Saturn V, the birth of the lunar rocket

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. .

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.

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 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

. 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 assigned 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

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.

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.

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.

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.

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

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. .

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.

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.

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.

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.

As its name indicates, the Earth Orbit Rendezvous mission is to assemble 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

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 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

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 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.

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.

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 disassembled 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.

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.

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.

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.

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 mass 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.

. 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.

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.

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.

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 ramasser 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 assez profonds pour élever des bancs massifs 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 assez effrayés pour se relocaliser.

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 assurance 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.

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.

Even assembling 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 assemble 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.

When the various bits arrived at the VAB, they were inspected before final assembly 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.

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.

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.

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.

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 passed 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