READY FOR LIFT OFF: SATURN V, THE ROCKET THAT PUT THE MAN ON THE MOON.

By Ian Gonzalez Lopez

One of the most known components of the Cold War between the USA and the USSR was the so called Space Race, which drove a thrilling technological innovation in both countries, started an ongoing launching of different spacecrafts and ultimately led to the first Moon landing. Along with the political line of these events, there is also a technical side marked with achievements and failures, and of course the main characters in this story are the rockets.

Images of different rocket models are now very popular, and videos of the countdown with the later lift off can easily been seen online. Maybe the most popular model of them is the Saturn V, and not without its reasons. This model is still the heaviest and tallest rocket nowadays, with a weight of almost 3,000 tons and a height of 110m, also is the one that has the highest total impulse. It is a multi-stage rocket, which means that for it to be correctly propelled it needs the activation of several stages that after they burn out their fuel, they are detached and then the next stage is activated.

The Saturn V rocket was developed fifty-one years ago and was used for many of the NASA’s Apollo missions, including the one that finally landed Neil Armstrong and Buzz Aldrin on the Moon. The historical importance of this rocket is tightly related to its success, since the arrival of the man at the Moon was a huge leap that marked the victory of the Space Race. Before the Saturn V rocket existed, there had been many others models of rockets made in the USA, but none of them was actually comparable to the most famous rocket.

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The final manned Saturn V, AS-512, before the launch of Apollo 17 in December 1972. Image Credit: NASA.

The main person behind the conception of the Saturn V rocket was Wernher von Braun, a scientist that was formerly part of the Nazi rocket development program, whom at the end of World War II was secretly brought to the USA to contribute with new rocket designs. This inclusion of ex-nazis scientists was not uncommon in any of the parties involved in the Cold War; while the USA had the Operation Paperclip program, the URSS had Operation “Osoaviakhim” (Operation Osoaviakhim was a Soviet operation which took place on 22 October 1946, with NKVD and Soviet army units forcibly recruiting more than 2,200 German specialists – a total of more than 6,000 people including family members – from the Soviet occupation zone of post-World War II Germany for employment in the Soviet Union) and both of them had the same objective: to gather the best rocket scientists in favor of their cause.

Just before Wernher made history with the Saturn V, the USSR launched Sputnik, a success that was seen by the press and popular opinion as a big blow to the USA in the Space Race. This event led to an acceleration of the rocket development and resulted in the Saturn V.

As one can imagine, not a single piece of the rocket design was left to randomness, instead, it was meticulously built. For example, the reason behind the usage of liquid fuel is because of its high density, which derives into needing less space for storage than other types of fuel. This is specially handy when one thinks of the amount of fuel needed to impulse a gigantic rocket like the Saturn V and its 3,000 t. weight.

As it is actually the heaviest of all full functioning rockets, getting the Saturn V into space requires a lot of impulse, which is given by a special propulsion mechanism composed by three different stages.

The first stage (named S-IC) was designed by Boeing, the famous aircraft building company. The S-IC is composed by five F-1 engines, which use RP-1 as fuel. The RP-1 is a form of refined petroleum known for its stability, and among other things is known by its high density. As stated before, this is a major advantage since it takes less volume to store more of it, making it ideal for the first stage. The stage is designed to evenly distribute the impulse provided by the five engines: four of them located at each corner and the other one at the center. The engines located at the corners can be rotated within their own axis to set a specific direction for the rocket.

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The Apollo 10 S-IC stage is hoisted in the vehicle assembly building for stacking. Image Credit: NASA

This first stages burns its fuel until the rocket is at about 67km high and later it is detached. After its detachment it leaves the second stage ready to be ignited so the rocket can be propelled through the upper atmosphere.

The second stage is named S-II and was designed and built by North American Aviation. The configuration of its engines is really similar to the first stage, having four at each corner (which can also be controlled to set the direction) and one at the center. However, one of the main differences resides on the engine that it is used, in this case the J2, which also uses different fuel. The J2 requires LH2 (liquid hydrogen) and LOX (liquid oxygen) to function. One of the most complicated aspects of the usage of LH2 as fuel is the necessity of keeping it just 20 ºC  above the absolute zero, which means that the tanks that contain it needed a full isolation.

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The S-II stage during stacking operations of Apollo 6 in the vehicle assembly building. Ordinarily the interstage would be attached to the S-II first. The flight stage was delayed, resulting in the interstage being attached to the S-IC instead. Image Credit: NASA.

 Finally, the last stage of the rocket is the only one that gets ignited twice during the trip. The first time it is turned on is to put the rocket into the Earth’s orbit, while the second one provides the actual impulse needed to go from the Earth’s orbit to the Moon’s one. This final stage was built by Douglas Aircraft Company.

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S-IVB-206 which was used for the Skylab 2 flight. Image Credit: NASA.

 After all these stages, there comes the Instrument Unit, a ring shaped component that is in charge of the measurements from the initial lift off until the detachment of the last stage. This monstrous computational machine was built by IBM and provides the guidance system of the rocket, as well as an emergency detector. By using accelerometers and inertial bodies as a frame it calculates the position of the Saturn V. At last, the part that is most seen in the popular media is where the astronauts are and, as much as it is famous, it is really just a tiny fraction of the whole rocket.

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Saturn V Schematic. Image Credit: NASA.

 When one look back and see the traces of what the Saturn V has led to, it is very clear how it has built a path in the aeronautics field. No matter how much the NASA has changed after the firsts Saturn V experiments, the rocket is still the most powerful one currently being used. Also, it is important to note that, in spite of how the USA has gained pride in being the first country to land a man in the Moon, the design of the Saturn V was from a team lead by Wernher von Braun, and at its core there is an antecedent of Nazi technological research. Everything, from the historical and political context to the scientific advances it implied are relevant to today’s world.

References

NASA. 2017. 50 years ago: The First Flight of the Saturn V. Available at: https://www.nasa.gov/feature/50-years-ago-the-first-flight-of-the-saturn-v

Space. 2017. 10 Surprising Facts About NASA’s Mighty Saturn V Moon Rocket. Available at: https://www.space.com/38720-nasa-saturn-v-rocket-surprising-facts.html

 Wikipedia. 2018. Saturn V. Available at: https://en.wikipedia.org/wiki/Saturn_V

 _. 2018. RP-1. Available at: https://en.wikipedia.org/wiki/RP-1

_. 2018. Wernher von Braun. Available at: https://en.wikipedia.org/wiki/Wernher_von_Braun

 

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Author: Jesus Padilla

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