The Saturn family of American rockets was developed by a team led by Wernher von Braun and other former Peenemünde employees to launch heavy payloads to Earth orbit and beyond. The Saturn family used liquid hydrogen as fuel in the upper stages. Originally proposed as a military satellite launcher, they were adopted as the launch vehicles for the Apollo Moon program. Three versions were built and flown: the medium-lift Saturn I, the heavy-lift Saturn IB, and the super heavy-lift Saturn V.
Von Braun proposed the Saturn name in October 1958 as a logical successor to the Jupiter series as well as the Roman god's powerful position.
In 1963, President John F. Kennedy identified the Saturn I SA-5 launch as being the point where US lift capability would surpass the Soviets, after having been behind since Sputnik. He last mentioned this in a speech given at Brooks Air Force Base in San Antonio on the day before he was assassinated.
The Saturn V was the first of two launch vehicles to transport human beings beyond low Earth orbit, the other being the Space Launch System (SLS). A total of 24 humans were flown to the Moon in the four years spanning December 1968 through December 1972. No Saturn rocket failed catastrophically in flight,historicspacecraft.com, Saturn I & IB Rockets except on the pad during the Apollo 1 test flight, when a fire ignited in the crew module, killing all of the astronauts on board.
Summary of variants All the Saturn family rockets are listed here by date of introduction.
NameSerial numberFunctionMaiden flightFinal flightLaunchesRemarksTotalSuccessFailureSaturn I Block ISA–1–4DevelopmentOctober 27, 1961March 28, 1963440Live first stage onlySaturn I Block IISA–5–10DevelopmentJanuary 29, 1964July 30, 1965660Carried Apollo boilerplate CSM and Pegasus micrometeoroid satellitesSaturn IBSA–200Apollo spacecraft Earth orbital carrierFebruary 26, 1966July 15, 1975990Used for Apollo 7, Skylab crews and Apollo–Soyuz Test ProjectSaturn VSA–500Apollo spacecraft lunar carrierNovember 9, 1967May 14, 197313121Launched nine crewed lunar missions and the Skylab space station
History
Early development In the early 1950s, the US Navy and US Army actively developed long-range missiles with the help of German rocket engineers who were involved in developing the successful V-2 during the Second World War. These missiles included the Navy's Viking, and the Army's Corporal, Jupiter and Redstone. Meanwhile, the US Air Force developed its Atlas and Titan missiles, relying more on American engineers.
Infighting among the various branches was constant, with the United States Department of Defense (DoD) deciding which projects to fund for development. On November 26, 1956, Defense Secretary Charles E. Wilson issued a memorandum stripping the Army of offensive missiles with a range of or greater, and turning their Jupiter missiles over to the Air Force.Cadbury (2006), p. 154 From that point on, the Air Force would be the primary missile developer, especially for dual-use missiles that could also be used as space launch vehicles.
In late 1956, the Department of Defense released a requirement for a heavy-lift vehicle to orbit a new class of communications and "other" satellites (the spy satellite program was top secret). The requirements, drawn up by the then-unofficial Advanced Research Projects Agency (ARPA), called for a vehicle capable of putting 9,000 to 18,000 kilograms into orbit, or accelerating 2,700 to 5,400 kg to escape velocity.Bilstein (1996), p. 25.
Since the Wilson memorandum covered only weapons, not space vehicles, the Army Ballistic Missile Agency (ABMA) saw this as a way to continue the development of their own large-rocket projects. In April 1957, von Braun directed Heinz-Hermann Koelle, chief of the Future Projects design branch, to study dedicated launch vehicle designs that could be built as quickly as possible. Koelle evaluated a variety of designs for missile-derived launchers that could place a maximum of about 1,400 kg in orbit, but might be expanded to as much as 4,500 kg with new high-energy upper stages. In any event, these upper stages would not be available until 1961 or 1962 at the earliest, and the launchers would still not meet the DoD requirements for heavy loads.H. H. Koelle et al., "Juno V Space Vehicle Development Program, Phase I: Booster Feasibility Demonstration", ABMA, Redstone Arsenal, Report DSP-TM-10-58, October 13, 1958
In order to fill the projected need for loads of 10,000 kg or greater, the ABMA team calculated that a booster (first stage) with a thrust of about thrust would be needed, far greater than any existing or planned missile.Neufeld (2007), p. 331 For this role they proposed using a number of existing missiles clustered together to produce a single larger booster; using existing designs they looked at combining tankage from one Jupiter as a central core, with eight Redstone diameter tanks attached to it. This relatively cheap configuration allowed existing fabrication and design facilities to be used to produce this "quick and dirty" design.
Two approaches to building the Super-Jupiter were considered; the first used multiple engines to reach the mark, the second used a single much larger engine. Both approaches had their own advantages and disadvantages. Building a smaller engine for clustered use would be a relatively low-risk path from existing systems, but required duplication of systems and made the possibility of a stage failure much higher (adding engines generally reduces reliability, as per Lusser's law). A single larger engine would be more reliable, and would offer higher performance because it eliminated duplication of "dead weight" like propellant plumbing and hydraulics for steering the engines. On the downside, an engine of this size had never been built before and development would be expensive and risky. The Air Force had recently expressed an interest in such an engine, which would develop into the famed F-1, but at the time they were aiming for and the engines would not be ready until the mid-1960s. The engine-cluster appeared to be the only way to meet the requirements on time and budget.
Super-Jupiter was the first-stage booster only; to place payloads in orbit, additional upper stages would be needed. ABMA proposed using either the Titan or Atlas as a second stage,Neufeld (2007), p. 341. optionally with the new Centaur upper-stage.Dawson & Bowles (2004), p. 24. The Centaur had been proposed by General Dynamics (Astronautics Corp.) as an upper stage for the Atlas (also their design) in order to quickly produce a launcher capable of placing loads up to into low Earth orbit.Dawson & Bowles (2004), pp. 22–24. The Centaur was based on the same "balloon tank" concept as the Atlas, and built on the same jigs at the same diameter. As the Titan was deliberately built at the same size as well, this meant the Centaur could be used with either missile. Given that the Atlas was the higher priority of the two ICBM projects and its production was fully accounted for, ABMA focused on "backup" design, Titan, although they proposed extending it in length in order to carry additional fuel.
In December 1957, ABMA delivered Proposal: A National Integrated Missile and Space Vehicle Development Program to the DoD, detailing their clustered approach."Proposal: A National Integrated Missile and Space Vehicle Development Program", ABMA, Redstone Arsenal, Report D-R-37, December 10, 1957 They proposed a booster consisting of a Jupiter missile airframe surrounded by eight Redstones acting as tankage, a thrust plate at the bottom, and four Rocketdyne E-1 engines, each having of thrust. The ABMA team also left the design open to future expansion with a single engine, which would require relatively minor changes to the design. The upper stage was the lengthened Titan, with the Centaur on top. The result was a very tall and skinny rocket, quite different from the Saturn that eventually emerged.
Specific uses were forecast for each of the military services, including navigation satellites for the Navy; reconnaissance, communications, and meteorological satellites for the Army and Air Force; support for Air Force crewed missions; and surface-to-surface logistics supply for the Army at distances up to 6400 km. Development and testing of the lower stage stack were projected to be completed by 1963, about the same time that the Centaur should become available for testing in combination. The total development cost of $850 million during the years 1958-1963 covered 30 research and development flights.Ivan Ertel and Mary Louise Morse, "The Apollo Spacecraft – A Chronology" , NASA Special Publication-4009
Sputnik stuns the world
While the Super-Jupiter program was being drawn up, preparations were underway for the first satellite launch as the US contribution to the International Geophysical Year in 1957. For complex political reasons, the program had been given to the US Navy under Project Vanguard. The Vanguard launcher consisted of a Viking lower stage combined with new uppers adapted from sounding rockets. ABMA provided valuable support on Viking and Vanguard, both with their first-hand knowledge of the V-2, as well as developing its guidance system. The first three Vanguard suborbital test flights had gone off without a hitch, starting in December 1956, and a launch was planned for late 1957.
On October 4, 1957, the Soviet Union surprised the world with the launch of Sputnik I. Although there had been some indications that the Soviets were working towards this goal, few in the U.S. military and scientific establishment considered these efforts seriously.
When asked in November 1954 about the possibility of the Soviets launching a satellite, Defense Secretary Wilson replied: "I wouldn't care if they did.""Project Vanguard, Why it failed to live up to its name", Time magazine, October 21, 1957 The public did not see it the same way, however, and the event was a major public relations disaster for the US. Vanguard was planned to launch shortly after Sputnik, but a series of delays pushed this into December, when the rocket exploded in spectacular fashion. The press was harsh, referring to the project as "Kaputnik"International Herald Tribune front-page headline, December 8, 1957 or "Project Rearguard". As Time magazine noted at the time:
But in the midst of the cold war, Vanguard's cool scientific goal proved to be disastrously modest: the Russians got there first. The post-Sputnik White House explanation that the U.S. was not in a satellite "race" with Russia was not just an after-the-fact alibi. Said Dr. Hagen ten months ago: "We are not attempting in any way to race with the Russians". But in the eyes of the world, the U.S. was in a satellite race whether it wanted to be or not, and because of the Administration's costly failure of imagination, Project Vanguard shuffled along when it should have been running. It was still shuffling when Sputnik's beeps told the world that Russia's satellite program, not the U.S.'s, was the vanguard.
Von Braun responded to Sputnik I's launch by claiming he could have a satellite in orbit within 90 days of being given a go-ahead. His plan was to combine the existing Jupiter C rocket (confusingly, a Redstone adaptation, not a Jupiter) with the solid-fuel engines from the Vanguard, producing the Juno I. There was no immediate response while everyone waited for Vanguard to launch, but the continued delays in Vanguard and the November launch of Sputnik II resulted in the go-ahead being given that month. Von Braun kept his promise with the successful launch of Explorer I on 1 February 1958. Vanguard was finally successful on March 17, 1958.
ARPA selects Juno