Space Travel

Part 4 - Saturn V in Eleven Easy Steps

Ross, Going Postal

It is the 7th May 1945 and on this spring morning in the Bavarian mountains, a few days after the death of Hitler, the soldiers of the 44th infantry division that are manning a checkpoint have no idea that the young man in civilian clothes cycling towards them is going involve them in one of the most significant events in the as yet unimagined US space programme.

The young man is Magnus von Braun, brother of Wernher, and he was sent as an emissary from a large group of V2 developers keeping their heads down in a nearby Ski resort called Oberjoch. Magnus has been chosen because he has the best English and, well because brutally he is the most expendable – ah the Germans!

The story of the group’s departure from Peenemunde and subsequent travel to the States would make a good spy novel – including using a spelling mistake in their orders to allow them to pretend to be on an imaginary special mission and the hiding of 14 tons of documents in a mine in the Bavarian alps. The Russians even broadcast public pleas to the engineers to join them from the Russian controlled sector of Germany with promises of good treatment and housing.

All of the major war powers knew that the German advances in rocketry were ahead of the rest of the World, and whilst the British and French were more interested in seeing who needed to be imprisoned for war crimes (both being on the receiving end of the V2) the Russians and Americans were desperate to grab equipment, rocket parts, documents and engineers.

At the start of the twentieth century there were significant developments in rocketry in each of Russia, America and Germany; by Tsiolkovsky (he of the rocket equation) in Russia, Goddard (he of the space centre) in America and Oberth (he of the effect) in Austria – all three started looking at liquid fuelled rockets. Black powder solid rockets had been in military use for hundreds of years (aside: the star spangled banner includes the line “the red rockets glare” which was a reference to the British Navy rocket bombardment of Fort McHenry in the war of 1812), but as Artillery had developed to allow massive shells to be delivered over very long ranges almost all countries had abandoned black powder rocket research. So these individuals largely worked alone and often unfunded.

But it was the Germans that really pushed the world on.

There were two significant factors that pushed Germany to the forefront of research and that made it the leading nation in rocketry. The first of these was popular enthusiasm for space travel a spark ignited by a young Herman Oberth.

Oberth wrote a doctoral thesis on space travel in 1922 but the University of Heidelberg rejected it as being too fanciful – so he published it as a pamphlet “Die Rakete zu den Planetenräumen” (“By Rocket into Planetary Space”) initially 90 pages then reworked and made more accessible, it was a seminal work that fired the imagination of many. Max Valier was one of those inspired and he and others founded the  Verein für Raumschiffahrt (space travel society) in a pub in Breslau in 1927. This society was was more than just a talking shop it actually wanted to build rockets and it managed to recruit more than 500 members. Valier himself died whilst experimenting with an early liquid fuelled engine on a test stand – it blew him up as he tried to light it in 1930.

Oberth joined the VfR in 1929 and the group acquired the rights to use an old ammunition dump in Berlin as a base to build and test rockets. The famous film director Fritz Lang read Oberth’s book and commissioned him to be a consultant for the film Frau im Mond (Woman in the moon) to make it as technically accurate as he could, in a strange way this piece of fiction rendered a subsequent reality.

Ross, Going Postal

The film company asked Oberth and the VfR to build a liquid fuel rocket as publicity stunt; they failed to do this in time but it gave them a start and another member (Rudolf Nebel) secured funding from the Reichsinstitute for chemistry and technology to do further development. Oberth recruited a teenage Wernher Von Braun, an avid astronomer from a wealthy family, to work on rocket building.

The society’s first two rockets The Mirak and the Repulsor had several hundred launches but were tiny things little bigger than a large firework weighing only around 20Kg.

Ross, Going Postal
Reidel holding a Mirak with a young von Braun standing just behind him to the right of the photo and Oberth standing just to the left of Reidel in the dark coat

This tiny rocket that used a long stick for stability just like the ones you light of firework night – was just the first of eleven generations of von Braun rockets the final one being the 363 foot tall Saturn V that took man to the moon.

The group had both practical and theoretical minds and that allowed significant development (when they weren’t landing a rocket on and setting fire to a local police building – oops), but money was also short especially given it was Germany in the early 1930s, they knew what they’d like to experiment with but didn’t have the funds to build it.

The second factor that pushed Germany to the front of the rocketry world was the Treaty of Versailles – a treaty which had strict conditions on German artillery but didn’t mention rockets. Thus the German army had a unique interest in rocketry – so it was that in 1932 Captain Dornberger of the German Army turned up at the VfR to have a look what they were doing, they showed him a Mirak and launched it, but he was not as  impressed with the VfR as an organisation as he was with von Braun as an Engineer. So he offered von Braun a position working on rockets with a budget for development – von Braun took a number of VfR members with him to the German Army development team and immediately set to work on what was deemed the Aggregat-1 or A1.

The motor underwent a first test only a few months after von Braun joined, but it wasn’t a success – on the 21st December – it exploded on ignition (in an error just like Valier – the small gap between opening the valves and igniting the mixture allowed a build up of propellant).

At 1.4 meters in length and weighing in at just over 100Kg with 3000N of thrust, this was a substantially bigger and more sophisticated vehicle than the tiny Mirak. It had regenerative cooling (pumping the cold propellant in pipes around the outside of the combustion chamber and nozzle to stop them from melting) and it had a single axis flywheel gyroscope to try and stabilise it. Artillery shells are stabilised by rotating the whole thing, this isn’t possible in a liquid fuelled rocket as the propellant is pushed to the side-walls of the tanks.

The A1 was a failure but a fairly modest redesign produced the A2 which was nearly identical externally, but which moved the gyro to the middle of the rocket rather than the tip (along with some other changes) two were constructed and fired at the end of 1934 getting to a height of between 2 and 2.5Km.

While the A2 was being built and tested, the A3 was being designed, it was significantly bigger and had a much improved engine and aerodynamics – importantly it had a three axis gyro controlling active guidance (jet rudders/thrust vectoring) – it was also designed to be supersonic.

In the video below you can see the same sort of thrust vectoring system is being tested in the A5 prototype at about 50 seconds. Building an active inertial guidance system in the 1930s was extremely advanced –  it always seems quite a stretch to believe inertial guidance systems can work at all – and indeed the version in the A3 had catastrophic problems. The A4 (the rocket that we now call the V-2)  was on the drawing board by this stage and so a redesign of the smaller A3 with a new guidance system was labelled the A5 even though it ended up flying before the A4. The A5 rockets were flown from 1938 onward and reached altitudes of 12Km. The A5 brought together the technology needed to get into space from engine design through to aerodynamics – even though it was funded by an evil regime, it was a remarkable piece of engineering development only 6 years and five generations of rocket after the tiny Mirak.

Once the A5 had flown, the A4 (V-2) design was then modified to encompass the lessons from the smaller A5 and was first flown in 1942.

After the war both the Americans and Russians flew V2s and manufactured both parts and whole rockets. A number of variants were built and the first ever primate to reach space was on the top of a modified V-2 in 1948. The rhesus monkey Alfred II achieved 134Km altitude, unfortunately the parachutes failed so he didn’t have long to “enjoy” the accolade – Alfred I sadly suffocated on the launch pad.

von Braun and his team were initially sidelined once they got to America as other military teams vied to build rockets, but when it was realised after a few years that things weren’t going very well von Braun was made head of the Army guided missile team – and there developed the Redstone rocket – which was widely recognised as a direct successor to the V-2, it first flew in 1953, it was a relatively short range nuclear missile; About a third as big again as a V-2 but with a lot of similarities including the same alcohol/LOx fuel mixture and a similar thrust vectoring system.

After one failure to launch an early Redstone (it sat on the pad but had disconnected itself) – Chris Kraft (a senior Nasa figure) asked on the radio loop “what has gone wrong” several replies came over the radio – they were all in German.

In the mid 1950s von Braun and several others from the V2 programme were asked to explain more about space travel to the American public. Aside from a series of magazine articles – they appeared in a number of Disney specials for ABC where von Braun was introduced to 40million watching Americans by Walt Disney himself.

For von Bran and his team, there followed various iterations of the Redstone design – firstly Jupiter/Juno variants which put the first American satellite into space four months after Sputnik – this itself was an amazing feat as it was a design literally completed in weeks after the US Navy’s Vanguard had endless delays (what was the Navy doing building rockets anyhow?) , and then a further evolution to the Mercury Redstones that made the first US manned space flight with Alan Shepard.

The finally there were the Saturn boosters, the Saturn 1 that was an evolution of the Juno and then finally the crowning glory the Saturn V.

In one working lifetime and over around 11 generations this evolutionary sequence of rockets went from something that looked like a toy and had a ceiling of around 250m to a behemoth that took man to the moon.

Footnote: I have concentrated on the development of rockets and not on the moral or human costs of that work or even on the question of how culpable von Braun and his colleagues were for the misery they produced. The group were probably not hard bitten Nazi’s; von Braun was even imprisoned for a while by the Gestapo. Many of them they were driven by a desire to get into space rather than establish a Third Reich. The rockets they designed were, nonetheless, used as a last gasp attempt to preserve Hitler’s terrible regime and the building of them at Mittelwerk produced more deaths and horrors for the slave labour force than even their intended targets.
 

© Ross 2018
 

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