Saturn V is the name of the space Fusée which was used by NASA for the programs Apollo and Skylab between 1967 and 1972, into full race with space between Americans and Soviets.

It was about a launcher on several floors, with Ergol S liquids, the last born of the family of Saturn launchers conceived under the direction of Wernher von Braun with the Center of space flight Marshall (MSFC) to Huntsville in Alabama, in collaboration with the companies Boeing, North American Aviation, Douglas Aircraft Company or IBM like principal contractors.

Saturn V remains still today the most powerful space launcher which was used in operation, that it is from the point of view height, mass on takeoff or mass of the Payload injected in orbit. Only the Russian rocket Energia, which flew only for two missions of test, slightly exceeded it on the level of thorough on takeoff.

Saturn V, which was conceived to launch the spaceship inhabited Apollo allowing the first steps of the man on the the Moon, continued its service while sending orbits the space station Skylab of it.

In all, NASA launched 13 rockets Saturn V, without having to deplore the least loss of Payload.

The three stages which composed Saturn V were developed by many companies sub-contracting under piloting of NASA. These companies, following multiple fusions and repurchases, do all today left the group Boeing.

Historical context

At the beginning of the Years 1960, the Soviet Union was very advances some on the the United States in the race with space. Indeed, in 1957, Soviet launched Sputnik 1, the first artificial satellite, and the April 12th 1961, the Russian Youri Gagarine became the first man sent orbits about it around the Earth.

The May 25th 1961, the president John Fitzgerald Kennedy announced that the United States was given like objective to send a man on the Moon before the end of the decade ( “We choose to go to the Moon” ). At that time, the only experiment that the United States of the manned flights had summarized at the 15 minutes of suborbital flight of Alan Shepard, at the time of the mission Mercury-Redstone 3 on board the capsule Freedom 7. No rocket of only one stage in the world could have sent a capsule inhabited on the Moon. The rocket Saturn I was under development, but had never yet taken off, and with its small size, one would have needed several launchings to place in orbit all the components of a lunar module.

At the beginning of the project, NASA studied three concepts different for the realization from the lunar mission: the concept known as of “go in terrestrial orbit” (EOR), that of the “direct rise” (or direct mode), and that of the “Rendez-vous in lunar orbit” (LOR - Lunar orbit go ). Although NASA drew aside at the beginning the idea of LOR, considering that an orbital rendezvous was already well rather complicated to realize in terrestrial orbit, it is finally this plan which was retained with the reasons of its total simplicity and speed with which it could be carried out, in optics to achieve the goal laid down by Kennedy.

One of the notable advantages of “concept LOR” was that, contrary to the concept of the direct rise, it did not require the use of a rocket of disproportionate size, like was the launcher Nova which was considered at the time ||2286 T |- | Moteurs' ||5 F-1 |- | Thorough ||33,4 MN |- | Operation life ||150 S |- | Propellents || RP-1 and LOX |- |colspan=" 2" align=center bgcolor=" #abcdef" | Second stage - software firm |- | Height ||24,8 meters |- | Diameter ||10 meters |- | Mass with propellents. ||464 T |- | Driving || 5 J-2 |- | Thorough ||5 MN |- | Operation life ||360 S |- | Propellents || LH2 and LOX |- |colspan=" 2" align=center bgcolor=" #abcdef" | Third stage - S-IVB |- | Height ||17,9 meters |- | Diameter ||6,6 meters |- | Mass with propellents. ||114 T |- | Driving ||1 J-2 |- | Thorough ||1 MN |- | Operation life ||165 + 335 s
(2 lightings) |- | Propellents || LH2 and LOX |}

Stage SIC

The stage SIC was built by the company Boeing with the center of assembly Michoud, with the New-Orleans, where is today built the tanks external of the American Space shuttle. As for the majority of the stages of a space rocket, almost the totality of the mass of 2.000 tons on the takeoff of SIC came from the fuel, in fact of the RP-1 and liquid oxygen.

This stage made 42 meters in height and 10 meters in diameter, and provided a push of 3.500 tons propelling the rocket during the first 61 kilometers of rise.

The 5 driving F-1 were laid out in cross. The central engine was fixed, while 4 outsides, assisted hydraulic actuating cylinders, could swivel to direct the rocket.

Stage software firm

The software firm was built by North American Aviation in Sea Beach in California. Using oxygen and hydrogen liquids, its 5 driving J-2 presented a provision similar to SIC. The second stage accelerated Saturn V through the high layers of the atmosphere thanks to a push of 5 MN. Completely charged, 97% of the mass of the stage came from the Ergol S

Sequences of launching for the lunar missions

The rocket Saturn V transported the astronauts of the Programme Apollo until the the Moon. All launchings took place since the complex of launching 39 with the space center John F. Kennedy. After the rocket had crossed the launching pads, the control of mission was transferred to the Johnson control center in Houston in Texas.

A standard mission used the rocket for a total of approximately twenty minutes. Although Apollo 6 and Apollo 13 knew engine failures, the trip computers were able to compensate while letting function the remaining engines longer, and none Apollo launchings finished a loss of the Payload.

Sequence of SIC

The first stage functioned during 2,5 minutes, hoisting the rocket at an altitude of 61 km with a speed of 8.600 km/h after having burned 2.000 T of propellents.

To 8,9 S before launching, the sequence of lighting of the 1st stage started. The central engine ignited in first, followed by the two pairs of symmetrical engines with a 300 ms shift to reduce the mechanical efforts on the rocket. Once the attack of the maximum push was confirmed by the trip computers, the rocket “was slackened carefully” in two stages: the arms which maintained the rocket unbolted to release it then, whereas the launcher started to accelerate vertically, from the metal fixings hung through slits in the rocket became deformed gradually until slackening the launcher completely. This last operation lasted a half second. As from this moment, no flashback was possible; if an engine had an operating fault, the rocket could not be any more recovered on the launching pad.

It took approximately 12 seconds for the rocket to move away from the tower of launching. Once it had exceeded it, it carried out a movement of swivelling to move away suitably from the zone of shooting, to prevent the cases of head winds or engine failure.

At an altitude of 130 meters, the rocket started to take Roulis and to rock to have the good Azimut. Launching until second 38 after the lighting of the second stage, Saturn V used a program preregistered for the instruction of the angle of plate. The instruction took account of the dominant winds generally measured during the month corresponding to launching.

By precaution, the four peripheral engines were tilted towards outside, so that if an engine had suddenly stopped, the push of the remaining engines is directed towards the center of gravity of the rocket. Saturn V accelerated quickly, reaching the speed of 500 m/s to 2 km of altitude. The priority of the preliminary phase of the flight was to gain altitude, the later coming criterion speed.

After approximately 80 seconds, the rocket reached the point of maximum, known dynamic pressure under the name of max Q . The dynamic pressure on a rocket is proportional to the density of the air around the rocket and the square speed. Although the speed of the rocket increases with altitude, the density of the air, it, decrease.

At 135,5 seconds, the central engine died out to reduce the structural constraints on the rocket due to acceleration. This operation was imposed by the fact that the rocket became lighter progressively of the consumption of propellents. There were no means simpler to arrive at this result, since the push of the driving F-1 was not controllable. 600 milliseconds after the extinction of the engine, the first stage separated with the assistance from eight small solid propellent motors. Just before the first stage is not released, the crew underwent his stronger acceleration, 4 G (either 39 m/s ²). This occurred at an altitude approximately 62 km.

After separation, the first stage continued its trajectory until an altitude of 110 km. Indeed, the peripheral engines continued to function until the sensors in the systems of aspirations do not measure the exhaustion of one of two propellents. Then the first stage fell down in the Atlantic Ocean to approximately 560 km of the launching pad.

Sequence of the software firm

After the sequence of operation of SIC, stage software firm took over and, in 6 minutes, propelled the rocket at an altitude of 185 km and a speed of: 24600 km/h, value close the orbital velocity.

The second stage followed a procedure of lighting in two times, which varied during various launchings of Saturn V. For the first two uninhabited missions of the rocket, the first time consisted of lighting during 4 seconds of eight engines of ullaging to powder, in order to réaccélérer the launcher. Then the 5 J-2 engines returned under operation. For the first seven inhabited Apollo missions, only four engines of ullage were used. For last four launchings of Saturn, the four unutilised engines were even withdrawn.

The second time of the procedure consisted of the separation of the skirt inter-stage, approximately 30 seconds after the dropping of the first stage. This operation of separation asked for a great detail, because it was not necessary that the inter-stage does not touch the engines, knowing that it passed to only one meter them. At the same time that the inter-stage separated, the system of rescue was released. This system was envisaged in the event of failure of the rocket during the phase of launching.

Approximately 38 seconds after the lighting of the second stage, the guidance system of Saturn V passed from an instruction preregistered for the attitude to a guidance system in loop, controlled by the instruments of the equipment box, such as accelerometers and measuring instrument of altitude. If the trip computers took along the rocket out of the limits of the acceptable trajectories, the crew could either cancel the mission or of taking the control of the launcher by using one of the rotary handles of piloting located in the capsule.

Approximately 90 seconds before the separation of the second stage, the central engine died out to reduce the known longitudinal oscillations under the name of “pogo”. A system of elimination of the pogo effect was set up starting from Apollo 14, but the central engine was always extinct in advance. About at the same time, the flow of LOX decreased, modifying the ratio of mixture of two propellents, and ensuring that there remained as little of propellents as possible in the tanks at the end of the sequence of flight of the second stage. This operation was carried out for a certain value of ΔV.

There were five sensors at the bottom of each tank of the software firm. Once two of them were discovered, the control systems of Saturn V initiated the sequence of change of stage. One second after the extinction of the second stage, this last separated and a tenth of a second later the third stage ignited. Retrorockets with powder assembled on the inter-stage at the top of the second stage were started to help the second empty stage to move away from the remainder of the launcher. Stage software firm fell down approximately to 4.200 km of the site of launching.

Sequence of the S-IVB

The third stage functioned during the 2,5 following minutes.

Contrary to the preceding separation of stages, there was no specific operation of separation for the inter-stage. The inter-stage between the second and third stages remained attached on the second floor (although it was built like a component of the third stage).

10 minutes and 30 seconds after takeoff, Saturn V was to 164 km of altitude and 1.700 away km on the ground of the site of launching. A few moments later, after operations of placing in orbit, the launcher was on an terrestrial orbit of 180 km out of 165 km. They was low enough for an terrestrial orbit and the trajectory would not have remained stable because of frictions with the high layers of the atmosphere. For the two missions of placing in terrestrial orbit, Apollo 9 and Skylab, the orbit of injection was higher.

Once on this orbit known as “carpark”, the S-IVB and the spaceship, remained attached, produced two turns and half around the Earth while the astronauts examined the vessel and the remainder of the rocket to make sure that all was in perfect operating condition and to prepare the vessel for the operation of injection “translunaire” (TLI).

Operation TLI intervened approximately 2 hours and half after launching, when the third stage was re-ignited to propel the spaceship towards the the Moon. The second operation of the S-IVB lasted 6 minutes leading the vessel at an high speed with 10 km/s, sufficient to escape from the attraction of the Earth.

A few hours after operation TLI, the module of order and service Apollo (CSM) separated from the third stage, swivelled of 180 degrees, then fastened with the Lunar module (LEM) which was located under the CSM during the phase of launching. To finish, the CSM and the LEM were detached from the third stage.

If it had remained on the same trajectory as the Apollo vessel, the third stage could have presented a danger to the continuation of the mission. To avoid that, the remaining propellents in the tanks were evacuated engine, which changed its trajectory. Starting from Apollo 13, the controllers directed the third stage towards the Moon. Seismographs deposited on the Moon by preceding missions detected the impacts, and the recorded data contributed to study the interior composition of the Moon. Before Apollo 13 (except Apollo 9 and Apollo 12), the third stages were placed on a trajectory passing near the the Moon which returned them towards a solar orbit. Apollo 9 as for him was directed directly towards a solar orbit.

Stage S-IVB of Apollo 12 knew a very different destiny. The September 3rd 2002, Bill Yeung discovered a suspect asteroid to which it gave the provisional name of J002E3. It proved to be in orbit around the Earth, and it was quickly discovered by spectral analysis that it was covered with titanium a white dioxide painting, the same one as that used for Saturn V. the controllers of mission had envisaged to send the S-IVB of Apollo 12 in solar orbit but driving lighting after the separation of the Apollo vessel lasted too a long time and the third stage passed too much close to the Moon and finishes on a hardly stable orbit around the Earth and the Moon. It is thought that in 1971, following a series of gravitational disturbances, the S-IVB was placed on a solar orbit then reconsidered an terrestrial orbit 31 years later. In June 2003, this third stage left the terrestrial orbit.

Mission Skylab

In 1968, the application program Apollo was created in order to study the scientific expeditions which could be realized with the surplus of equipment of the Apollo program. Most of the reflections turned around the idea of a space station, which gave rise to finally the program Skylab. The launching of Skylab, calling upon Saturn INT-21, a launcher on two floors derived from Saturn V, was the only launching of Saturn V not directly related to the Apollo program of first man on the Moon.

In the beginning, it was envisaged to follow the concept known as of the “wet” workshop, with a stage of rocket used for launching in orbit, then, once empties, reconverted in space station by the installations carried out in orbit. But this concept was abandoned with the profit of the concept of the “dry” workshop: a stage S-IVB of the launcher Saturn 1B transformed on the ground into the space station Skylab then launched by Saturn V. a system of replacement, which was built starting from a third stage of Saturn V, is exposed today to the National Air and Space Museum.

Three crews occupied Skylab May 25th 1973 until the February 8th 1974. Skylab remained in orbit until in May 1979.

One hoped in the beginning that Skylab would remain sufficiently a long time orbits about it to be visited by the American Space shuttle during its very first flights. The shuttle could have gone up the orbit of Skylab, and have enabled him to be used as a base for future space stations. However, the shuttle did not fly before 1981 and, retrospectively, aware was become that Skylab would in any event not have been of a great utility, not being conceived to be restocked or supplied.

Developments suggested for after Apollo

The second crop year of Saturn V, which was cancelled, would have doubtless used engines F-1A on the first stage, providing a substantial surplus of push. Other probable changes would have been the removal of the wings (which proved to bring little benefit have regard to their weight); a first stages SIC stretched to support more powerful engines F-1A; and of the J-2 engines improved for the upper floors.

A certain number of alternatives of Saturn launchers based on Saturn V were proposed, active of Saturn INT-20 with a stage S-IVB and a inter-stage assembled directly on the stage SIC, in Saturn V-23 (L) which would have not only had 5 F-1 engines on the first stage, but also 4 booster rockets added with each one 2 F-1 engines, increasing the full number of F-1 engines under operation with launching with 13!

The American Space shuttle was initially conceived like a transport system to use in.liaison.with Saturn V, so much so that was imagined a “Saturn Shuttle” which, using the current orbiteurs and tanks external, but with these tanks assembled on a version modified of SIC and flying on its back, would have been used to propel the shuttle lasting the first two minutes of flight, after which SIC would have been released and would be turned over towards the Space center Kennedy for restocking, and the principal engines of the space shuttle would have been started to place the orbitor in orbit. The shuttle was to deal with the logistics of the space station, while Saturn V was to deal with the launching of the various components. The absence of the second series of production of Saturn V ruined this plan and left the United States without superheavy launcher. Some within the American space community strongly regretted this situation, knowing that the continuation of the production would have allowed the realization of the International space station, in configuration Skylab or Mir with the ports of Russian and American anchorings, with a handle only of launchings. Some also consider that the concept of “Saturn shuttle” would have made it possible to avoid the conditions which brought to the disaster of Challenger in 1986.

Saturn V would have been the launcher of the space probes Voyager towards Mars which were cancelled, and would have being the launcher used for the program RIFT of test of stage with nuclear propulsion and for the program NERVA.

Successors with Saturn V

To the United States, the proposals for a rocket larger than Saturn V studied of the end of the year 1950 until beginning of the year 1980 carried all the general name of Nova. One counts thus more than thirty proposals different from large rocket with this name.

Wernher von Braun and others had also plans for a rocket which would have had eight driving F-1 on its first stage enabling him to send a spaceship manned directly towards the Moon. Other alternatives for Saturn V suggested using Centaur like upper floor or adding auxiliary booster rockets. These improvements would have increased its capacity to send large uninhabited vessels to explore another planets or vessels manned towards Mars.

Currently, in 2007, NASA envisages to build the superheavy launcher Ares V, a derivative of the space shuttle. Ares V will have about the same height and the same mass that Saturn V. This new launcher was baptized in the honor of Saturn V. It is intended to be an uninhabited vehicle, with strong capacity of launching, is planned for the future live missions towards the Moon and possibly later towards Mars.

Contrary to Saturn V which has three stages, Ares V will be on two floors, with a principal stage 10 meters in diameter (the same one as on the stages SIC and software firm) propelled by hydrogen and oxygen liquid and assisted during its first two minutes of flight by a pair of booster rockets with powder derived from those of the American Space shuttle, with 5 powder segments instead of 4 currently. The principal stage will be been driven by five engines of rocket RS-68 with the same provision as that used on the stages SIC and software firm. In the beginning Ares V was to use 5 engines SMI (driving principal of the American space shuttle), but the swing towards the RS-68 was justified by an aspect cost, and the fact that these engines functioned successfully on the system of uninhabited launching Delta IV EELV. Moreover, the RS-68 are more powerful and easier to manufacture than the SMI.

Engines RS-68, built by division Rocketdyne of Pratt & Whitney (before property of Boeing and international Rockwell) are more effective than the driving F-1 of Saturn V. On the other hand, the driving J-2 used on the software firm and the S-IVB will be modified and become improved engines J-2X to be gone up on the stage starting of the Earth (Earth Departure Stage - EDS), the second stage of Ares V derived from the S-IVB, and on the second stage of the rocket in proposal Ares 1. Stage EDS and the second stage of Ares 1 should use only one engine J-2X, although initially the EDS was envisaged with 2 engines until the change of design replacing the 5 SMI by 5 RS-68.

Cost

Of 1964 with 1973, a total of 6,5 billion dollars was spent for Saturn V. It is in 1966 that the annual financial effort was most important with a sum of 1,2 billion dollars

One of the main reasons to the stop of the Programme Apollo was its cost. In 1966, NASA accepted its most important budget, 4,5 billion dollars, about 0,5% of the GDP of the United States at the time. The same year, the Department of Defense of the United States received 63,5 billion dollars.

Various launchings of Saturn V

Today

Today, there are three Saturn V which is exposed, all with the horizontal one:

• With the space center Johnson, one can see Saturn V made up of the first stage of the SA-514, the second stage of the SA-515 and third stage of the SA-513

• With the Space center Kennedy, it is made up of the S-IC-T (stage of test) and of the second and third stage of the SA-514

• In the American center of space and the rockets, it is made up of the S-IC-D, S-II-F/D and of the S-IVB-D (all the stages of test not planned for a real flight)

On these three Saturn V, only that of the Johnson space center is entirely made up of stages planned for a real launching. The American center of space and the rockets with Huntsville also has in exposure of a counterpart on the scale Saturn V set up to the vertical. The first stage of the SA-515 is with the center of assembly Michoud in Louisiana. The third stage of the SA-515 as for him was converted to be used as replacement for Skylab. This last is today visible with the American national museum of the air and space.

A rumor spread since 1996, claims that NASA lost or destroyed the plans of Saturn V. In fact, the plans always exist with the Center of space flight Marshall, preserved on microfilms.

Appendices

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