Laminated Honeycomb Sandwich
Figure 7-2
Attached to the inner surface of the cylinder are cold plates which serve both as mounting structure and thermal conditioning units for the electrical/electronic equipment. Mounting the electrical/electronic equipment around the inner circumference of the IU leaves the center of the unit open to accommodate the convex upper tank bulkhead of the S-1VB stage and the landing gear of the Lunar Excursion Module (LEM).
Cross section "A" of figure 7-3 shows equipment mounting pads bolted and bonded to the honeycomb structure. This method is used when equipment is not mounted on thermal conditioning cold plates. The bolts are inserted through the honeycomb core, and the bolt ends and nuts protrude through the outside surface. Cross section"B" shows a thermal conditioning cold plate mounting panel bolted to brackets which, in turn, are bolted on the honeycomb structure. The bolts go through the honeycomb core with the bolt heads protruding through the outer surface. Cross section "C" shows the cable tray supports bolted to inserts, which are potted in the honeycomb core at the upper and lower edges of the structure.
Figure 7-4 shows the relative locations of all equipment installed in the IU.
environmental control system f
The environmental control system (ECS) maintains an acceptable operating environment for the IU equipment during preflight and flight operations. The ECS is composed of the following:
1. The thermal conditioning system (TCS) which maintains a circulating coolant temperature to the electronic equipment of 59 (± 1) degrees F.
2. The preflight purging system which maintains a supply of temperature and pressure regulated air/GN2 in the IU/S-IVB equipment area.
3. The gas-bearing supply system which furnishes GN2 to the ST-124-M3 inertial platform gas bearings.
4. The hazardous gas detection sampling equipment which monitors the IU/S-IVB forward interstage area for the presence of hazardous vapors.
THERMAL CONDITIONING SYSTEM
Thermal conditioning panels, also called cold plates, are located in both the IU and S-IVB stage; there are up to sixteen in each. Each cold plate contains tapped bolt holes in a grid pattern which provides flexibility of component mounting.
The cooling fluid circulated through the TCS is a mixture of C 60% methanol and 40% demineralized water, by weight. Each cold plate is capable of dissipating at least 420 watts.
A functional flow diagram is shown in figure 7-5. The main coolant loop is the methanol-water mixture. Two heat exchangers are employed in the system. One is used during the preflight mode and employs a GSE supplied, circulating, methanol-water solution as the heat exchanging medium. The other is the flight mode unit, and it employs demineralized water and the principle of sublimation to effect the cooling.
The manifold, plumbing, and both accumulators are manually filled during the prelaunch preparations. The accumulators serve as dampers to absorb pressure fluctuations and thermal expansion, and also as reservoirs to replace lost or expended fluids. There are flexible diaphragms in each accumulator, backed by low pressure GN2.
During operation of the TCS, the methanol-water coolant is circulated through a closed loop by electrically driven, redundant pumps. The flow is from the heat exchanger past the accumulator, through the pumps, through a temperature sensor to an orifice assembly. The orifice assembly diverts part of the coolant to the cold plates in the S-IVB stage and part to the cold plates, gas bearing heat exchanger, inertial platform, LVDC/LVDA and flight control computer in the IU. Return flow is through a modulating flow control assembly which regulates the amount of coolant flowing into the heat exchangers or around them. Operation of this valve is based on fluid temperature. V
Figure 7-2
EQUIPMENT MOUNTING PADS
COLD PLATE
HORIZONTAL SPLICE PLATE
INNER SPLICE PLATE
OUTER SPLICE PLATE
TYPICAL SPLICE PLATE ATTACHMENT
HORIZONTAL SPLICE PLATE
INNER SPLICE PLATE
OUTER SPLICE PLATE
CABLE TRAY
SUPPORTS
CABLE TRAY
SUPPORTS
- SLA INTERFACE
•UPPER MOUNTING RING
0.95 IN. FULL WALL THICKNESS
-HIGH DENSITY CORE
LOW DENSITY CORE
-0.030 ALUM 7075-T6 OUTER SKIN
-0.020 ALUM ALLOY 7075-T6 INNER SKir
-LOWER MOUNTING RING
S-IVB INTERFACE TYPICAL SECTIONAL VIEW
During the preflight mode, the subliinator heat exchanger is inactive due to the high ambient pressure (one atmosphere), and a solenoid valve which blocks the water flow. The preflight heat exchanger is operated from the GSH, and cools the closed loop fluid.
Approximately 180 seconds after liftoff, the water solenoid valve is opened and the sublimator heat exchanger becomes active. During the period between GSE disconnect and sublimator activation, the residual cooling in the system is sufficient to preclude equipment overheating.
The sublimator element is a porous plate. Since the sublimator is not activated until approximately 180 seconds after launch, the ambient temperature and pressure outside the porous plates are quite low. Water flows readily into the porous plates and attempts to flow through the pores. However, the water freezes when it meets the low temperature of the space environment, and the resulting ice blocks the pores (see figure 7-6).
As heat is generated by equipment, the temperature in the methanol-water solution rrises. This heat is transferred within the sublimator to the demineralized water. As the water temperature rises, it causes the ice in the pores to sublime. The vapor is vented overboard. As the heat flow decreases, ice plugs are formed in the pores, decreasing the water flow. Thus, the sublimator is a self-regulating system. GN2 for the methanol-water and water accumulators is stored in a 165 cubic inch sphere in the IU, at a pressure of 3,000 psig. The sphere is filled by applying high pressure GN2 through the umbilical. A solenoid valve controls the flow into the sphere, and a pressure transducer indicates to the GSE when the sphere is pressurized. The output of the sphere is applied to the accumulators through a filter and a pressure regulator.
which reduces the 3,000 psig to 15 psia. An orifice regulator further reduces the pressure at the accumulator to 5 psia, the differential of 10 psia being vented into the IU.
PREFLIGHT AIR/GN2 PURGE SYSTEM
The preflight air/GN2 purge system (see figure 7-7) consists primarily of flexible ducting located above the IU payioad interface. The system distributes ground supplied, temperature and pressure regulated, filtered air or GN2 through openings in the ducting. During preflight phases, ventilating air is furnished. During fueling, inert GN2 is furnished to prevent accumulation of a hazardous and corrosive atmosphere.
GAS BEARING SUPPLY
Gaseous nitrogen, for the ST-124-M3 stable platform, is stored in a two cubic foot sphere in the IU, at a pressure of 3,000 psig (see figure 7-5). The sphere is filled by applying high pressure GN2 through the umbilical, under control of the IU pneumatic console. A low pressure switch monitors the sphere and, if the pressure falls below 1,000 psig, the ST-124-M3 stable platform is shut down to preclude damage to the gas bearing.
Output of the sphere is through a filter and a pressure regulator. The regulator reduces the sphere pressure to a level suitable for gas bearing lubrication. Pressure at the gas bearing is sampled and applied, as a control pressure to the regulator. This provides for a constant pressure across the gas bearing. From the main regulator, the gas flows through a heat exchanger where its temperature is stabilized, then through another filter and on to the gas bearing. Spent gas is then vented into the IU.
INSTRUMENT UNIT EQUIPMENT LOCATIONS
INSTRUMENT UNIT EQUIPMENT LOCATIONS
AUXILIARY POWER DISTRIBUTOR
— MEASURING RACK
FLEX TUBING ASSY (ENVIRONMENTAL CONTROL DUCTS'
CABLE TRAY
SOURCE FOLLOWER
MEASURING RACK
POWER
DISTRIBUTOR
CCS COAXIAL SWITCH
BATTERY
BATTERY
AUXILIARY POWER DISTRIBUTOR
— MEASURING RACK
POWER
DISTRIBUTOR
BATTERY
BATTERY
CCS COAXIAL SWITCH
CCS POWER AMPLIFIER
UHF RF ASSY
CCS TRANSPONDER
UHF COAXIAL SWITCH
WATER
ACCUMULATOR ASSY
D40 BATTERY
TELEMETRY POWER DIVIDER
COAXIAL TERMINATION
CCS POWER AMPLIFIER
UHF RF ASSY
CCS TRANSPONDER
UHF COAXIAL SWITCH
WATER
ACCUMULATOR ASSY
D40 BATTERY
TELEMETRY POWER DIVIDER
COAXIAL SWITCH
COAXIAL TERMINATION
SLOW-SPEED
MULTIPLEXER
ASSY
- METHANOL-WATER ACCUMULATOR
PRESSURE SWITCH
AND TRANSDUCER
COOLANT PUMP ASSY
165 CUBIC INCH SPHERE
COOLANT PUMP ASSY
HEAT
EXCHANGER ASSY'S
GN2 FILL AND VENT VALVE
■MODULATING FLOW CONTROL VALVE
PRESSURE SWITCH
AND TRANSDUCER
COOLANT PUMP ASSY
165 CUBIC INCH SPHERE
COOLANT PUMP ASSY
HEAT
EXCHANGER ASSY'S
GN2 FILL AND VENT VALVE
■MODULATING FLOW CONTROL VALVE
MEASURING DISTRIBUTOR
POS II
PI MULTIPLEXER ASSY
TAPE RECORDER —
MEASURING DISTRIBUTOR
POS II
PI MULTIPLEXER ASSY
TAPE RECORDER —
SLOW-SPEED
MULTIPLEXER
ASSY
MEASURING RACK
F2 RF ASSY
MEASURING ASSY VSWR
F2 TELEMETRY ASSY
SI TELEMETRY ASSY
MEASURING RACK
AUXILIARY POWER
DISTRIBUTOR
THERMAL PROBE
F2 MULTIPLEXER ASSEMBLY
TELEMETRY RF COUPLER
F2 RF ASSY
MEASURING ASSY VSWR
F2 TELEMETRY ASSY
SI TELEMETRY ASSY
FI RF ASSEMBLY
MEASURING DISTRIBUTOR-
MEASURING RACK-
FI RF ASSEMBLY
MEASURING DISTRIBUTOR-
MEASURING RACK-
DISTRIBUTOR
THERMAL PROBE
C-BAND
TRANSPONDER NO. 2
MASTER MEASURING VOLTAGE SUPPLY
FI TELEMETRY ASSY
L- MEASURING RACK
TELEMETRY
CALIBRATION
DISTRIBUTOR
THERMAL PROBE
MEASURING RACK
C-BAND
TRANSPONDER NO. 2
MASTER MEASURING VOLTAGE SUPPLY
FI TELEMETRY ASSY
L- MEASURING RACK
TELEMETRY CALIBRATION POWER AND CONTROL ASSY
TELEMETRY
CALIBRATION
ASSY pos HI
MEASURING RACK'
REMOTE DIGITAL MULTIPLEXER MODEL 410 (J)
SWITCH SELECTOR MODEL 2
ENGINE CUTOFF ENABLE TIMER
CCS POWER DIVIDER
CCS HYBRID RING
ASSY pos HI
MEASURING RACK'
REMOTE DIGITAL MULTIPLEXER MODEL 410 (J)
SWITCH SELECTOR MODEL 2
ENGINE CUTOFF ENABLE TIMER
CONTROL SIGNAL PROCESSOR
MEASURING RACK
FLIGHT
CONTROL
COMPUTER
CONTROL EDS RATE GYRO
BATTERY STRIP HEATERS
CONTROL SIGNAL PROCESSOR
MEASURING RACK
FLIGHT
CONTROL
COMPUTER
CONTROL EDS RATE GYRO
BATTERY STRIP HEATERS
ACCELEROMETER SIGNAL CONDITIONER
CONTROL DISTRIBUTOR
REMOTE DIGITAL MULTIPLEXER MODEL 410
IU COMMAND DECODER
LAUNCH VEHICLE DATA ADAPTER
LAUNCH VEHICLE DIGITAL COMPUTER
■PLATFORM AC POWER SUPPLY
POS IV
ST-l24-M3
ELECTRONIC
ASSY
THERMAL PROBE
ACCELEROMETER SIGNAL CONDITIONER
C-BAND TRANSPONDER
BATTERY STRIP HEATER
CONTROL DISTRIBUTOR
REMOTE DIGITAL MULTIPLEXER MODEL 410
IU COMMAND DECODER
LAUNCH VEHICLE DATA ADAPTER
LAUNCH VEHICLE DIGITAL COMPUTER
■PLATFORM AC POWER SUPPLY
GAS BEARING HEAT
EXCHANGER
ST-l24-M3
PLATFORM
ASSY
GN2 1000 PSI SWITCH GN2 BEARING SUPPLY (2 CU. FT.)
POS IV
GAS BEARING SOLENOID VALVE i
GAS BEARING PRESSURE REGULATOR
ACCELEROMETER ASSY
GAS BEARING HEAT
EXCHANGER
ST-l24-M3
PLATFORM
ASSY
GN2 1000 PSI SWITCH GN2 BEARING SUPPLY (2 CU. FT.)
ORIFICE ASSEMBLY -1111111111111111 i[JjrT
GN2 SUPPLY & IjECt EMERGENCY VENT!
LEGEND
II 1111II METHANOL-WATER COOLANT
METHANOL-WATER (GSE SUPPLIED) GASEOUS NITROGEN ^GN2)
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LEGEND
II 1111II METHANOL-WATER COOLANT
METHANOL-WATER (GSE SUPPLIED) GASEOUS NITROGEN ^GN2)
I II 111
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KKKXX WATER AND WATER VAPOR I I CALIBRATE LINE (REMOVED PRIOR TO FLIGHT)
I 11111 m 111111 Mtt^' 11111 mTTnm£xn^S' 111111£ 11111 n F njjmï
RETURN
FACILITIES AVAILABLE FOR 16 COLD PLATES
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