Category Apollo Saturn V News Reference

FIRST STAGE SYSTEMS Fuel System

The first stage fuel system supplies RP-1 fuel to the F-l engines. The system consists of a fuel tank, fuel feed lines, pressurization system, fill and drain components, fuel conditioning system, and asso­ciated hardware to meet the propulsion system requirements.

FUEL TANK

The fuel tank, previously described, holds 203,000 gallons of kerosene and is capable of providing 1,350 gallons of fuel per second to the engines through 10 fuel-suction lines.

FUEL FILL AND DRAIN SYSTEM

The fuel tank is filled through a 6-inch duct at the bottom of the tank. Fill rate is 200 gallons per min­ute until the tank is 10 per cent full. After reaching the 10 per cent mark, filling is increased to 2,000 gallons per minute until the tank is full. Normal nonemergency drain takes place through the same duct. A ball-type valve in the fill and drain line provides fuel shutoff.

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Fuel Fill and Drain

The fuel fill and drain system consists of a fill and drain line, a fill and drain valve, a fuel loading level probe, and nine temperature sensors. During fuel fill, the temperature sensors provide continuous fuel temperature information used to compute fuel density. When the fuel level in the fuel tank rises to about 102 per cent of flight requirements, the fuel loading probe indicates an overload.

After adjusting fuel to meet requirements, the fill and drain valve is closed.

The fuel tank can be drained under pressure by closing the fuel tank vent and relief valve, supply­ing a pressurizing gas to the tank through the fuel tank prepressurization system, and opening the fuel fill and drain valve.

TURBOPUMP

The turbopump is a direct-drive unit consisting of an oxidizer pump, a fuel pump, and a turbine mount­ed on a common shaft. The turbopump delivers fuel and oxidizer to the gas generator and the thrust chamber. LOX enters the turbopump axially through a single inlet in line with the shaft and is discharged tangentially through dual outlets. Fuel enters the turbopump radially through dual inlets and is dis­charged tangentially through dual outlets. The dual inlet and outlet design provides a balance of radial loads in the pump.

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Three bearing sets support the shaft. Matched tandem ball bearings, designated No. 1 and No. 2, provide shaft support between the oxidizer and fuel pumps. A roller bearing, No. 3. provides shaft support between the turbine wheel and the fuel pump. The bearings are cooled with fuel during pump operation. A heater block provides the outer support for No. 1 and No. 2 bearings, and is used during LOX chilldown of the oxidizer pump to pre­vent freezing of the bearings.

A gear ring installed on the shaft is used in con­junction with the torque gear housing for rotating

the pump shaft by hand, and also is used in con­junction with a magnetic transducer for monitoring shaft speed.

There are nine carbon seals in the turbopump: primary oxidizer seal, oxidizer intermediate seal, lube seal No. 1 bearing, lube seal No. 2 bearing, primary fuel seal, fuel inlet seal, fuel inlet oil seal, hot-gas secondary, and hot-gas primary seal.

The main shaft and the parts attaching directly to it are dynamically balanced prior to final assembly on the turbopump.

Second Stage Forward Skirt

exactness, and station locating is benefited by the even gravitational force exerted during each as­sembly operation. Constant checks and verification

of station planes and stage alignment are main­tained during each joining procedure by special scopes, levels, and traditional plumb bobs.

Another reason for vertical assembly involves the welding of cylinders and bulkhead. If the stage were welded while in a horizontal position, temperatnre diversion over the circumference could result in harmful expansion near the top of the stage.

To facilitate movement of the huge components and of the stage itself, a motorized transfer table rolls from outside to inside the building. Essentially, the assembly sequence begins with the welding of the lower two cylinders. Then the common bulkhead is welded to that assembly. Next the uppermost cyl­inder is welded to the LHa forward bulkhead. The aft LOX bulkhead and the aft facing sheet of the common bulkhead are welded together to form the liquid oxygen tank, and the thrust structure and aft skirt are then assembled to it. The remaining cylinders are then welded to the stage, and the for­ward skirt is then mated to the stage stack. The interstage is fit-checked to the thrust structure before interstage systems are installed. Throughout the assembly and welding operations, hydrostatic, X-ray, dye penetrant, and other tests and quality control devices are performed to ensure that speci­fications are met. The liquid hydrogen portion of the second stage as well as the liquid oxygen tank are given a thorough cleaning after assembly. After each bulkhead is welded to its components, it is hy­drostatically tested. After completion of stack weld operations, the entire stage is pneumostatically tested. After completion of these tests, the liquid

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Reposiiisring–Second stage is turned horizontally for checkout operation.

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Stage Complete…. Flight stage moves on transfer table from

assembly building to checkout building.

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Engine Installation—J-2 engines are mounted in stage.

After assembly, the stage Is moved to a vertical checkout building for final checks on all stage sys­tems.

STAGE SEPARATION SYSTEM

The stage separation system consists of a sever­able tension strap, mild detonating fuse (MDF), exploding bridgewire, (EBW), detonators and EBW firing units.

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Separation System

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Подпись: D-NRV-22 The severable tension strap houses two redundant MDF cords in a “V” groove circumventing the stage between the aft skirt and aft interstage at the sepa­ration plane. Ignition of the MDF cords is triggered by a signal from the second stage sequencer through the EBW and EBW firing units about 3 seconds after second stage engine cutoff.

The MDF consists of a flexible metal sheath sur­rounding a continuous core of high explosive mate­rial. Once detonated, the explosive force of the MDF occurs at a rate of 23,000 feet per second.

The EBW detonator is fired to initiate the MDF explosive train. A 2,300 VDC pulse is applied to a small resistance wire and a spark gap. The high voltage electrical arc across the spark gap ignites a charge of high explosive material which in turn detonates the MDF. The high voltage pulse require­ment for ignition renders this system safe from random ground or vehicle electrical power. Upon command, each EBW firing unit supplies high volt­age and current required to fire a specific EBW detonator.

FACILITIES

INTRODUCTION

Assembly, test, and launch facilities for the Saturn V consist of a combination of facilities which existed before the onset of the program as well as many specifically created for its execution.

Included in these facilities are installations set up by the National Aeronautics and Space Administra­tion to meet the greatly increased size and com­plexity of the Saturn program.

The Marshall Space Flight Center includes installa­tions at Huntsville, Ala., where vehicle develop­ment is the prime responsibility; Michaud Assembly Facility, New Orleans, La., where the first stage is fabricated and assembled; and Mississippi Test Facility. Bay St. Louis, Miss., which is responsible for test operations. Launch facilities are located at the NASA Kennedy Space Center, Fla.

Because of the giant size of Saturn launch vehicles and the difficulties in transporting them, fabrica­tion and test facilities were located within easy water shipment to the launch site.

At all of these NASA installations are located em­ployes of the companies which are the prime con­tractors for building the various stages and com­ponents of the Saturn V. Other facilities, including the home bases of the major contractors and sub­contractors, are located across the nation.

BOEING FACILITIES

The Boeing Company manufactures the Saturn V first stage at the 900-acre NASA Michoud Assembly Facility in New Orleans. The facility has about 2,000,000 square feet of manufacturing floor space and about 730,000 square feet of office space. About 60 per cent of the manufacturing area is occupied by Boeing.

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Michoud – The Michoud Assembly Facility is the fabrication site of the first stage booster. Dominating the skyline is the Vertical Assembly Building.

The plant is arranged for logical and efficient flow of materials from the loading dock through to final assembly. Paralleling the material flow are the rework and modification area and the test and laboratory areas. There are 50,000 square feet of tooling area in the plant.

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Stage Test—Before leaving Michoud, the completed booster undergoes a simulated firing during which all systems function in the Stage Test Building.

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Barge Slip—First stages are loaded onto barges at Michoud and travel by waterways from New Orleans to Huntsville, Mississippi Test Facility, and Kennedy Space Center.

The environmentally controlled portion of the minor

assembly area contains facilities for heat treat­ment, chemical cleaning, conversion coating, and welding of pre-formed metal sections received at the loading dock. Final assembly of the propellant tanks and the joining of the major components into the complete stage occur in the Vertical Assembly Building (VABI.

The VAB is a single-story structure rising the equivalent of 18 stories. A 180-ton overhead crane is used to stack the five large cylindrical segments of the first stage into a vertical assembly position. A $50 million program included the construction of three buildings—the VAB, the Stage Test Building,

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Checkout of the stage’s electrical and mechanical systems is performed in the four giant test cells of the Stage Test Building. Each of the test cells-is 83 by 191 feet with 51 feet of clear height. Each has

separate test and checkout equipment.

Stages leave and enter Miehoud by waterways

connecting to the Mississippi River or the Gulf of Mexico.

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Unique Vessels—Four of six special barges used to carry Saturn rocket stages are shown moored side-by-side at the Miehoud Assembly Facility. From left are the Little Lake, the Promise, the Poseidon, and the Palaemon.

NORTH AMERICAN SPACE DIVISION FACILITIES

The second stage of the Saturn V is manufactured and tested in facilities located from one end of the nation to the other.

The main fabrication and testing facilities are lo­cated in Seal Beach, Calif., about 15 miles south of Downey, which is the headquarters of SD opera­tions. SD subcontracts important elements of work to other North American facilities in Los Angeles and Tulsa and McAlester, Okla. The complex of buildings at Seal Beach, all built especially for the second stage, will be complemented by mid-1967 with three North American Aviation-owned build­ings which will house all the second stage admin­istrative, engineering, and support personnel who currently are located at Downey.

The Seal Beach facility includes a bulkhead fabri­cation building, 125-foot-high vertical assembly building, 116-foot-tall vertical checkout building, pneumatic test and packaging building, and a num­ber of other structures.

The bulkhead fabrication building is a large, highly specialized structure designed solely for the con­struction and assembly of the second stage’s three bulkheads. Among other tooling it contains an auto­clave about 40 feet in diameter with a 40-foot dome for curing the large stage bulkheads.

Over-all View—North American Sea! Beach facilities include in-process storage building (left); bulkhead fabrication building (center); vertical assembly building (far right); pneumatic test and packaging building (right center); and structural test tower (right front).

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Night firing of Test Second Stage at Santa Susana

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Space Truck Readied—The five engines of the Saturn V second stage dwarf technicians preparing the “battleship" vehicle for hot firing at North American’s Santa Susana static test lab.

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like conditions by being placed inside a 39-foot diameter vacuum chamber for extended periods of time. The chamber is capable of simulating the vacuum at an altitude of 500 miles above the earth. Structural tests on major vehicle structures such as the propellant tank, skirt sections, and interstage are conducted in the Structural Test Laboratory at the Space Systems Center.

Two vertical checkout towers at the Space Systems Center provide for the final factory tests on finished third stages, prior to shipment from the plant for test firing. The vertical checkout laboratory is equipped with two complete sets of automatic check­out equipment.

Actual ground test firings of the stages are accom­plished at the Douglas Sacramento Test Center, where each stage is delivered following the comple­tion of assembly and checkout at the Huntington Beach plant.

Primary Saturn facilities at Sacramento include a pair of 150-foot-high steel and concrete test stands where the stages are put through the final vehicle acceptance test—a full-duration, full-power static firing, simulating actual launch operations.

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Static Test Firing of Third Stage at Sacramento

The Super Guppy, the world’s largest airplane, is the primary means of transporting the third stage from the Douglas Huntington Beach plant to the Sacramento Test Center, and from Sacramento to KSC. Developed by Aero Spacelines, Inc., for trans­port of large space hardware, the plane has an inside diameter of 25 feet and a total length of 141 feet. Tail height is 46 feet—almost five stories above the ground. Cubic displacement of the fuse­lage is 49,790 cubic feet, approximately five times
that of most present jet transports. The airplane is powered by four turbo-prop engines, producing a total of 28,000 horsepower.

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Super Guppy

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FUEL FEED SYSTEM

Ten fuel suction lines (two per engine) supply fuel from the fuel tank to the five F-l engines. The suc­tion line outlets attach directly to the F-l engine fuel pump inlets.

Each suction line has a pneumatically controlled fuel prevalve which normally remains open. This

image37Подпись:Подпись:image38"FUEL-CONDITIONING (BUBBLING) SYSTEM

The fuel-conditioning system bubbles gaseous ni­trogen through the fuel feed lines and fuel tank to prevent fuel temperature stratification prior to launch. A wire mesh filter in the nitrogen supply line prevents discharge of contaminants into the conditioning system.

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Fuel Conditioning

A check valve in the outlet of each fuel-conditioning line prevents fuel from entering the nitrogen lines when the fuel-conditioning system is not operating.

An orifice located near each fuel-conditioning check valve provides the proper nitrogen flow into each fuel duct.

Oxidizer Pump

The oxidizer pump supplies oxidizer to the thrust chamber and gas generator at a flowrate of 24.811 gpm. The pump consists of an inlet, an inducer, an impeller, a volute, bearings, seals, and spacers. Oxidizer is introduced into the pump through the inlet which is connected by duct to the oxidizer tank. The inducer in the inlet increases the pressure of the oxidizer as it passes into the impeller to pre­vent cavitation. The impeller accelerates the oxi­dizer to the desired pressure and discharges it through diametrically opposed outlets into the high-pressure oxidizer lines leading to the thrust chamber and gas generator.

The oxidizer inlet, which attaches to a duct leading to the vehicle oxidizer tank, is bolted to the oxi­dizer volute. Two piston rings seated between the inlet and the volute expand and contract with tem­perature changes to maintain an effective seal between the high and low pressure sides of the inlet. Holes in the low-pressure side of the inlet allow leakage past the ring seals to flow into the suction side of the inducer, thus maintaining a low – pressure.

The oxidizer volute is secured to the fuel volute with pins and bolts which prevent rotational and axial movement. The primary oxidizer seal and spacer located in the oxidizer volute prevent fuel from leaking into the primary oxidizer seal drain cavity. The oxidizer intermediate seal directs a purge

Подпись:Fuel Pump

The fuel pump supplies fuel to the thrust chamber and gas generator at a flowrate of 15,471 gpm. The pump consists of an inlet, an inducer, an impeller, a volute, bearings, seals, and spacers. Fuel is intro­duced into the pump from the vehicle fuel tank through the inlet. The inducer in the inlet increases the pressure of the fuel as it passes into the impeller to prevent cavitation. The impeller accelerates the fuel to the desired pressure and discharges it through two diametrically opposed outlets into the high-pressure fuel lines leading to the thrust chamber and gas generator.

The fuel volute is bolted to the inlet and to a ring, which is pinned to the oxidizer volute. A wear-ring installed on the volute mates against the impeller. The cavity formed between the volute and the impeller is called the balance cavity. Pressure in the balance cavity exerts a downward force against the fuel impeller and counterbalances the upward force of the oxidizer impeller to control the amount of shaft axial force applied to the No. 1 and No. 2 bearings. Leakage between the impeller inlet and the discharge is controlled by a wear-ring, which mates with the impeller and acts as an orifice. The fuel volute provides support for the bearing retainer, which supports the No. 1 and No. 2 bearings and houses the bearing heater. The No. 3 seal, which is installed between the oxidizer intermediate seal and the No. 1 bearing, prevents lubricating fuel for the bearings from contacting the oxidizer. If fuel should pass the seal, purge flow from the oxidizer intermediate seal will expel the fuel overboard. On the fuel side of the No. 2 bearing, the No. 4 lube seal contains the lubricant within the bearing cavity. The remaining seal in the fuel volute is the primary seal and contains fuel under pressure in the balance cavity, maintains the desired balance cavity pres­sure, and keeps high-pressure fuel out of the low – pressure side.

PROPELLANT SYSTEM

The propellant system is composed of seven sub­systems : purge, fill and replenish, venting, pres­surization, propellant feed, recirculation, and pro­pellant management..

Purge Subsystem

The purge subsystem uses helium gas to clear the propellant tanks of contaminants before they are loaded. The important contaminants art* oxygen in the liquid hydrogen tank (liquid hydrogen will freeze oxygen which is impact-sensitive) and moisture in the liquid oxygen tank.

The tanks are purged with helium gas from ground storage tanks. The tanks are alternately pressur­ized and vented to dilute the concentration of con­taminants. The operation is repeated until samples of the helium gas emptied from the tanks show that contaminants have been removed or reduced to a safe level.

Fill and Replenish Subsystem

Filling of the propellant tanks on the second stage is a complex and precise task because of the nature of thd cryogenic liquids and the construction of the stage.

Because the metal of the stage is at normal outside temperature, it must be chilled gradually before pumping the ultra-cold propellants into the tanks. The filling operation thus starts with the introduc­tion of cold gas into the tanks, lines, valves, and other components that will come into contact with the cryogenic fluids. The cold gas is circulated until

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Channel Installed—Feed line from IH2 tank to one of the five engines is installed.

the metal has become chilled enough to begin pump­ing in the propellants. The filling and replenishing subsystem operation consists of five phases:

Chilldown – Propellants are first pumped into the tank at the rate of 500 gallons per minute for LQX and 1,000 gallons per minute for LHa. Despite the preliminary chilling by cold gas, the tanks are still so much warmer than the propellants that much of the latter boils off (converts to gaseous form) when it first goes into the tank. Filling con­tinues at this rate until enough of the propellants remain liquid so that the tanks are full to the five per cent level.

Fast Fill —As soon as tank sensors report that the liquid has reached the five per cent level, the fill­ing rate is increased to 5,000 gallons per minute for LOX and 10,000 gallons per minute for LH2. This rate continues until the liquid level in the tank reaches the 98 per cent level.

Slow-Fill—Propellant tanks are filled at the rate of 1,000 gallons per minute for both LOX and LH2 until the 100 per cent level is reached.

Replenishment—Because filling begins many hours before a scheduled liftoff and the cryogenic liquids are constantly boiling off, filling continues almost up to liftoff (160 seconds before liftoff for LOX and 70 seconds before liftoff for LH2). Tanks

are filled at the rate of up to 200 gallons per min­ute for LOX and up to 500 gallons per minute for LH,, depending on signals from sensors in the tanks on the liquid level.

101 Per Cent Shutdown—A sensor in each tank will send a signal to indicate that the 101 per cent level (over the proper fill level) has been reached; this signal causes immediate shutdown of filling operations.

Filling is accomplished through separate connec­tions, lines, and valves. The ground part of the con­nections is covered by special shrouds in which he­lium is circulated during filling operations. This provides an inert atmosphere around the coupling between the ground line and the tanks.

The coupling of the fill line and the tanks is engaged manually at the start of filling operations; it is nor­mally disengaged remotely by applying pneumatic pressure to the coupling lock and actuating a push – off mechanism. A backup method involves a remotely attached lanyard in which the vertical rise of the vehicle will unlock the coupling. The fill valves are designed so that loss of helium pressure or electrical power will automatically close them.

Liquid oxygen is the first propellant to be loaded onto the stage. It is pumped from ground storage tanks. Liquid hydrogen is transferred to the stage by pressurizing the ground storage tanks with gaseous hydrogen. The liquid hydrogen tank is chilled before the liquid oxygen is loaded to avoid structural stresses.

After filling is completed, the fill valves and the liquid oxygen debris valves in the coupling are closed, but the liquid hydrogen debris valve is left open. The liquid oxygen fill line is then drained and purged with helium. The liquid hydrogen line is purged up to the coupling. When a certain signal is received (first stage thrust-commit), the liquid hydrogen debris valve is closed and the coupling is separated from the stage.

The tanks can be drained by pressurizing them, opening the valves, and reversing the filling opera­tion.

RETROROCKET IGNITION SYSTEM

Four solid propellant retrorockets are mounted equidistant around the aft interstage assembly, and when ignited, assure clean separation of the third stage from the second stage by decelerating or braking the spent booster. Each retrorocket is rated for a nominal thrust of 35,000 pounds, weight of 384 pounds, and burn time of about 1.5 seconds.

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Retrorocket System

A signal from the second stage initiates two EBW firing units located on the aft interstage. The EBW firing units ignite two detonator manifolds, which in turn ignite the retrorockets through redundant pairs of confined detonating fuse (CDF) and py­rogen initiators.

Ullage Rocket System

ULLAGE CONTROL ROCKET IGNITION AND JETTISON SYSTEM

Two solid propellant ullage rockets, located on the third stage aft skirt just forward of the stage sepa­ration plane, are ignited on signal from the stage sequencer by EBW initiators.

After firing, the burned-out ullage rocket casings and fairings are jettisoned to reduce stage weight. Upon command from the stage sequencer, two forward and aft frangible nuts, which secure each rocket motor and its fairing to the stage, are det­onated by confined detonating fuse (CDF), to free the entire assembly from the vehicle.

IBM FACILITIES

Three IBM-owned buildings at Huntsville comprise the Space Systems Center where component test­ing, fabrication, assembly, and systems checkout of the instrument unit are completed. Assembly and the majority of the testing activity take place in a 130,000-square-foot building located in Hunts­ville’s Research Park.

As units are received, they are inspected and then moved to one of the testing laboratories where they are subjected to detailed quality and reliability testing. From component testing, the parts move

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Ш Assembly and Test—All instrument unit assembly work and the majority of testing are done in this IBM-owned building in Huntsville’s Research Park. The rear of the building is the high – bay area where assembly operations take place.

Подпись:Following assembly operations, the IU is moved to one of two systems checkout stands—one for uprated Saturn I vehicles, the other for Saturn V.

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Automatic Checkout-IBM technicians monitor systems checkout tests as another technician optically adjusts the inertial guidance platform, prior to a simulated mission.

A complete systems checkout is performed auto­matically. Hooked by underground cables, two digital checkout computer systems examine the IU. Each of the IU’s six subsystems is tested before the IU is tested as an integrated unit. With indepen­dent computers, systems tests for two instrument units can be conducted simultaneously.

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Simulation Laboratory Saturn V flight guidance and navigation programs as well as launch computer programs are tested in IBM’s Engineering Building at Huntsville. Here a technician checks a computer readout of a simulated mission.