|Space Launch Report . . . Saturn Vehicle History|
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NASA studied many Saturn booster concepts, but the agency only developed three during the 1960s. They were Saturn 1, Saturn 1B, and Saturn 5.
Cluster Booster Genesis
A November 1956 Department of Defense directive stripped the Army Ballistic Missile Agency (ABMA), at Redstone Arsenal near Huntsville, Alabama, of its prior mission to develop big ballistic missiles. General Medaris, ABMA commander, knew that his experienced rocket team would break up if not given a challenging assignment. The group, built around a core of more than 100 German emigrees who had worked at Peneemunde, was almost finished with engineering development of the Jupiter 1,500 mile range missile. Medaris and Wernher von Braun, director of the Development Operations Division, decided that ABMA would try to establish a new space launch mission for the U.S. Army.
First Saturn Launch, October 1961 (NASA) [Click for
In April 1957, von Braun directed H.H. Koelle, Chief of the Future Projects Design Branch, to study space launcher design options. Koelle evaluated designs for Jupiter-derived vehicles that could orbit small payloads, then began looking at big boosters that could put 20,000 pounds or more into low earth orbit. This would be enough to orbit humans, to put satellites into geosynchronous orbit, or to send small spacecraft to explore the moon. The big designs, built from clusters of existing or soon-to-exist missiles, were named "Super Atlas", "Super Titan", and "Super Jupiter". "Super Jupiter" received the most attention because it used hardware developed by ABMA. A cluster of four 370,000 pound thrust North American Aviation(NAA)/Rocketdyne E-1 engines powered the design. E-1 had been proposed by NAA, but not yet developed.
A variety of upper stage combinations were studied. Among these were a Jupiter-type second stage with a single E-1 engine and a third stage powered by an 80,000 pound thrust Atlas sustainer engine. Initially, "Super Jupiter" would use conventional kerosene/liquid oxygen (LOX) propellants, but Koelle recognized that substantial benefits could be realized by using high energy propellants, such as liquid hydrogen, in later third stage derivatives.
Koelle shelved the design drawings and didn't tell Von Braun about "Super Jupiter" for several months. The project came off the shelf after the Soviets orbited Sputnik in October. Von Braun was fully immersed in the designs by December, when he submitted his "Proposal for a National Integrated Missile and Space Vehicle Development Program" to the Department of Defense. It mentioned space launchers based on existing Redstone, Jupiter, and Atlas missiles. It also discussed Koelle's big cluster booster designs.
ABMA assigned the "Juno" name to its space rockets after the January 31, 1958 Explorer I success. The Jupiter-C satellite launcher became "Juno". A Jupiter missile with a Jupiter-C upper stage cluster became "Juno II". "Juno III" and "IV" were assigned to more powerful Jupiter derivatives that were proposed but not funded. Super Jupiter aquired the "Juno V" designation.
In February 1958, the Eisenhower administration created the Advanced Research Projects Agency (ARPA) to foster the development of space technology. ARPA was interested in Juno V from the outset. In July, two ARPA engineers, D.A. Young and R.B. Canright, visited ABMA. Reflecting ARPA's desire to develop a booster as quickly and cheaply as possible, they suggesting substituting eight existing Thor/Jupiter S-3D engines for the still-to-be-developed E-1. The change would save $60 million and two years in development time.
ABMA evaluated tank designs that could allow the booster to be airlifted in pieces to remote launch sites. A cluster of eight 70-inch diameter stretched Redstone-type tank sets, arranged to form a hollow cylinder, was considered. Each stretched Redstone fed a single engine from a top mounted refined kerosene (RP-1) tank and a bottom mounted LOX tank. Ultimately, ABMA settled on a more refined design that combined eight 70-inch diameter tanks, built using Redstone tooling, with a central 105-inch tank manufactured with Jupiter missile tooling. The central tank and four of the outer tanks would carry LOX and would be load bearing. The other four tanks would carry RP-1 fuel and would not carry structural loads because they would not expand and contract as much as the supercold LOX tanks. This design allowed each engine to access propellants from a pair of tanks, providing more robust engine-out capabilities.
The big cluster booster was officially born on August 17, 1958 when ARPA provided funding for a Juno V feasibility demonstration project. ABMA had expended 50,000 hours on the design prior to the award. The original plan called for construction of only one booster for captive firing tests on a modified Jupiter/Redstone test stand at the Arsenal. ABMA quickly contracted Rocketdyne to develop the first stage engine, now designated H-1. Early H-1 versions would be rated at 165,000 pounds thrust. Later models would produce 188,000 pounds of thrust.
When more funding became available at the start of the fiscal year in October, ARPA extended the effort to include four Juno V test flights for a total of $72 million. The first two suborbital flights would carry dummy upper stages and would test booster recovery techniques. Six large parachutes would lower the first stage to the ocean for recovery. Twelve retro rockets, triggered by a water-activated switch hanging below the booster on a 100 foot line, would fire just before impact to soften the blow. The booster would be floated onto an LSD and returned to the Cape.
The static test booster would be equipped with a new set of engines for the first flight. The latter two flights would use a Jupiter "interim" second stage to boost a payload to low earth orbit. Booster recovery would not be attempted on these flights due to the high staging velocity. The interim Jupiter second stage was quickly replaced by plans to launch a live third stage atop a dummy second stage.
Initial plans for a Juno V launch site at Cape Canaveral reflected the austere ARPA oversight. A mothballed Titan ICBM blockhouse at Launch Complex 20 would be used to control launches from a new launch pad just to the north. Eventually, funding was provided for a completely new site named Launch Complex 34. Construction began in mid 1959.
Von Braun's group began to informally call the booster "Saturn" during late 1958. ARPA officially adopted the name in February 1959.
While booster fabrication and test stand modifications commenced, Koelle's group worked on a "Saturn Systems Study" meant to pin down an upper stage combination for the new space booster. Completed in March 1959, the study contemplated a variety of "initial" or first-generation designs that used 120 inch diameter Atlas or Titan-derived second stages with one or two 200,000 pound thrust LOX/RP engines. A 160-inch diameter Titan-derived second stage, based on a Martin proposal for a four-engine "Titan C" booster for the U.S. Air Force Dyna Soar project, was also studied. ABMA like this stage because it provided better structural stability compared to the 120 inch diameter stages.
Saturn/Titan/Centaur compared to Juno I and Juno II
Third stage designs included a 120 inch diameter 80,000
pound thrust LOX/RP stage, a 6,000 pound thrust storable propellant stage, and a 30,000
pound thrust LOX/liquid hydrogen (LH2) Centaur stage.
Saturn First Generation Options Payloads 1st/2nd/3rd Stage 500 km LEO Escape Moon Landing Saturn/Atlas/Storable 21,100 lbs 2,400 lbs 0 lbs Saturn/Atlas/Centaur 30,900 lbs 9,200 lbs 1,300 lbs Saturn/Titan/Titan 19,100 lbs 480 lbs 0 lbs Saturn/Titan/Centaur 30,800 lbs 8,600 lbs 1,200 lbs
For a proposed second generation Saturn, Koelle embraced the use of liquid hydrogen fuel in all upper stages. The stages would use a new 225,000-250,000 pound thrust LOX/LH2 engine derived from the H-1 that Rocketdyne had proposed to ABMA. An all-new 256 inch diameter second stage would use two of the engines. Either Centaur or a new 160 inch diameter LOX/LH2 stage powered by a single large engine would top off the vehicle. The Saturn first stage itself would be upgraded to produce 2 million pounds of thrust, possibly through the addition of a single 1.5 million pound thrust F-1engine in place of the four center H-1 engines.
Saturn Second Generation Options Payloads 1st/2nd/3rd Stage 500 km LEO Escape Moon Landing Saturn*/Stg2*/Centaur 47,000 lbs 16,400 lbs 3,350 lbs Saturn*/Stg2*/Centaur/Stg4* 43,800 lbs 14,100 lbs 2,800 lbs Saturn*/Stg2*/Stg3*/Centaur 53,800 lbs 18,400 lbs 4,000 lbs *Saturn: 2 million pound thrust LOX/RP upgraded Saturn Stg2: 500,000 pound thrust LOX/LH2 256 inch diameter Stg3: 100,000 pound thrust LOX/LH2 160 inch diameter Stg4: 6,000 pound thrust storable
ABMA proposed a 16-flight development program for first generation Saturn that required the expenditure of $300 million through fiscal year 1961.
Beginning April 15, 1959, a joint ARPA/NASA/DoD "Saturn Ad Hoc Committee" reviewed the Saturn Systems Study. The committee recommended development of Saturn with a two-engine, 120-inch diameter Titan-derived second stage and a Centaur third stage. ARPA authorized the program on May 19.
This decision fixed the initial Saturn booster design, at least for the first few test launches. ABMA structural engineers began designing the stage to carry loads from a 120 inch diameter second stage.
From March to June of 1959, Koelle conducted a feasibility study for the U.S. Army Chief of R&D for a proposal to establishment a 12-man lunar outpost by 1966. The plan, a proposal to beat the Soviet's to the moon to prevent their "claiming" it before the 1967 50th anniversary of their government, was named Project Horizon.
ABMA proposed a Manhattan-Project-sized effort using Saturn I (the first generation version) and, in later years, a follow-on second generation Saturn II with all-new liquid hydrogen upper stages. Up to six Saturns would be placed into Earth orbit at a time. One would carry a lunar landing craft and an upper stage that would deplete its propellant during ascent but remain attached. The other five rockets would carry propellant to refuel the first vehicle. Other launches would have carried small cargo payloads on frequent direct flights to the moon or would have carried cargo and astronauts to a refueling station in earth orbit.
The plan called for as many as 66 Saturn launchings per year, or 5.5 per month, once the base became operational. The flights would have supported four major lunar landings via earth orbit rendezvous and 28 small payload landings via direct flight per year. Altogether, 229 Saturn flights were to occur by the end of 1967. To save money, Saturn boosters would be recovered and reused. Only 73 Saturn first stages would have been needed to perform the 229 missions.
Project Horizon would have cost $6 billion in 1959 dollars. It was not approved, of course, but the study showed that a moon landing was possible using technology that existed or soon would exist. The study showed that liquid hydrogen upper stages and a follow-on Saturn would be needed, that expendable lunar landing stages offered advantages, and that communications and guidance to lunar distances were possible. Project Horizon also highlighted the advantages of the Earth Orbit Rendezvous method.
Saturn/ABMA Transfer to NASA
ABMA began second stage contract discussions with Martin Corporation on July 24, but the entire Saturn project came to a sudden halt on July 29, when ARPA issued a stop order. The order originated from Herbert York, a Pentagon official who zeroed funding for the program. York believed that Saturn was too big and too expensive for Defense needs. He had been swayed by Martin's proposal for the ICBM-derived "Titan C", a rocket that would have been about half the size of Saturn. The issue had been muddled when ABMA, responding to an ARPA request, had said that Titan C would be a good upper stage combination for Saturn.
The stop order led to a critical program review during September by the ARPA/NASA Booster Evaluation (York/Dryden) Committee. ABMA tried to convince York that Martin had underestimated the cost of developing Titan C and that Saturn would be ready a year earlier than Titan C. York demanded that ABMA be transferred to NASA. Von Braun told York that his team would transfer only if Saturn survived. When the ABMA transfer was agreed upon, York restored temporary Saturn funding.
Saturn would be a joint ARPA/NASA program until the ABMA transfer was complete in early 1960. ABMA was renamed "George C. Marshall Space Flight Center" by the outgoing Eisenhower administration in honor of the President's World War II commander.
NASA and the Silverstein Committee
NASA, Saturn's new owner, asked for a new "Saturn Systems Study" to be performed based on its expected requirements for manned spaceflight and for deep space exploration. ABMA completed the study in November, 1959. Freed from the tight ARPA cost and schedule restraints, ABMA proposed an entirely new Saturn "B" series that fit between the existing Saturn/Titan/Centaur and second generation Saturn. The second generation Saturn with LH2 upper stages was now called "Saturn C".
Saturn B used a 220 inch diameter second stage powered by a cluster of four 200,000 pound thrust class LOX/RP engines and a 220 inch diameter third stage with four 20,000 pound thrust LOX/LH2 engines. Centaur could serve as an optional fourth stage. The recommended "B-1" design could put 35,000 pounds into LEO with three stages. With a fourth stage, B-1 could accelerate 11,200 pounds to escape velocity or land 4,000 pounds on the moon.
NASA organized a Saturn Vehicle Evaluation Committee (known as the Silverstein Committee) staffed by NASA, Defense, and former ABMA officials. Its participants included Dr. Abe Silverstein, chairman, of NASA and Dr. von Braun of ABMA. The committee first met in December 1959.
Von Braun recommended development of Saturn B-1 because its upper stages used existing engines. The use of existing propulsion for new rocket designs had long been a standard practice for von Braun. He reasoned that Saturn B-1 could start flying in 1962 while the more powerful 200,000 pound thrust LOX/LH2 engines needed for Saturn C would not be ready until 1965. He was not necessarily arguing against development of Saturn C at a later time.
Silverstein argued for skipping Saturn A-1 (as the Saturn/Titan design was now called) and Saturn B-1 altogether in favor of Saturn C. He showed that Saturn C could be developed in a step by step fashion. An interim Saturn C-1 model, equipped entirely with engines that already existed, could be developed several years before the big LOX/LH2 engines were ready. The C-1 second stage, called "S-IV", would use four 20,000 pound thrust Centaur-derived LOX/LH2 engines. An "S-V" third stage would be powered by two of the same engines. C-1 would be able to put 24,000 pounds into LEO with only two stages and 5,500 pounds into geosynchronous orbit with only three stages, one stage less than B-1.
Silverstein eventually swayed von Braun, allowing the committee to recommended that high-energy liquid hydrogen (LH2) engines power all of Saturn's upper stages and that a new 200,000-pound thrust LOX/LH2 engine, ultimately named J-2, be developed. The committee recommended that Saturn A and Saturn B not be developed.
Based on the Silverstein Committee findings, NASA announced plans in early 1960 to develop a series of three Saturn C boosters, assembled in building block fashion using a series of five stages.
Saturn C-1 would use the S-1 first stage to boost a new S-IV second stage and S-V third stage. Four 20,000 pound thrust LOX/LH2 engines would power S-IV. Two of the same engines would propel S-V, which would be Centaur-class, but not necessarily a Centaur stage. C-1 would start flying in 1961 and become operational in 1965. It would be used for earth orbital missions.
Saturn C-2 would include all of the C-1 stages with a new second stage, named S-III, inserted. S-III would be powered by two of the new J-2 engines. C-2 would enter flight testing in 1965. It would be used to orbit, supply, and send astronauts to a space station, to send astronauts around the Moon, and to boost solar system exploratory spacecraft.
Saturn C-3 would add a new S-II second stage to the S-I, S-III, and S-IV C-2 stages. S-II would use four J-2 engines. It would be used for advanced missions after 1970 including, possibly, manned lunar landings using the earth orbital rendezvous technique. S-1 would also be upgraded to 2 million pounds thrust for the C-3 rocket.
In April 1960, NASA contracted Douglas Aircraft Company to build the S-IV stage. Several months later, von Braun decided that the stage would be powered by six 15,000 pound thrust RL-10 engines, saving the time and cost of upgrading the engine to 20,000 pounds of thrust. Rocketdyne was contracted to build the J-2 engine.
In March 1960, NASA successfully test fired the first, non-flight Saturn static test stage (SA-T) in the modified static test tower at the Arsenal. Initial tests used one, then two, then progressively more H-1 engines in short burns. All eight H-1 motors fired together for the first time on April 29 in an 8-second test.
Static testing continued throughout the rest of the year. In the mean time, assembly work proceeded on the first Saturn flight stage (S-1-1) and on the construction of a dynamic test vehicle (SA-D).
MSFC assembled the stages in its own on-site main assembly building in a horizontal, rotating assembly fixture. The aft thrust structure would be lifted into the fixture first, followed by the central LOX tank and forward spider beam assembly. Then, the four outer LOX tanks would be lifted into place one at a time. The tanks were installed in opposing pairs to keep the jig balanced. Finally, the four black fuel tanks would be installed. The five LOX tanks were load-bearing. The fuel tanks were not.
During the final stages of assembly, a complex maze of propellant lines would be installed within the thrust structure. Some interconnected the tanks. Some connected to fill and drain valves. Others fed the engines. Each propellant tank, for example, fed fuel to one inboard and one outboard engine.
Finally, the eight H-1 engines would be installed. The four, fixed inboard engines were installed first, followed by the four, gimballed outboard engines. The last step was the installation of heat shield panels and aprons on the booster base. The completed stages were then rolled out on an eight-wheeled transporter cradle to the MSFC test stand.
Saturn Family Refined
In the spring of 1961, MSFC performed static testing of S-1-1, the first Saturn flight stage. That summer, the S-1-D dynamic test stage was mated with the first dummy S-IV and S-V stages for dynamic testing in Marshall's new vertical dynamic test tower, where the entire vehicle was subjected to flight-type vibrations.
As NASA refined its infant manned space exploration plans, the Saturn C-2 and C-3 designs changed. The proposed S-III stage disappeared from both rockets. Saturn C-2 now had an S-II second stage with four J-2 engines topped by an S-IV third stage and, when needed, an S-V fourth stage. C-2 would be able to put 45,000 pounds into low earth orbit and push 15,000 pounds to escape velocity. With three stages, C-2 would have stood 195 feet tall. With four stages, an Apollo capsule, and an emergency escape tower, the rocket would have stood 270 feet. Construction began on a new two-pad Cape Canaveral launch site, Complex 37, to support Saturn C-2.
MSFC totally shifted the C-3 design during 1961 until it consisted basically of a C-2 with a new first stage that was powered by two of the massive 1.5 million pound thrust F-1 engines then in development. C-3 would put 80,000 pounds in earth orbit and would push 30,000 pound payloads to escape velocity. A totally new launch site on Merritt Island, just northwest of the Cape, was being designed to handle C-3.
Saturn C-1 (Left) and C-2 Designs Circa 1960
C-2 - The Lost Saturn
In May 1961, President Kennedy dramatically altered the playing field with his decision to land men on the moon by 1970. NASA had to scrap its plans for a gradual build up toward a moon mission, and Saturn C-2 was the first victim. In July 1961, not long before the S-II contract was to be offered for bids, Von Braun shelved C-2 in favor of C-3. He took this action even though C-2 funding was fully authorized. Kennedy's timetable simply did not allow time for development of both C-2 and C-3.
C-2 might have been a versatile workhorse for NASA had it been developed. Today, the principal commercial launch vehicles; Ariane 4/5, Proton-K/DM, Zenit 3SL, Delta 4 and Atlas 5; mirror the C-2 specifications. Indeed, the Soviets originally developed Proton to perform space station and manned circumlunar missions, just like Saturn C-2. Three initial International Space Station modules were orbited by Proton boosters.
By November 1961, Von Braun's designers had abandoned the C-3, the S-IV and S-V stages, and the Silverstein building block concept altogether. An entirely new design, an unprecedented monster of a rocket named C-4, was envisioned. C-4 was designed specifically to perform Kennedy's moon landing mission.
C-4 had three entirely new stages. Four F-1 engines, totaling 6 million pounds of thrust, powered the first stage, which was called S-1B at the time. The enlarged S-II stage still had four J-2 engines, but a new S-IVB, now powered by a single J-2, would serve as the 250 foot-tall rocket's third stage.
In December 1961, NASA awarded the C-4 contracts. Boeing would build the S-1B stage at Michoud Assembly Facility in New Orleans. Douglas would build S-IVB stages at its Santa Monica plant. North American Aviation's existing S-II stage contract, awarded in September 1961 for the bypassed Saturn C-3 design, was modified for C-4. NAA would build S-II stages at its Seal Beach, California facility.
In January 1962, NASA added a fifth F-1 engine to the first stage and a fifth J-2 engine to the second stage. The modified design was named C-5. In June, 1962, MSFC announced that the S-IVB stage would be tested and flown first as a second stage atop an uprated Saturn C-1 first stage. The new rocket was named Saturn C-1B. The uprated first stage was designated S-1B. As a result, Boeing's C-5 first stage now became S-1C.
Saturn C-1 Flies
After a 10-day, 2,200 mile barge trip, the SA-1 first stage arrived at Cape Canaveral on August 15, 1961. At Complex 34, crews erected dummy S-IV and S-V stages, capped by a Jupiter missile nose cone, on top of the S-1-1 stage and an intense series of vehicle integration tests began.
At 10:06 AM EST on October 27, 1961, the 162 foot-tall, 927,000 pound rocket thundered from the pad on a nearly-perfect suborbital flight. SA-1 flew 215 miles downrange and reached an altitude of 85 miles along a 100 deg flight azimuth. Maximum velocity was 3,607 mph, achieved when the four outboard H-1 engines cut off 115 seconds after liftoff, about six seconds after the inboard engines shut down.
S-1-1 Erected at LC 34 (NASA)
SA-1, the heaviest object launched at the time, was a watershed event for NASA. Von Braun, Kurt Debus, and the flight team "went wild" in the Complex 34 blockhouse when the vehicle passed Max-Q. They had proved the cluster booster concept essential to achieve the moon landing goal.
By the time it flew, Saturn C-1 had already been made obsolete, C-2 had been abandoned, and MSFC had already begun thinking about shelving its Saturn C-3 designs. Even though Saturn C-1's S-IV stage would not fly for more than two years, MSFC was already planning to discontinue it in favor of S-IVB. Less than six months had passed since Kennedy's moon landing speech that wrought so much change.
MSFC performed the last of four suborbital Saturn C-1 Block 1 test flights on March 28, 1963.
Saturn C1 Block 1 Test Summary
Design: S-1 stages powered by 8x165,000 lb thrust Rocketdyne H-1 engines. No S-1 fins. Boattail tapered between 4 swiveling outboard engines. Dummy S-IV and S-V stages with water ballast and Jupiter nose cone. Guidance provided by ST-90 platform from Jupiter and ASC-15 computer from Titan, housed in canisters in adapter on top of S-1 stage.
SA-T: First Saturn C-1 booster stage used in extensive MSFC static tests beginning March 1960. Tested in configurations to mimic SA-1 through SA-5 through November 1962, then sent to Michoud for facility testing. Now on horizontal display next to static test tower at Marshall Space Flight Center.
SA-D: (S-1-D / S-IV-Dummy/S-V-Dummy). Block 1 dynamic test vehicle installed in new MSFC dynamic test stand for SA-D1 though SA-D4 tests between June 1961 and May 1962. Manufactured June 1960 - April 1961. Now on display at MSFC with dummy upper stages.
SA-1: (S-1-1/ S-IV-Dummy/S-V-Dummy). Launched 10/27/1961 on suborbital flight from Canaveral LC34. Manufactured May-December 1960. Trial horizontal assembly of complete vehicle at MSFC in February 1961. S-1-1 tested at MSFC static test tower March-May 1961. Shipped to Cape August 1961.
SA-2: (S-1-2/ S-IV-Dummy/S-V-Dummy) Launched 4/25/1962 on suborbital flight from Canaveral LC34. Upper stage water ballast released at T+162 sec (65 mi altititude) for Project Highwater. Manufactured December 1960-August 1961. S-1-2 tested at MSFC static test tower October-November 1961. Shipped to Cape February 1962.
SA-3: (S-1-3/ S-IV-Dummy/S-V-Dummy) Launched 11/16/1962 on suborbital flight from Canaveral LC34. Upper stage water ballast released for Project Highwater. Manufactured April-December 1961. S-1-3 tested at MSFC static test tower March-May 1962. Shipped to Cape September 1962.
SA-4: (S-1-4/S-IV-Dummy/S-V-Dummy) Launched 3/28/1963 on suborbital flight from Canaveral LC34. Performed successful inboard engine out demo at T+100 sec. Remaining engines burned 2 seconds longer to compensate, shutting down at T+114 sec (inboard) and T+121 sec (outboard). Manufactured July 1961-May 1962. S-1-4 tested at MSFC static test tower August-September 1962 (John F. Kennedy witnessed one test). Shipped to Cape February 1963.
Saturn 1 Block 2 - Testing the S-IV stage
By late 1962, Douglas had built four ground test versions of the new S-IV stage for NASA. The company delivered a hydrostatic/dynamic test version of the S-IV stage (S-IV-H/D) to MSFC. It manufactured a dynamic/facilities stage (S-IV-D/F) that would be shipped to Cape Canaveral to test the new Launch Complex 37. It completed and began test firing an S-IV-Battleship stage, built using heavier gauge stainless steel, at the company's Sacramento Test Operations (SACTO) facility. The flight weight S-IV-ASV (All Systems Vehicle) stage, built using flight weight aluminum tanks, would follow the Battleship to the test stands.
Douglas built S-IV in horizontal jigs at its Santa Monica facility, using techniques developed by the company for the Thor IRBM program. A milling process from Thor, for example, was used to cut a weight-trimming waffle pattern on the inner LH2 tank walls prior to tank welding. The tank walls were strong enough to bear weight whether the stage was pressurized or not.
The S-IV stage's six RL-10 engines were arranged in a hexagonal pattern. A truncated cone-shaped thrust structure transferred engine force to the propellant tank walls. Just above the engines was an elliptical LOX tank and above that was a cylindrical LH2 tank. A common bulkhead separated the two tanks. Six LH2 feed lines, one for each engine, wrapped around the outside of the LOX tank.
The S-IV-H/D stage was stacked atop the S-1-D5 dynamic test first stage, along with a dummy instrument unit and a dummy nose cone "payload", in MSFC's dynamic test stand in November 1962, forming the SA-D5 test vehicle. The S-IV-D/F stage was shipped to Cape Canaveral in January 1963, where, in April 1963 it was mated with the same S-1-D5 stage to check out Cape Canaveral's new Launch Complex 37B. After the tests were completed in June, both stages returned to MSFC for further testing. S-IV-D/F, delivered by a "Pregnant Guppy" modified B-377 aircraft, was used for propellant loading tests. S-1-D5 returned to the dynamic tower for more testing with the S-IV-H/D stage, this time with dummy Apollo "payload" hardware stacked on top to mimic the SA-6 flight vehicle.
The first flight S-IV stage (S-IV-5) was manufactured between January 1962 and April 1963. It was static fired at SACTO during August 1963. A planned 7 minute-duration test was stopped after 1 minute 36 seconds on August 5 when a test stand fire sensor incorrectly triggered, but the test was successfully completed on August 12. Douglas shipped the stage to the Cape in September.
Saturn 1 Operational Flights Cancelled
As of mid-1963, Douglas was contracted to build 12 flight S-IV stages. MSFC was building the last of its eight S-1 flight stages. Chrysler had won a contract to build two R&D and six operational S-1 stages at Michoud, along with 12 Saturn 1B first stages (S-1B-201 to 212). The R&D Saturn 1 stages, S-1-8 and S-1-10, were nearly complete.
Operational Saturn 1 flights would have tested flight-rated Apollo Command/Service Modules in low earth orbit. Four of these missions were to have been manned, beginning in 1965.
Six operational Saturn 1 vehicles, identified as SA-111 through SA-116, were on order until budget cutbacks and schedule pressure forced NASA to cancel the plan in October 1963, one month before Chrysler-Michoud was to begin final assembly of both the S-1-111 and S-1B-201 stages.
NASA transferred the four manned Apollo missions to the Saturn 1B program, which was now accelerated to follow an "all-up" testing philosophy wherein all launches, including the very first, would use all flight stages and would carry flight-rated Apollo command and service modules.
One reason mentioned for canceling Saturn 1 was that it would not be able to launch Apollo command/service modules (CSM) and Lunar Modules (LM) together, violating the new "all-up" philosophy. As it turned out, Saturn 1B was never used to launch CSM and LM at the same time.
Tanks had already been fabricated, but not assembled, for S-1-111. Presumably, these were diverted to the now-accelerated Saturn 1B program. Douglas saw its order for 12 S-IV flight stages halved. Some components that had already been manufactured for S-IV-111 and S-IV-112 had to be scrapped. The company's S-IVB contract quickly filled the void, however.
Prior to the 1963 cancellation, NASA planning called for parallel production of Saturn 1 and Saturn 1B vehicles until at least mid-1965. Some missions might have used S-1B first stages and S-IV second stages. LC34 was being modified to host the operational Saturn 1 missions during 1963. After the cancellation, LC34 was reassigned entirely to Saturn 1B. More modifications, required to support the S-IVB stage, were conducted during 1964 and 1965.
Block 2 Saturn 1 vehicles differed from their predecessors. The H-1 engines were uprated to 188,000 pound of thrust each, for a total of 1.5 million pounds. The S-1 aft thrust structure was simplified from a tapered boattail to a circular structure. Four large and four small fins were added for enhanced stability.
A new, 154 inch diameter, 18 inch tall Instrument Unit (IU) was added atop the S-IV stage. The IU, manufactured by MSFC, housed vehicle guidance, control, and telemetry systems. These included ST-90 and ST-124 guidance platforms.
The cancelled S-V dummy stage was no longer flown. Instead, a 154-inch diameter interstage was added to match the Apollo Service Module (SM) diameter.
NASA erected the first Block 2 S-1 stage, S-1-5, on LC 37B on August 23, 1963. A dummy spacer S-IV stage was added to support tests for several weeks. Then, on October 11, the first live S-IV stage was stacked. Later, the first IU, an SM interstage, and a modified Jupiter nose cone were attached to create the SA-5 launch vehicle.
SA-5's S-I/S-IV interstage sported a distinctive checkerboard roll pattern and the SM interstage and nose cone were painted jet-black.
Delays in S-IV testing, coupled with a pad fire during a November cryogenic tanking test and the discovery of cracked sleeves on pneumatic hydraulic line joints in the first stage delayed the SA-5 launch by several weeks. At the time, an informal "race" was underway between the Saturn crews at LC 37B and the Atlas Centaur crews at LC 36A to see which would be the first to successfully fly a liquid hydrogen upper stage. The first Centaur stage had not had a chance to fire its two RL-10 engines during the initial failed suborbital Atlas Centaur launch attempt in mid-1962. The second Centaur, AC-2, finally flew with success on November 27, 1963, but for awhile it looked like SA-5 might go first.
On January 24, 1964, the S-IV-ASV stage exploded shortly after an aborted static test fire countdown at SACTO. The test stage was destroyed, but no one was injured in the accident. A failed LOX vent valve combined with human error to create the accident.
Despite the ground test failure, SA-5 lifted off on January 29, 1964. After a clean first stage separation, the S-IV stage successfully ignited its six RL-10 engines. They burned for 479 seconds, pushing the stage, Saturn 1 instrument unit (IU), and a Jupiter nose cone into a 471 x 164 mile orbit inclined 31.5 degrees to the equator.
SA-6 and SA-7 also flew in 1964. On these missions, Saturn
1 carried and orbited Apollo boilerplate command modules topped with escape towers for the
first time. SA-6 survived an unexpected S-1 outboard engine (No. 8) shutdown at the T+116
second mark during its 5/8/1964 ascent. The remaining engines burned about two seconds
longer to compensate, with the inboards shutting down at T+142 seconds and the outboards
at T+148 seconds. The S-IV stage compensated for the early shutdown to enter a 124 x 140
mile x 31.5 degree orbit, close to the planned 110 x 140 mile orbit, proving beyond doubt
the robustness of the Saturn cluster booster design.
The last three Saturn 1 vehicles flew in 1965. In addition
to boilerplate command modules, SA-8, SA-9, and SA-10 orbited Pegasus micrometeoroid
detection experiment packages. These were attached above the IU, within the boilerplate
SM. On orbit, the Apollo boilerplate separated, allowing Pegasus to deploy a long detector
SA-8 used the first S-1 stage built by Chrysler-Michoud. A slight production delay caused it to fly after SA-9, which used the final MSFC-built S-1. When SA-10 flew in July 1965, preparations were already underway at adjacent LC34 for the first Saturn 1B launch. Not long after the LC 37B pad cooled, contractors also began swarming over that facility to prepare it for the new, uprated Saturn.
Saturn C1 Block 2 Test Summary
Design: S-1 powered by 8x188,000 lb thrust Rocketdyne H-1 engines. S-1 had four large fins, four smaller fins, and circular aft thrust structure. Live S-IV stage powered by 6x15,000 lb thrust Pratt & Whitney LOX/LH2 RL-10 engines. S-IV built by Douglas Aircraft.
S-I Test Stages:
S-I-D5: Block 2 dynamic test stage for SA-D5 dynamic vehicle testing in MSFC dynamic stand in November 1962. Used to checkout new LC 37B at Cape Canaveral March-May 1963. Returned to MSFC for more dynamic tests in late 1963. Later modified for use as a S-IB dynamic test stage. Now on display at US Space and Rocket Center, Huntsville, AL
S-IV Test Stages:
S-IV-Battleship: Battleship static test article with heavier gauge stainless steel tanks. Used for early tests of propellant and propulsion systems at Sacramento Test Operations (SACTO). Assembly completed mid 1962. Static testing began May 1962 at SACTO test stand 1. Presumed scrapped.
S-IV-ASV: Flight-weight "all systems" static test article with aluminum tanks. Used to test propellant and propulsion systems. Assembly July 1961-July 1962. Stood in SACTO test stand Alpha 2B for testing in February 1963. S-IV-ASV was destroyed in a static test accident at SACTO test stand Alpha 1 on 1-24-1964.
S-IV-H/D: Hydrostatic/Dynamic test stage. Reworked hydrostatic test stage completed for dynamic testing in October 1962. Used for dynamic testing in MSFC dynamic test tower from November 1962 to July 1964. Now on display at US Space and Rocket Center in Huntsville, AL.
S-IV-D/F: Dynamic/facilities test article used for facilities testing. Manufactured September 1961-May 1962. Used for facilities tests at Canaveral LC37B March-June 1963. Returned to MSFC for propellant testing in late 1963. Presumed scrapped.
SA-5: (S-1-5/ S-IV-5/S-IU-5) Launched 1/29/1964 from Canaveral LC37B on first S-IV/orbital mission to 471 x 164 mi x 31.5 deg orbit with Jupiter nose cone. S-I-5 assembly completed at MSFC 1/63. MSFC Static Test Stand 1/63 to 4/63. S-IV-5 Santa Monica, CA assembly completed 4/63. SACTO Alpha 2B Test Stand 5/63-9/63. S-I-5 and S-IU-5 delivered to Cape 8/63. S-IV-5 delivered Cape September 1963.
SA-6: (S-1-6/S-IV-6/S-IU-6) Launched 5/28/1964 from Canaveral LC37B with Apollo boilerplate BP-13 on orbital mission. Survived unexpected S-1 outboard engine No. 8 shutdown during ascent. S-I-6 MSFC assembly completed 1/63. MSFC Static Test Stand 4/63-6/63. S-IV-6 Santa Monica, CA assembly completed 7/63. SACTO Alpha 2B Test Stand 9/63-1/64. Stages delivered to Cape February 1964.
SA-7: (S-1-7/S-IV-7/S-IU-7) Launched 9/18/1964 from Canaveral LC37B with Apollo boilerplate BP-15 on orbital mission. S-I-7 MSFC assembly completed 5/63. MSFC Static Test Stand 9/63-11/63. S-IV-7 Santa Monica, CA assembly completed 10/63. SACTO Alpha 2B Test Stand 2/64-5/64. Stages delivered to Cape June 1964.
SA-9: (S-1-9/S-IV-9/S-IU-9) Launched 2/16/1965 from Canaveral LC37B with Apollo boilerplate BP-16 and Pegasus 1 meteoroid detection package on orbital mission. S-1-9 was last Saturn 1 stage built by MSFC. Vehicle launched out of order due slower delivery of S-1-8, first Chrysler-Michoud-built S-1 stage. S-I-9 MSFC assembly completed 9/63. MSFC Static Test Stand 2/64-4/64. S-IV-9 Santa Monica, CA assembly completed 2/64. SACTO Alpha 2B Test Stand 5/64-8/64. Stages delivered to Cape October 1964.
SA-8: (S-1-8/S-IV-8/S-IU-8) Launched 5/25/1965 from Canaveral LC37B with Apollo boilerplate BP-26 and Pegasus 2 meteoroid detection package on orbital mission. First Chrysler-Michoud-built S-1 stage. S-I-8 Michoud assembly completed 10/63. MSFC Static Test Stand 4/64-6/64. S-IV-8 Santa Monica, CA assembly completed 4/64. SACTO Alpha 2B Test Stand 8/64-12/64. Stages delivered to Cape February 1965.
SA-10: (S-1-10/S-IV-10/S-IU-10) Launched 7/30/1965 from Canaveral LC37B with Apollo boilerplate BP-9A and Pegasus 3 meteroid detection package on orbital mission. Second Chrysler-Michoud-built S-1 stage. S-I-10 Michoud assembly completed 3/64. MSFC Static Test Stand 7/64-10/64. S-IV-10 Santa Monica, CA assembly completed 8/64. SACTO Alpha 2B Test Stand 12/64-2/65.Stages delivered to Cape May 1965.
-End of Saturn 1 R&D program-
Juno V Space Vehicle Development Program Report No.
DSP-TM-10-58, October, 1958.
Last Update: May 8, 2009