“The Saturn V launch vehicle is big. Really big. You just won’t believe how vastly hugely mindbogglingly big it is. I mean you may think it’s a long way down the road to the chemist’s, but that’s just peanuts to the Saturn V launch vehicle.”
Actually Douglas Adams was referring to Space in this quote from “The Hitchhiker’s Guide to The Galaxy” but he might as well have been talking about the liquid fuelled American behemoth which, having checked on Google Earth, would stretch from my house to the nearest Co-Op and would only have fitted just over two and a half times in the distance to Badham’s Chemist in St John’s Avenue.
Or put another way, the Saturn V – which launched the Apollo missions to the Moon – was 363 feet tall. Thirty six storys. Just twelve inches shorter than St Paul’s Cathedral in London or sixty feet taller than New York’s Statue of Liberty.
Or put another way, even the 1/144 Airfix model that Jet Age member Tim Mansfield has kindly given me to take part in my forthcoming Goes Like A Rocket presentation is so tall that I had to use the sky board normally used for the Joint Harrier Strike Force set on end as a background for the pictures on this page!
The lowest (S-1C) stage alone could almost swallow the Russian R-7 rocket that launched Sputnik 1, the first Earth orbit satellite, in 1957. And each of the four boosters strapped on to the core of that Communist built launcher itself was taller than the Nazi V2 missile which spawned both the R-7 and Saturn V in World War II.
Fully fuelled for lift off, the Saturn V weighed 2 950 tonnes and generated 3 400 tonnes of thrust, more power than 85 Hoover dams. It could launch 125 tonnes to low Earth orbit or 46 tonnes to the Moon and remains the tallest, heaviest and most powerful operational rocket ever. It is also the only launch vehicle to take astronauts beyond Earth orbit. However, the whole Saturn V did its job in less than half an hour from launch to orbit.
The story of America’s Saturn V can be traced to the arrival of Werner von Braun and about 700 of his Nazi rocket scientist colleagues in New Mexico in 1946. Operation Paperclip was designed to harvest the expertise that had produced Germany’s V2 ballistic missile and during the 1950s von Braun worked on ever more proven and advanced designs for the US Army at its Redstone Arsenal at Huntsville Alabama. These included the Juno rocket which the freshly formed NASA used to launch America’s first satellite in 1958.
As such, from 10 January 1962, von Braun was able to meet NASA’s design brief for a rocket to carry a 40 tonne payload to the Moon. Initially known as the C5 until 1963, this launch vehicle would comprise three stages – an arrangement first imagined by Russian space visionary Konstantin Tsiolkovsky and patented by American liquid fuelled rocket pioneer Robert H. Goddard.
The lowest of these – and firing first – was what became known as Stage S1-C. This was ultimately built by Boeing around five Rocketdyne F-1 engines which burned liquid oxygen and RP-1 kerosene fuel – as had the V-2. The height of the roof at Boeing’s Michoud Assembly Facility near New Orleans determined the 33′ diameter of Stage S-1C and thereby the whole launch vehicle. The first test of all five engines of Stage S-1C took place at Marshall Spaceflight Center, within Huntsville’s Redstone Arsenal on 16 April 1965.
The second – S-II – stage was built by North American Rockwell Aviation at Seal Beach, California and featured five Rocketdyne J-2 engines, also arranged in a quincunx. The S-II was in fact the last of the three Saturn V stages to be designed and had to be particularly light but strong. Weight saving techniques included the fuel and oxidant tanks of the S-1C being replaced by a monocoque tank structure in which the base of the bottom of the hydrogen tank was also the top of the oxygen holder. The two chemicals were separated by a bulkhead formed of two aluminium sheets separated by a honeycomb structure made of phenolic resin. This honeycomb construction – and the use of phenolic resin – had been previously been used by the Bristol Aeroplane Company and the bulkhead – which had to withstand a temperature difference of 70 degrees centigrade between the two tanks – saved 3.6 tonnes compared to more orthodox techniques.
The third – S-IV – stage was built by Douglas Aircraft at Huntingdon Beach, also in California, and was powered by a single Rocketdyne J-2. The S-IV stage engine also had – uniquely among liquid oxygen / liquid hydrogen rockets – to be able to shut down and then re start in Earth orbit to allow its payload of Lunar, Command and Service Module to perform Trans Lunar Injection. This was achieved by using the Auxiliary Propulsion System units – mounted on the after end of Stage S-IV for attitude control during the orbit and TLI phases of the flight – to pressurise the remaining oxygen and hydrogen in the tanks so that they would flow to the combustion chamber and re-ignite on command.
Each stage had its own Propellant Dispersal System which could be remotely triggered by Cape Canaveral’s Range Safety Officer to destroy the rocket if it veered off course and threatened to harm life or property.
On top of Stage S-IV was the ring shaped Instrument Unit, built by IBM and assembled at the Space Systems centre at Huntsville and designed to control the Saturn V’s internal guidance, navigation and control and emergency range safety systems, electrical power, communications and environmental controls. This featured an early digital computer – one area in which the USSR lagged behind the USA -for flight system control and was a great advance on the one electrically powered gyroscope used to do the same job on the V2.
Finally, above the five ton Apollo Command Module, was the tower of the Launch Escape System which could have pulled the three astronauts clear of any launch pad explosion. This had a greater sea level thrust than the Redstone rocket which had powered Alan Shepherd -the first American in space in his Mercury spacecraft – on his sub orbital flight in 1961. On each Apollo Moon flight, the Launch Escape System was jettisoned after the S-1C stage and its interstage ring separated from the S-II stage.
Of the three stages, only the Douglas built S-IV was small and light enough to be flown to Cape Canaveral, Florida in special Guppy aircraft, the other two larger items having to arrive by sea. The S-IIs were shipped from California by way of the Panama Canal, the S-1Cs came down the Mississippi River and round the tip of Florida and each Saturn V “stack” was put together vertically at the Vehicle Assembly Building (VAB) three miles from the launch pad. The VAB could handle up to three stacks at a time and each Saturn V would leave mounted on a Mobile Launcher Platform (MLP) complete with Launch Umbilical Tower (LUT) aboard a giant Crawler Transporter. Built by the Marion Power Shovel Company and fitted with very accurate self-levelling suspension above four double tracked treads, each Crawler Transporter would then take the Saturn V, MLP and LUT on a causeway across the Banana River and leave it on the appropriate pad for final tests and fuelling.
First launched on 9 November 1967 and last launched on 14 May 1973, thirteen of the fifteen Saturn V vehicles built were sent into space at a cost per launch of $ 1.5 billion at 1966 prices ($ 16.8 billion in today’s money) or almost ten times the cost of the 1940s Manhattan Project to develop the atomic bomb.
Boeing’s 138′ long Stage IC worked for 161 seconds (2.7 minutes), burning 15 tons of fuel and oxidant a second and taking the whole rocket to an altitude of 38 miles and a speed of 6 000 miles per hour. This involved clearing the launch tower in twelve seconds and breaking the speed of sound in one minute at an altitude of over three miles.
To operate the turbo pumps – visible on the side of each F-1 engine bell – feeding fuel and oxidant to the combustion chambers of the five engines, the secondary Open Cycle Gas Generator rocket engine had to produce 55 000 shaft horsepower – more than 16 Deltic diesel locomotives. Within the quincunx, the centre engine was fixed while the other four could be gimballed to steer the rocket.
At this point explosive bolts and a set of eight retro rockets would have fired to separate it and its interstage ring from the S-II stage which would then have fired its engines for 390 seconds (six minutes), yielding 1 125 000 lb of thrust by way of an invisible exhaust to take the combined second and third stages and Apollo spacecraft to an altitude of 118 miles and a speed of 14 000 mph.
This sequencing of rocket stages relied on all components working precisely one after another in contrast to the Soviet R-7 rocket which had launched the first Sputnik in 1957. Both the central core engines of this launcher and those on the four strap-on boosters were ignited at launch, the boosters falling away during the ascent and only one further stage being fired at altitude to take the satellite into parking orbit.
Back on the soaring Saturn V, the S-IV stage would have taken over from the discarded S-II, firing its single J-2 engine first for a 2 minute 30 second orbital insertion burn and then – after a period of coasting in orbit – a six minute Trans Lunar Injection burn to take the spacecraft modules away from the gravity of the Earth and towards the influence of the Moon. Once the Command and Service Module (CSM) had extracted the Lunar Module from the S-IV and moved ahead of it, the third stage was then commanded to fly on a different trajectory to avoid collision.
This was either ultimately into orbit around the Sun or, on later Apollo missions, a collision course with the Moon – away from the selected LEM landing area so that seismographs set up by previous crews could detect the resulting “Moonquakes”. On 3 September 2002, astronomer Bill Yeung discovered a suspected asteroid, which was given the discovery designation J002E3. It appeared to be in orbit around the Earth, and was soon discovered from spectral analysis to be covered in white titanium dioxide, which was a major constituent of the paint used on the Saturn V. Calculation of orbital parameters led to tentative identification as being the Apollo 12 S-IVB stage. Mission controllers had planned to send Apollo 12’s S-IVB into solar orbit after separating from the Apollo spacecraft, but it is believed the burn lasted too long, and hence did not send it close enough to the Moon, remaining in a barely stable orbit around the Earth and Moon. In 1971, through a series of gravitational perturbations, it is believed to have entered in a solar orbit and then returned into weakly captured Earth orbit 31 years later. It left Earth orbit again in June 2003.
Although available thrust decreased with the deployment of each stage during ascent, efficiency of the Saturn V rocket engines increased as each stage boosted the remaining components to a higher speed above the drag of Earth’s atmosphere and with an ever lightening load as propellants burned off.
The final Saturn V launch was the only one not connected with the Moon landing programme and featured just S-1C and S-II stages launching the orbiting space station Skylab, built from a smaller Saturn 1B second stage. On this occasion the S-II stage was modified to finally insert Skylab into orbit and then vent its propellant into space, making it more inert as a piece of space junk until it re-entered the Earth’s atmosphere in 1975.
With NASA’s 1966 budget representing 0.5% of America’s GDP, sheer cost prevented more Saturn Vs being built and the concept being developed into even more powerful rockets that could have launched a re-usable winged Space Shuttle, sent large probes rapidly to other planets, built space stations in just a few launches and even deployed a nuclear engined third stage in orbit. As it is, with the Space Shuttle now retired, America’s latest heavy lift rocket project is the Space Launch System. This uses a mixture of liquid fuelled Space Shuttle Main Engines and solid boosters which are less controllable once lit and can -as was proved with the Challenger disaster – prove vulnerable to pre-launch frost damage.
However, it may be that the lower – and perhaps even upper – stages of future vertically launched cylindrical step rockets will be landed back on Earth in a controlled manner for further use. This concept has been tested by the SpaceX Corporation on the first stage of its Falcon 9 rocket which deploys four baffle-like steering wings at the top of its casing when it has separated from the upper stages of the rest of the launch vehicle. Despite promising solo tests at a land launch site – recorded on video above – the first stage of the Falcon 9 deployed on 10 January 2015 to send supplies to the International Space Station did not quite land correctly on the intended 300′ long drone barge off the coast of north east Florida. As a result, although the six ISS astronauts received the groceries they had been expecting since the autumn of 2014 – when another SpaceX rocket blew up at Wallops Island, Virginia – SpaceX founder Elon Musk was forced to conclude that his booster had landed too hard and that he would have to “piece it together with telemetry and …actual pieces. The ownership of the cattle in the video and the effect on them of witnessing a powered rocket landing has yet to be discerned!
Of the Saturn V rockets currently on display, only the one at Johnson Space Centre, Houston, Texas, is made up entirely of stages that could have flown. The Kennedy Space Centre, Florida, example has a test vehicle as its S-1C and the Huntsville “stack” ( laid on its side like the aforementioned two) is made entirely of test components. Huntsville’s US Space and Rocket Center also has an entirely replica Saturn V displayed vertically and there is an S1-C on display at Michoud, New Orleans and an S-IVB in the National Air and Space Museum in Washington DC.