040,000 lbs (2,290,000 kg). These fueled the five F-1 engines as they produced a thrust of 7,891,000 lbs (35,100 kN) for only 168 seconds, as they lifted and the rest of the rocket left the cushion and released it. Accelerated beyond the speed of sound.

Strangely, despite its large size and the spectacular roar of its ignition, it had the reputation of an "old man's tower" with little vibration and noise inside the capsule of the Crew that astronauts experienced during Gemini. Apollo astronauts even said that they did not know if they had taken off unless they checked the dashboard.

The second stage, S-II, was awarded to North American Aviation and was 24.8 m behind. high. With an empty weight of 40,400 kg and a power of 496,200 kg, it had five J-2 engines built by Rocketdyne that burned for 360 seconds. It was the most difficult of the three steps to build. Not only did it have problems as strange as composite tank liners that were only solved when the contractor hired surfboard experts, but he was having constant difficulties with project management and quality control. .

the S-IVB. Built by Douglas, it peaked at 61.6 ft (18.8 m) and had a diameter of 21.7 ft (6.6 m). It was also much lighter than the other stages with a mbad of only 123 000 kg (271 000 lb) fully powered. He had a single advanced J-2 engine that was unique to the Saturns in that he could fire twice – the first time for 165 seconds to place the third leg into orbit, and a second time for 335 seconds for the Send with his Apollo spacecraft payload to the moon.

Another unique feature of the S-IVB was the instrument unit that sat in a ring under the cone that housed the lunar module. Built by IBM in Huntsville, Alabama, it was the computer that controlled the entire rocket before take-off until the S-IVB was scrapped. This ring served as a structural base for the Apollo spacecraft and housed the environmental units, guidance system, gyroscopes, electronic cooling system and tracking system. This is what allowed the Saturn V to compare the acceleration and attitude of the rocket with respect to the programmed flight profile, and to make the appropriate corrections using engines that were tuned on gimbals that allowed them to pivot

. Le Saturn V et le module Apollo Command étaient montés sur le Launch Escape Tower. Cela comprenait un moteur-fusée solide qui, en cas d'abandon de mission, pouvait détacher le module de commande et l'éloigner de façon à pouvoir déployer ses parachutes

Ce dispositif d'évacuation fonctionnait avec le système de dispersion propulseur nommé par euphémisme. (PDS), qui a été conçu pour protéger le Centre spatial Kennedy et les communautés environnantes contre un Saturn V qui explose sur le pavé. En raison de l'énorme quantité de carburant et d'oxygène liquide à bord de la fusée, il avait la force explosive potentielle de deux kilotonnes de TNT ou la sortie d'une arme nucléaire tactique.

Puisqu'un Saturn V détonant aurait été l'une des plus grandes explosions non nucléaires de l'histoire de l'humanité, les trois étages du Saturn V étaient équipés d'explosifs que l'officier de sécurité de l'aire pouvait exploser en utilisant un signal radio. En cas d'urgence, un système de sécurité aurait maintenu les moteurs en marche pendant les 30 premières secondes de vol pour lui permettre de prendre de l'altitude. Un signal arrêterait alors les moteurs, et un second signal ouvrirait les réservoirs de telle sorte que le carburant et l'oxygène liquide se disperseraient pour les empêcher de se mélanger et de s'enflammer. Si aucune urgence ne se produisait, un troisième signal arrêterait définitivement les explosifs sur le troisième S-IVB quand il atteindrait l'orbite.

Un cauchemar logistique

Le Saturne V serait impressionnant à lui seul, mais derrière son histoire est un cauchemar logistique. La fusée n'existait pas seule, mais constituait l'aboutissement d'une énorme infrastructure avec des installations majeures en Alabama, en Louisiane, au Mississippi, au Kansas, dans l'État de Washington, en Californie, en Floride et ailleurs.

Bien que le V de Saturne ait été développé à Huntsville, il était bientôt trop grand pour l'installation même quand il était considérablement augmenté. De nouveaux sites étaient nécessaires, mais ils ne pouvaient être démontés n'importe où. Ils avaient besoin d'être loin des zones peuplées, pourtant près des voies de transport faciles. Étant donné que ceux-ci avaient tendance à être des voies navigables, les sites devaient être badez loin au sud pour que la glace ne soit pas un facteur.

Un site choisi était l'usine de montage de Michoud (MAF) à la Nouvelle-Orléans – une plantation de sucre qui a échoué et qui a été utilisée pour la fabrication durant la Seconde Guerre mondiale et la guerre de Corée. Adapter cela signifiait non seulement la construction de nouvelles usines et de bancs d'essais de fusées qui étaient les bâtiments les plus hauts de l'État, mais aussi le déplacement de centaines de familles d'une ville voisine avec des indemnisations très généreuses.

Les autres sites étaient le Mississippi Test Facility (MTF) à Bay St. Louis, Mississippi; l'installation informatique de Slidell à Slidell, en Louisiane; le site d'essai de moteur de fusée de la NASA à la base aérienne d'Edwards, en Californie; et des installations de production à Seal Beach, en Californie. Cela ne mentionne même pas les routes, les lignes de chemin de fer, les barges, les navires, les avions spéciaux, les chantiers navals et toutes sortes d'autres moyens de transport.

Ensuite, il y avait le contrôle de la mission à Houston, au Texas et le site de lancement. Cap Canaveral a été transformé d'une base de fusée en un véritable spatioport appelé Kennedy Space Center après l'badbadinat du président en 1963. Cela impliquait l'installation d'un site de contrôle de lancement, de centres de ravitaillement, de rampes de lancement géantes et l'érection du plus grand bâtiment du monde. le VAB (Vehicle Assembly Building) – c'est tellement grand que s'il n'y avait pas la climatisation, il pleuvrait à l'intérieur.

Même la nature devait être apprivoisée. Cap Canaveral avait des moustiques si épais qu'il était impossible de se déplacer sans un ensemble complet de vêtements, de gants et de masques, et un seul filet pouvait rambader les insectes à la fourrière sans problème. Pour les empêcher de torturer les travailleurs, les ingénieurs ont construit des barrages qui ont inondé les cours d'eau jusqu'à ce qu'ils soient badez profonds pour élever des bancs mbadifs de ménés pour manger les larves de moustiques

Si cela ne suffisait pas, les pigeons infesté les plus grands bâtiments et bombardé les machines de la lune avec des fientes. Après avoir tout essayé pour les abattre, les biologistes ont fini par donner aux pigeons une drogue qui les paralysait temporairement, ce qui les a badez effrayés pour se relocaliser.

Essais

Un facteur clé dans le succès de la Saturn V était les essais incessants effectués par la NASA. It's normal for an airplane to go through thousands of hours of flight tests before being declared airworthy, but that wasn't practical with the world's largest rocket, so the space agency built S-1 and S-1B for early flight tests and subjected every engine, component, system, and subsystem to endless ground tests. Combined with stringent reliability and quality badurance programs, this was cited as the reason for the Saturn V's safety record. In fact, testing made up half of the entire program.

The program was so effective that instead of testing the Saturn V stages individually, all three flew together in "all up" fashion on the first Apollo 4 mission. The success can be seen in that there was only one inflight problem before the manned flights when Apollo 6 experienced "pogoing" when the second stage fired. That is, one of the J-2 engines went unstable and started to vibrate in a way that could have destroyed the rocket. The engine shut down, but for some reason, a second one did as well, which placed the third stage in the wrong orbit.

The reasons behind this were surprisingly simple. The vibration was caused by a faulty design of a spark igniter on the faulty engine. This wasn't noticed in ground tests because the igniter would frost up from the cryogenic fuel, securing it in place, but in space there's no air, so no water vapor. With no icing, the igniter could shift, causing a faulty engine burn.

As to why the second engine shut down, that was due to cross wires that sent the signal to the wrong engine when the computer tried to correct. That was solved by making the offending wire too short to reach any engine but its own during installation.

Assembly

Even badembling the Saturn V required some major thinking and engineering. The usual way of putting a rocket together up until that time was to take the bits to the launch pad and bademble them there before fueling. That wasn't practical for a monster like Saturn V, especially in Florida, or when a high rate of launches are required, so a new way had to be found.

NASA opted for a new way to bademble the Saturn V far away from the launch pad in a protected area – the VAB, which could handle up to four Saturns at a time. But before that, the stages had to get to Florida by various routes. The S-IC had to be carried down by barge along the Mississippi River, then by sea through the Gulf of Mexico and into the Atlantic Ocean to Cape Canaveral. The S-II was built in California and went by ship through the Panama Cbad, while the S-IVB was airlifted in a bulbous cargo plane called the Super Guppy due to its resemblance to a pregnant tropical fish.

When the various bits arrived at the VAB, they were inspected before final badembly and then lifted into position on the Saturn V. The completed rocket was then set on the Crawler Transporter (CT) – a giant tractor that carried it the 3 miles (4.8 km) to Launch Complex 39. There, it was enveloped by the Mobile Service Structure (MSS), which included a portable clean room, lifts, fueling and power systems, and even a giant slide to evacuate the gantry crew to a special bunker in the event of a launch emergency.

Lift-off

After all this, it's surprising to learn that the career of each Saturn V that flew was only about 20 minutes, give or take some time parked in orbit. However, the lift-off of a Saturn did put any fireworks show on the planet to shame.

The first moments of a Saturn V launch were the most spectacular, but they were also the simplest and most dangerous. Due to the mbadive weight of the Saturn V, the first stage's flight was dominated by aerodynamic forces, so the S-IC didn't do much beyond keep the rocket stable during the first moments. Instead, it carried out a pre-programmed flight path and the onboard computers noticed any deviations, which the second and third stages would correct.

One of the most heart-stopping facts about the Saturn V was that it took a full 12 seconds to clear the launch tower. If it struck the tower or the engines cut out, the results would have been catastrophic, which is why the pad was three miles from anywhere. To reduce the chances of brushing the tower, the rocket was programmed to tilt 1.25⁰ away. When it reached an altitude of 430 ft (130 m), it rolled to its flight angle and gradually pitched down to a more horizontal position.

Two and a half minutes after launch, the Saturn V was hypersonic. The first stage, now spent of fuel, separated from the rest of the vehicle using explosive charges and solid rockets to push it away. Similar rockets on the second stage gave it a nudge to ensure that all the fuel was at the bottom of the tanks before the five J-2 engines ignited. The second stage burned for six minutes, boosting the velocity to 15,300 mph (24,623 km/h) before separating to crash into the Atlantic Ocean off the coast of West Africa.

Now the third stage came online. During its first burn, it boosted the remaining vehicle to 17,500 mph (28,164 km/h), then cut out as the spacecraft went into a parking orbit around the Earth. There it remained for up to three orbits while the crew and ground control checked out the systems before deciding to proceed. If the green light was given, the J-2 engine would fire for a second time, setting it and its payload in a translunar insertion orbit.

At this point, the Saturn V's job was done. The crew of the Apollo mission would dock with the Lunar Module, then make a course correction that would send it on its way to the Moon while the third stage arced safely out of the way to prevent a collision.

The end of an era

There's been nothing like the Saturn V since the heyday of the Space Race. The last one flew in 1973, when it lofted the Skylab space laboratory into orbit. All that remains of the booster's legacy are two flight-rated Saturn Vs on display in Texas and Florida, five S-IVBs that went into orbit around the Sun during Apollo 8 to 12, the remains for five more that were deliberately crashed on the Moon for seismic experiments during Apollo 13 to 17, and a few odds and ends scattered about in museums and warehouse.

But could we make a Saturn V today? According to NASA, no. Though all of the blueprints still survive on microfilm and the development and construction of the rocket has been carefully documented, the vast infrastructure and tools needed to build the giant rocket have all been destroyed, relegated to museums, or repurposed. In addition, the men and women behind the project are all either retired or have pbaded away.

Instead, it would be much simpler and cheaper to design and build a new rocket from scratch. That's why NASA is working on its

BFR, and even China is rumored to be working on a super rocket to rival the Saturn. No doubt one day a more powerful launcher will be produced, but the Saturn V will be so deeply embedded in history that it will still be the one that will set the standard against which all others will be compared.

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