The Saturn series of launch vehicles are large-scale rockets developed for NASA's Apollo lunar landing program. This type of rocket was originally proposed by Wernher Von Braun in 1957, who at that time was assigned to the Army Ballistic Missile Agency (ABMA). Following its establishment in 1958, Von Braun and other U.S. Army scientists were transferred to NASA, with the Saturn rocket development program subsequently becoming a NASA endeavor.
The Saturn IB launch vehicle was conceived in 1962 at the NASA Marshall Space Flight Center as the quickest, most reliable, and most economical means of providing a booster with greater payload capability than the Saturn I. The new launch vehicle would be used for earth orbital missions with the Apollo spacecraft before the Saturn V lunar launch vehicle would be available.
The initially developed Saturn I adopted cluster of 8 engines essentially the same as used in the Jupiter rocket. Test firing of the Saturn I began in 1961. From 1966, the Saturn IB was developed, incorporating the hydrogen fuel J-2 engine for the rocket second stage. Saturn IB, including the spacecraft and tower, stands approximately 224 feet tall, and is about 21.7 feet in diameter. Total weight empty is about 85 tons, and liftoff weight fully fueled, will be approximately 650 tons. First-stage flight is powered by eight H-1 engines generating 200,000 pounds of thrust each, for a total of 1.6 million pounds. In approximately 2.5 minutes of operation, it will burn 41,000 gallons of RP-1 fuel and 66,000 gallons of liquid oxygen, to reach an altitude of approximately 42 miles at burnout. H-1 engines for later S-IB vehicles will be uprated to 205,000 pounds of thrust each.
SA-201 lifted off from SLC34 on 2/26/1966. NASA called the successful 39 minute suborbital mission Apollo-Saturn (AS) 201. The S-IVB J-2 engine and the Apollo Service Module engine both worked well on this, their first flight. Saturn accelerated Apollo to 29,000 kilometers per hour, pushing it to a 488 km apogee. The CM splashed down 8,472 km downrange, east of Ascension Island. Problems with CSM-011 delayed the next planned Saturn 1B mission, which used booster SA-202, so SA-203 was launch first. SA-203, flying the AS-203 mission, was an extended orbital test of the S-IVB stage. An aerodynamic shroud topped off the SLA in place of a CSM.
Crews stacked SA-203 on refurbished LC37B beginning in April. By June, SA-203 was joined by SA-202, standing on nearby LC34, and, several miles to the north, SA-500F, the Saturn V facilities checkout vehicle, standing on LC39A. SA-203 lifted off on July 5 and performed a perfect four-orbit mission in a 185 x 189 km orbit. The AS-202 mission, another successful suborbital flight, finally took place on August 25. This time, the CSM apogee was 1,143 km and the spacecraft nearly completed one orbit before it splashed down in the Pacific Ocean.
NASA declared Apollo-Saturn 1B ready for manned flight. At LC34, SA-204 was prepared for the first manned Apollo mission, which was to be called AS-204. CSM-012 was stacked and tested. On January 27, 1967, however, a flash fire in the capsule during the final countdown demonstration test killed astronauts Grissom, White, and Chaffee.
The disaster halted Apollo manned flights for 21 months and stunted the Saturn 1B program. The SA-204 vehicle was destacked, stored, and, eventually, restacked on LC37B, where it stood for months waiting for delayed LM-1. The rocket did not fly until January 22, 1968, when it carryed LM-1 into orbit beneath another aerodynamically-shrouded SLA on the Apollo 5 mission. SA-204 injected LM-1 into an initial 222 x 163 km orbit. The LM descent engine fired for the first time, followed by the ascent engine. After the ascent burn, LM-1 was left in a 961 x 172 km orbit. The entire mission was complete after four orbits.
SA-205 finally carried the first manned Apollo 7 mission aloft from LC34 on 10/11/1968. Onlookers did not know at the time that SA-205 would be the last Saturn I launched from Cape Canaveral. The rocket boosted CSM-101 into a 140 x 183 mi orbit. Astronauts Walter Schirra, Don Eisele, and Walter Cunningham orbited the earth in Apollo 7 163 times during a 10 day 20 hour mission before landing near Bermuda in the Atlantic.
The Saturn IB version was also used to launch the manned Skylab 2,3 and 4 missions in 1972 and 73, and for the Apollo-Soyuz Program carried out jointly with the Soviet Union in 1975. The most famous of the Saturn Missiles is the Saturn V, that launched man to the moon.
When the United States made the decision in 1961 to undertake a manned lunar landing effort as the focal point of a broad new space exploration program. there was no rocket in the country even approaching the needed capability. There was a sort of "test bed" in the making, a multi-engine vehicle now known as Saturn I. It had never flown. And it was much too small to offer any real hope of sending a trio to the moon, except possibly through as many as a half dozen separate launchings from earth and the perfection of rendezvous and docking techniques, which had never been tried.
That was the situation that brought about the announcement on Jan. 10, 1962, that the National Aeronautics and Space Administration would develop a new rocket, much larger than any previously attempted. It would be based on the F-1 rocket engine. the development of which had been underway since 1958. and the hydrogen-fueled J-2 engine, upon which work had begun in 1960.
The Saturn V then, is the first large vehicle in the U.S. space program to be conceived and developed for a specific purpose. The lunar landing task dictated the make-up of the vehicle, but it was not developed solely for that mission. As President Kennedy pointed out when he issued his space challenge to the Congress on May 25, 1961, the overall objective is for "this Nation to take a clearly leading role in space achievement which in many ways may hold the key to our future on earth." He said of the lunar landing project: "No single space project in this period will be more exciting. or more impressive to mankind, or more important for the long-range exploration of space; and none will be so difficult or expensive to accomplish... "
The Saturn V program is the biggest rocket effort undertaken in this country. Its total cost, including the production of 15 vehicles between now and early 1970 will be above $7 billion.
NASA formally assigned the task of developing the Saturn V to the Marshall Space Flight Center on Jan. 25, 1962. Launch responsibility was committed to the Kennedy Space Center. (The Manned Spacecraft Center, the third center in manned space flight, is responsible for spacecraft development, crew training, and inflight control.)
Marshall Center rocket designers conceived the Saturn V in 1961 and early 1960. They decided that a three-stage vehicle would best serve the immediate needs for a lunar landing mission and would serve well as a general purpose space exploration vehicle.
One of the more important decisions made early in the program called for the fullest possible use of components and techniques proven in the Saturn I program. As a result, the Saturn V third stage (S- IVB) was patterned after the Saturn I second stage (S-IV). And the Saturn V instrument unit is an outgrowth of the one used on Saturn I. In these areas, maximum use of designs and facilities already available was incorporated to save time and costs.
Many other components were necessary, including altogether new first and second stages (S-IC and S- II). The F-1 and J-2 engines were already under development, although much work remained to be done. The guidance system was to be an improvement on that of the Saturn I.
The Rocketdyne H-1 engine was the workhorse of the early Apollo-Saturn program. The Saturn 1 and Saturn 1B rockets used eight of these capable engines in the first stage booster. The first Apollo astronauts roared into space atop an H-1 powered Saturn 1B, as did all the Skylab mission crews. The 205,000 lb thrust H-1 is a fixed-thrust, single-start gimbaled engine that employs a propellant system of RP-1 (kerosene) and liquid oxygen. Advances include a turbopump with a one-piece gearbox and fuel additive lubrication, a solid propellant gas generator for start-up, propellant valve sequencing, and hypergolic start-up in the thrust chamber.
The Rocketdyne J-2 engine may be the most important engine in the development history of manned space flight propulsion. The J-2 was the first manned booster engine that used liquid hydrogen as a propellant. The J-2 was also the first large booster engine designed to be restarted multiple times during a mission. The J-2 engine was so versatile that it was used for both the second and third stages of the Saturn V moon rocket. And a modified J-2 engine was used to demonstrate principles that lead to the development of Rocketdyne's Space Shuttle Main Engine. The 230,000 lb thrust J-2 features independantly driven pumps for both liquid oxygen and liquid hydrogen, a gas generator to supply hot gas to two turbines running in series, pneumatic and electrical control interlocks, altitude restart capability, and a propellant utilization system.
The Mighty F-1 was perhaps Rocketdyne's greatest contribution to the American space program. Just one F-1 engine provided as much thrust as all three Space Shuttle Main Engines! Even more amazing is that a cluster of five F-1 engines were used in the first stage of the 363-foot tall Saturn V rocket. A single-start, fixed-thrust engine, the F-1 is gimbaled and uses liquid oxygen as the oxidizer, while RP-1 (kerosene) is used as the fuel, the turbopump lubricant, and the control system fluid. A gas generator utilizing the same propellants drives the turbine, which is direct-coupled to the turbopump.
The Saturn V, including the Apollo spacecraft. is 364 feet tall. Fully loaded, the vehicle will weigh some 6.1 million pounds.
The 300,000-pound first stage is 33 feet in diameter and 138 feet long. It is powered by five F-1 engines generating 7.5 million pounds thrust. The booster will burn 203,000 gallons of RP-1 (refined kerosene) and 331,000 gallons of liquid oxygen (LOX} in 2.5 minutes.
Saturn V's second stage is powered by five J-2 engines that generate a total thrust of a million pounds. The 33-foot diameter stage weighs 95,000 pounds empty and more than a million pounds loaded. It burns some 260,000 gallons of liquid hydrogen and 83,000 gallons of liquid oxygen during a typical 6- minute flight.
Third stage of the vehicle is 21 feet and 8 inches in diameter and 58 feet and 7 inches long. An interstage adapter connects the larger diameter second stage to the smaller upper stage. Empty weight Off the stage is 34,000 pounds and the fueled weight is 262,000 pounds. A single J-2 engine developing up to 225,000 pounds of thrust powers the stage. Typical burn time is 2.75 minutes for the first burn and 5.2 minutes to a translunar injection.
The vehicle instrument unit sits atop the third stage. The unit, which weighs some 4,500 pounds. contains the electronic gear that controls engine ignition and cutoff, steering, and all other commands necessary for the Saturn V mission. Diameter of the instrument unit is 21 feet and 8 inches, and height is 3 feet.
Directly above the instrument unit in the Apollo configuration is the Apollo spacecraft. It consists of the lunar module. the service module, the command module, and the launch escape system. Total height of the package is about 80 feet.
The jumping-off place for a trip to the moon is NASA's Launch Complex 39 at the Kennedy Space Center. After the propellants are loaded, the three astronauts will enter the spacecraft and check out their equipment.
While the astronauts tick off the last minutes of the countdown in the command module, a large crew in the launch control center handles the complicated launch operations. For the last two minutes, the countdown is fully automatic.
At the end of countdown, the five F-1 engines in the first stage ignite, producing 7.5 million pounds of thrust. The holddown arms release the vehicle, and three astronauts begin their ride to the moon.
Turbopumps, working together with the strength of 30 diesel locomotives, force 15 tons of fuel per second into the engines. Steadily increasing acceleration pushes the astronauts back into their couches as the rocket generates 4-5 times the force of earth gravity.
After 2.5 minutes, the first stage has burned its 4,492,000 pounds of propellants and is discarded at about 38 miles altitude. The second stage's five J-2 engines are ignited. Speed at this moment is 5,330 miles per hour.
The second stage's five J-2 engines burn for about 6 minutes, pushing the Apollo spacecraft to an altitude of nearly 115 miles and near orbital velocity of 15,300 miles per hour. After burnout the second stage drops away and retrorockets slow it for its fall into the Atlantic Ocean west of Africa.
The single J-2 engine in the third stage now ignites and burns for 2.75 minutes. This brief burn boosts the spacecraft to orbital velocity, about 1,500 miles an hour. The spacecraft, with the third stage still attached, goes into orbit about 12 minutes after liftoff. Propellants in the third stage are not depleted when the engine is shut down. This stage stays with the spacecraft in earth orbit. for its engine will be needed again.
Throughout the launch phase of the mission, telemetry systems are transmitting continously, tracking systems are locked on, and voice communications are used to keep in touch with the astronauts. All stage separations and engine thrust terminations are reported to the Mission Control Center at Houston.
The astronauts are now in a weightless condition as they circle the earth in a "parking orbit" until the timing is right for the next step to the moon.
The first attempt at a lunar landing is planned as an "open-ended" mission with detailed plans at every stage for mission termination if necessary. A comprehensive set of alternate flight plans will be laid out and fuller rehearsed for use if such a decision should prove necessary. For example, a decision might be made in the earth parking orbit not to continue with the mission. At ever: stage of the mission, right up to touchdown on the moon, this termination decision can be made and an earth flight plan initiated.
During the one to three times the spacecraft circles the earth, the astronauts make a complete check of the third stage and the spacecraft. Then the precise moment comes for injection into a translunar trajectory, the third stage J- 2 engine is reignited. Burning slightly over 5 minutes, it accelerates the spacecraft from its earth orbital speed of 17,500 miles an hour to about 24,500 miles an hour in a trajectory which could carry the astronauts around the moon. Without further thrust. the spacecraft would return to earth for re-entry.
If everything is operating on schedule, the astronauts will turn their spacecraft around and dock with the lunar landing module. After the docking maneuver has been completed. the lunar module will be pulled out of the forward end of the third stage which will be abandoned. Abandonment completes the Saturn V's work on the lunar mission.