Saturn I
Wernher von Braun's team at the U.S. Army Ballistic Missile Agency began studying a heavy-lift vehicle in April 1957. They calculated that a rocket with the required performance would need about 1.5 million pound-force of thrust at takeoff. The Air Force had recently started work on an engine called the F-1, but it would not be available in time for their demands. Another possibility was a Rocketdyne engine known as the E-1, which provided about 300,000 pounds of thrust each. Four of these engines would reach the required thrust levels and became the favorite option. This approach paired eight H-1 engines with a first stage built from nine tanks placed atop a thrust plate. The design envisaged eight rocket tanks similar to the Redstone stage strapped around a central larger tank derived from a Jupiter rocket. Contrary to what was reported to the press, the tanks were not simply older designs but much longer versions built anew at the same diameter. Critics jokingly referred to this configuration as Cluster's Last Stand, a play on the nickname for the Battle of the Little Bighorn. Von Braun returned the design to the Department of Defense in December 1957 as A National Integrated Missile and Space Vehicle Development Program. Several variations were proposed using a common clustered first stage and upper stages based on either the Atlas or Titan I rockets. ABMA favored the Titan because its production was extremely high-priority and there was little excess capacity to spare.
The S-I first stage was powered by eight H-1 rocket engines burning RP-1 fuel with liquid oxygen as oxidizer. The propellant tanks consisted of a central Jupiter rocket tank containing LOX surrounded by a cluster of eight Redstone rocket tanks. Four painted white contained LOX while four painted black contained the RP-1 fuel. On Block II vehicles like SA-5 through SA-10, eight fins provided aerodynamic stability during flight through the atmosphere. The S-IV second stage was powered by six RL10 rocket engines burning liquid hydrogen with LOX as oxidizer. These engines were mounted on gimbals allowing them to steer the vehicle. The propellant tanks used a single common bulkhead to separate the LOX and LH2 propellant tanks saving 20% of structural weight. The S-V third stage was intended to be powered by two RL-10A-1 engines burning liquid hydrogen as fuel and liquid oxygen as oxidizer. This stage was flown four times on missions SA-1 through SA-4 but all had tanks filled with water for ballast. It never flew an active configuration on any Saturn launch vehicle. The Saturn I Instrument Unit carried guidance instruments in canisters on top of the S-I first stage for early flights. Later versions included the ST-90 stabilized platform made by Ford Instrument Company and used in the Redstone missile. Beginning with SA-5, guidance instruments were carried on the instrument unit just ahead of the S-IV stage.
The formation of NASA on the 29th of July 1958 led to an effort to collect existing heavy-launch rocket programs. At that time both the Air Force and US Army had teams developing such vehicles including the Army's Saturn and the Air Force's Space Launching System. Von Braun was asked to chair a committee to study existing efforts and write up recommendations. The committee presented their report on the 18th of July 1958 criticizing how the US program had been mishandled to date. They pointed out that the Soviet program was definitely ahead. In December 1958 all teams gathered to present their designs. NASA selected von Braun's proposal on the 6th of January 1959 giving it vital boost. Then unexpectedly on the 9th of June 1959 Herbert York Director of Department of Defense Research and Engineering announced he decided to terminate the Saturn program. He later stated he was concerned the project was taking ARPA money from more pressing projects. ABMA commander John B. Medaris noted his nose began sniffing a strange odor of fish as they investigated what was going on. A three-day meeting between 16 and the 18th of September 1959 followed where York and Dryden reviewed Saturn's future. York agreed to defer cancellation but only if NASA agreed to take over the ABMA team without DoD help. By a presidential executive order on the 15th of March 1960 ABMA became NASA's George C. Marshall Space Flight Center.
The Saturn I made its maiden flight on the 27th of October 1961 with a dummy upper stage and partially fueled first stage. Tension in the blockhouse was high since no launch vehicle had succeeded on the first attempt before. Three more flights with dummy upper stages followed over the next 17 months all completely or mostly successful. Two of them had the S-IV filled with water and detonated at high altitude after stage separation to form an ice cloud. Flight five in January 1964 was the first to carry a live S-IV which restarted its engine in orbit. Another two flights followed during that year with boilerplate Apollo Command and Service Modules. The final three also carried Pegasus micrometeoroid satellites in the second stage-spacecraft adapter. Ten Saturn I rockets were flown before it was replaced by the heavy lift derivative Saturn IB. SA-1 reached an apogee of 136.5 kilometers while SA-2 released 86,000 kilograms of water at an apogee of 145 kilometers. SA-3 achieved an apogee of 167 kilometers releasing another 86,000 kilograms of water. SA-5 became the first to orbit reaching 760 by 264 kilometers. SA-6 marked the first Apollo boilerplate CSM launch into an orbit of 204 by 179 kilometers.
President John F Kennedy identified the Saturn I and specifically the SA-5 launch as the point where US lift capability would surpass the Soviets. This assessment came after being behind since Sputnik. Newsreel reports captured JFK pointing at the Saturn I rocket at Cape Canaveral on the 16th of November 1963 weeks prior to its launch. His speech at Brooks Air Force Base on the 21st of November 1963 occurred on the last full day of his life. The Saturn I proved sound and flexible initiating development of liquid hydrogen-fueled rocket propulsion. It launched Pegasus satellites and provided flight verification for Apollo command and service module aerodynamics. Ten Saturn I rockets were flown before it was replaced by the heavy lift derivative Saturn IB. That derivative used a larger higher total impulse second stage and improved guidance control system. It also led way to development of super-heavy lift Saturn V which carried first men to landings on Moon in Apollo program. By 1963 funding for Dyna-Soar spaceplane had been cut leaving no practical use for Saturn I as DoD launcher. Most design variations were subsequently dropped with only S-V surviving in original form while S-IV appeared modified.
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Common questions
When did Wernher von Braun's team begin studying the Saturn I rocket?
Wernher von Braun's team at the U.S. Army Ballistic Missile Agency began studying a heavy-lift vehicle in April 1957.
What date was NASA formed and when did it select the Saturn I proposal?
NASA was formed on the 29th of July 1958 and selected von Braun's proposal for the Saturn I program on the 6th of January 1959.
How many engines powered the S-I first stage of the Saturn I rocket?
The S-I first stage was powered by eight H-1 rocket engines burning RP-1 fuel with liquid oxygen as oxidizer.
On what date did the Saturn I make its maiden flight?
The Saturn I made its maiden flight on the 27th of October 1961 with a dummy upper stage and partially fueled first stage.
Which launch marked the first time the Saturn I reached orbit?
SA-5 became the first Saturn I to reach orbit, achieving an altitude of 760 by 264 kilometers.