I’ve previously mentioned that once the Shuttle program ends this year, there will be no way for NASA to launch manned missions. It simply doesn’t have the necessary rockets to launch such a heavy payload into orbit, let alone a rocket capable of launching a heavy payload to another planet. A good example is the case of Mars. The Delta II hit its payload limit with the Mars Exploration Rovers Spirit and Opportunity, and that’s with each rover launched separately. The upcoming Mars Science Laboratory rover Curiosity is significantly larger and will use an Atlas family launch vehicle. For NASA’s Martian exploration plan to progress, as well as for the continuation of manned spaceflight, the organization needs a heavy lifting vehicle. (Pictured, the first Saturn V to launch: Apollo 4, 1967.)
But NASA doesn’t necessarily need a new launch vehicle. The organization had the means to launch a manned mission to Mars in the 1960s using only technology of the day. The whole mission, however, depended on the titanic Saturn V rocket, a technology that is lost to the current generation.
The Saturn V was the brainchild of Wernher von Braun (pictured), the man behind the Nazi V-2 missile that rained down on London in the final days of the Second World War. In 1945, with the Germans defeated and the Allies closing in to collect the brightest Nazi scientists as a form of intellectual reparations, von Braun and his team of rocketeers surrendered themselves to the Americans. They hoped their expertise in rocketry would be their ticket to continued work. It was; von Braun hand-selected 110 men to move White Sands, New Mexico to join the Army Ballistic Missile Association (ABMA).
The German rocketeers worked on developing improved missile to launch the lightweight American warheads. But the Soviets soon proved the might of their rockets. The powerful R-7 launched the 182-pound Sputnik satellite followed a month later by the 1,120-pound Sputnik II. The US was well behind in brute force lifting vehicles; the first successful US satellite was the 30-pound Explorer 1. The launch vehicle was the von Braun-designed, 69.5 foot high Jupiter C. (Pictured, the Jupiter C rocket launches Explorer 1. 1958.)
As the space race quickly picked up steam in the late 1950s, von Braun and his team in New Mexico found themselves with a new project: building a more powerful launch vehicle than anything the US currently had.
To this end, the rocketeers set to work in 1960 developing a new family of missiles named Saturn – the new rocket built on the successful Jupiter family of missiles, and was given the name of the next furthest planet from Earth. Their headquarters also received a new name. The ABMA became NASA’s Marshall Spaceflight Centre (MSC) with von Braun as its first director.
The new Saturn family of rockets was tied to NASA’s long-term goals; though unofficial in 1960, the Moon was an objective. But to build a rocket capable of sending men to the moon, MSC engineers had to know how NASA intended to get there. There is more than one way to go to the moon, and each decision requires different capabilities of its launch vehicle. In preparing Apollo, NASA considered three options called mission modes.
The first mode is the brute force method of direct ascent. A mammoth rocket is required to send a spacecraft on a straight path from the Earth to the Moon. The spacecraft would also have to land and relaunch from the Moon making it heavy. Von Braun calculated that such a rocket would require around 12 million pounds of thrust at liftoff provided by eight engines. This method would require development of Nova, a missile of unparalleled power. (Pictured, a comparison of Saturn and Nova launch vehicles. Research into Nova development was cancelled in 1962 when the LOR mission mode was selected. This artist’s conception is from 1962.)
The second mode of Earth Orbit Rendezvous (EOR) uses two smaller rockets to assemble the same spacecraft in orbit around the Earth.
The third mode of Lunar Orbit Rendezvous (LOR) is the recognizable method that NASA used for the Apollo program. Two spacecraft would be launched on one powerful rocket, the lighter of which would land on the moon while the heavier stayed in lunar orbit. This significantly lightened the payload and simplified the launch vehicle. (Pictured, the Apollo 8 flight plan shows the basic Apollo mission profile. 1968.)
This method also brought an added safety measure to the lunar mission; it provided the astronauts with a stopping point in Earth orbit as well as lunar orbit. With more places to pause during a mission, there was more leeway to catch up on late manoeuvres as well as a safe place to double check the mission profile. If any problems were detected, the crew could be brought home from Earth or Lunar orbit much more easily than they could be from a lunar transit.
Within the developing Saturn family, only the Saturn V (so called as it was the fifth in the family) could launch the lunar spacecraft into Earth orbit then onto the Moon under its own power. At 364-feet tall, the three-stage rocket was the most powerful ever built.
The Saturn V’s stages (pictured) are the key to its power. The stages are stacked: the first stage on the bottom, the second stage on top of the first, and the third stage on top of the second. Above the third stage is the spacecraft. The stages burn and are discarded in sequence; as spent pieces of the rocket fall away, the payload headed towards the moon became increasingly lighter and easier to lift.
The first stage (called the S-IC, pictured with MSC engineers) provided the raw power. Two huge tanks, one containing 800,000 litres of refined kerosene the other 1.3 million pounds of other liquid oxygen (LOX), fuel five powerful engines. These engines produce 7.5 million pounds of thrust for about two and a half minutes, bringing the spacecraft to an altitude of about 38 miles. Once exhausted, the first stage falls away and the second stage takes over.
The second stage (called the S-II) burns for about six minutes, producing 1 million pounds of thrust from its five liquid hydrogen and LOX fuelled engines. The second stage shoots the spacecraft to an altitude of about 114 miles before it falls away exhausted.
The third stage (S-IVB) fires last and is responsible for propelling only the spacecraft. Its liquid hydrogen and LOX-fuelled engine fires twice; once for 2.75 minutes to bring the spacecraft to an altitude of 115 miles, and again for 5.2 minutes to initiate the lunar transit. With the final firing of the S-IVB, the Apollo crew is on their way to the moon.
While its three stages were responsible for the Saturn V’s spectacular power, it wasn’t the only factor that made it such a sophisticated launch vehicle. It also had a certain degree of autonomy. The brain of the Saturn V was its instrument unit, a ring of computerized components situated above the third stage. This included a digital computer, a stabilized guidance platform, and sequencers. (Pictured, a cutaway of the Saturn V’s instrument unit.)
The rocket was able to guide itself into orbit and readjust its trajectory to achieve the orbital insertion point specified by the mission profile. Directional control was achieved through the first stages’ engine configuration. The central engine was fixed, but the outer four were on gimbals and could swivel to direct the rocket’s thrust in the desired direction.
This level of control was due to the rockets inertial guidance system. Like the Apollo spacecraft, the Saturn V was aligned to the stars rather than any point on Earth. It used ‘fixed’ stars to orient itself. The Saturn V’s own guidance system wasn’t only responsible for a successful orbital insertion; this was the guidance that shot the Apollo crew towards the moon with the translunar injection or TLI burn.
The idea was that separating the rocket’s computer and guidance systems from that of the spacecraft would provide an added redundancy. Apollo’s onboard computer could control and steer the Saturn V – the Command Module (CM) was also aligned to the ‘fixed’ stars for guidance with its own inertial guidance platform. But in the event Apollo’s computer failed, NASA would have a potentially rogue Saturn V on its hands. With separate guidance systems, the crew was almost guaranteed a safe arrival into orbit at which point any problems could be addressed.
This proved to be a fortunate decision. When lightening struck Apollo 12 soon after launch (pictured), the CM’s guidance system and computers were knocked off line. The Saturn V’s systems, however, were unscathed. The crew and mission control were able to correct the problem in the spacecraft knowing they were still safely on course for orbit where an emergency abort and splashdown was simpler and safer.
The Saturn V’s sophistication also makes it a complicated piece of technology. There are a lot of parts that have to function independently while simultaneously working together as a cohesive unit. And so von Braun, as the rocket’s designer and director of the MSC, had to answer the same question that faced every new aspect of the space program: who would build it?
In the case of the Saturn V, the question was not only which subcontractor would build it, but how many. Should one contractor build the whole thing or should each stage be built by a different contractor? What about the instrumentation unit, the onboard computer, as well as the telemetry and radio systems? If each piece was made by a different contractor, who would oversee the final assembly and testing of the completed launch vehicle?
Von Braun made the decision to give each piece of the rocket to a different contractor, a decision that yielded mutual gain. From the contractors’ standpoint, multiple companies were able to benefit financially as well as partake in the challenge of building the Saturn V. From von Braun’s perspective, it enabled him to pull together the best in the industry; the top men from each company worked towards building his launch vehicle.
Three main companies were awarded Saturn V contracts. Boeing built the first stage, North American Aviation (who built the X-15 and the Apollo CM) built the second stage, and Douglas Aircraft built the third stage. The inertial guidance system and instrumentation was built in-house by the Marshall Spacecraft Centre – it made sense to keep the brains of the rocket close to the men who would control it during a launch. (Pictured, the Saturn V with each section labelled by subcontractor.)
To simplify the oversight of proceedings around the Saturn V’s construction, von Braun created two groups within the MSC. The Research and Development Operations team became the architects overseeing the rocket’s integrity and structure, and the Industrial Operations team funded and oversaw the subcontractors.
The Saturn V was completed at an impressive speed. Construction began in 1960. Each element was tested individually before the first launch of a complete Saturn V in 1967, which launched an unmanned Apollo CSM as payload. There was no time to waste a launch using a dummy spacecraft or a water tank as ballast. Everything had to advance the goal of the lunar landing.
After only two unmanned launches, the third Saturn V took Apollo 8 to the moon.
The Saturn V fell out of favour with NASA in the mid-1970s; Apollo was no longer a viable program and NASA had begun to favour the reusable low Earth orbital space shuttle. There were no immediate plans to return to the Moon or any foreseeable need for such a powerful launch vehicle. In the intervening nearly 40 years, the technology behind the Saturn V has been all but lost. (Right, the launch of Apollo 8. 1968.)
The division of labour on the Saturn V’s construction proved, in retrospect, to be a double-edged sword. On the one hand, it allowed the rocket to be completed at an incredible rate, certainly responsible for the success of the Apollo program.
But on the other hand, building the rocket at such a rate and with so many subcontractors means the people who oversaw and understood the actual assembly and overall working of the Saturn V were few. Each contractor recorded the workings of their stage and records survive about the engines used, but only a handful of engineers from the MSC knew how Saturn V puzzle fit together.
It is possible to work backwards to recreate individual aspects of the technology, but the men who knew how the whole vehicle worked are gone. No one alive today is able to recreate the Saturn V as it was.
Worse is the lack of records. Without a planned used for the Saturn V after Apollo, most of the comprehensive records of the rockets inner workings stayed with the engineers. Any plans or documents explaining the inner workings of the completed rocket that remain are possibly living in someone’s basement, unknown and lost in a pile of a relative’s old work papers.
Two Saturn Vs remain today as museum pieces, but it is likely that the rocket will never see a rebirth and reuse in manned spaceflight.
Yes, NASA put men on the moon with 1960s technology, but that technology doesn’t exist anymore. By default, neither does the possibility of a manned lunar or Martian mission for that matter without a new launch vehicle. A new heavy lifting vehicle will eventually come about – it will have to for NASA to pursue its longer-term goals. Until then, NASA is bound to low Earth orbit and minimal interplanetary unmanned spacecraft.
Selected Sources/Suggested Reading
1. Homer E. Newell. Beyond the Atmosphere. Dover: New York. 2010
2. W. David Woods. How Apollo Flew to the Moon. Springer Praxis: UK. 2008.
3. Edgar M. Cortright ed. Apollo Expeditions to the Moon. Dover: New York. 2009.
The live CBS footage with Walter Cronkite of the first Saturn V launch – the Apollo 4 unmanned mission, 1967. You can hear him describing the rockets effect on the building. Pretty good indicator of its power.
Dramatization of the Apollo 12 launch from “From the Earth to the Moon” - a great mini series from Tom Hanks well worth watching. This is from the seventh episode “That’s All There Is”, 1998.