The Command Module is the most complex piece of hardware in the entire stack.
The Command Module has a double structure, comprised of the cabin and the outer wall. For heat shielding, the outer wall is made of stainless steel brazed honeycomb between steel alloy face sheets. It protects the inside of the ship from the heat of the sun and the heat from atmospheric friction during re-entry. The thickness of this outer wall varies from 0.5-inch (1.27cm) to 2.5-inch (6.35cm). The cabin is built with a honeycomb structure of aluminum mated with an aluminum alloy. The thickness of the wall of this tin can varies from 0.25-inch (6.35mm) to 1.5-inch (3.81cm). Insulating fiber is placed between the outer wall and the cabin. Phenolic, a synthetic material made by applying heat and pressure to layers of paper or glass cloth impregnated with synthetic resin, coats the surface of the Command Module. It shields the CM from frictional heat by melting during re-entry. The thickness of this coating is 0.5-inch (1.27cm) all around, except for the bottom, which is 2-inch (5.08cm). This brings the CM's weight to 3000lb (1362kg). Thermal coating made of silver Mylar is applied on top of this. This gives the CM the appearance of being wrapped in aluminum foil, giving the CM it's reflective look. The cockpit is divided into three parts. The docking tunnel is the forward compartment. The crew compartment is the area in which the astronauts spend their time. Finally, there is an aft compartment in the back of the CM. The forward compartment is separated by a bulkhead from the cabin, and is divided into 4 areas at ninety-degree angles. Earth landing equipment like parachutes and beacon lights are stored here. This area is covered with the forward shield cover, which is installed under the LES legs. This cover is jettisoned with when the CM is at approximately 25,000 feet after re-entry, preparing for the deployment of the parachute. The cabin is filled with pure oxygen at about 1/3 sea-level atmospheric pressure, and a temperature of 21-24 degrees Celsius (70-75 Fahrenheit). The astronaut's seating follows traditional seating in an airplane. The left seat is for the Commander (CDR), the center seat is for the CM Pilot (CMP), and the right seat is for the LM pilot (LMP). These gcouches are made of steel framing and tubing and covered with a heavy, fireproof fiberglass cloth. There is room for two people to stand when the center couch is folded down. Two sleeping bags are installed behind the left and right seats, and two astronauts at a time can sleep. Each seat is supported by eight struts, which compress to absorb the shock when the spacecraft splashes down. Mirrors to confirm the installation of the harness when an astronaut dons his spacesuit are attached to each seat.
Materials such as water and food are packed and stored in the wall on the side of the cabin. After launch, the astronauts remove their spacesuits, and wear overalls in the cabin. The astronauts normally only wear their spacesuits during launch, LM docking and undocking, moving between CM and LM, EVA, and re-entry. The commander usually handles the operation of the ship, while the CMP does navigation, and the LMP monitors and operates the sub-systems. While the CDR and LMP are on the surface of the moon, the CMP handles observation of the surface and serves as a communications relay between the Earth and LM, in addition to the normal work of the CDR and LMP. Of course, all three astronauts are trained in all systems and procedures, so that in the event of an emergency, even a single person can still safely return to the Earth.
Two nitrogen gas bottles and cylinders are installed into the cabin's hatch. When an emergency occurs during launch, one of the bottles is used for explosively opening the hatch. After a normal launch, the contents of this bottle are vented into space. The other bottle is used for explosively opening the hatch after splashdown. The hatch also has a valve that can vent the cabin atmosphere in one minute. The cabin has five windows, made of 0.25-inch (6.35mm) double-paned tempered glass on the inside, and 0.7-inch (1.778cm) amorphous-fused silicon on the outside. UV-ray blocking coating is applied in these outer surfaces, and non-reflective coating to the inside. The outer glass can stand up to a maximum temperature of about 1540 degrees Celsius (2800 Fahrenheit). A covering shield made of aluminum is installed inside all of the windows. A mirror to confirm the deployment of the parachutes during re-entry is installed over and under the right rendezvous window. The aft compartment is just inside of the bottom heat shield, and it is divided into 24 parts. There are 10 RCS (reaction control subsystem) rocket engines, fuel, oxygen, a helium tank, water, and many other materials. The outer walls of this compartment are removable for pre-launch maintenance. Many important materials are stored in the lower equipment bay, underneath the astronauts' feet, such as the navigation station, guidance and navigation electronic equipment, sextant to determine position in space, the telescope, a computer and keyboard (DSKY), batteries, and the communication system. Food and science observation materials are stored in compartments here. The main materials of the environmental control subsystem are stored in the left bay. This also is where the hatch is stored after the CSM and LM dock. The waste management system controls and equipment, electrical power equipment, and other electronics are stored in the right bay. Some of the food is stored here, too. Bays behind the astronauts are where the spacesuits and helmets are stored. Life vests, the fecal canister, portable life support systems (PLSS backpacks), and other equipment are stored here. The probe and drogue assembly used for docking with the LM is stored here as well.
The Service Module supported the Command Module
The Service Module (SM) is connected to the Command Module (CM) until just before re-entry, and it supplies oxygen, water and electric power to the Command Module. The SM is equipped with the SPS (Service Propulsion Subsystem) engine, four quads of four (16 elements) RCS (Reaction Control Subsystem) engines, the fuel, oxidizer, helium which is necessary for these. These engines are used to control the flight path until CM/SM separation just before re-entry. The SPS engine and its fuel accounts for about 75% of the weight of the SM. The SM body is made of aluminum honeycomb core between two aluminum face sheets, with a thickness of about one inch. The "spine" of the SM is made of a 44-inch (1.11m) diameter cylinder installed in the center of the SM, with 6 sections (Sector 1 to Sector 6) surrounding it. The 360 degrees around this center section is divided among two 50-degree sections (Sectors 1 and 4), two 60-degree sections (Sectors 3 and 6), and two 70-degree sections (Sectors 2 and 5). Center SectionTwo 40-inch diameter globular helium tanks and the SPS engine are located here. Each helium tank carries 19.6 cubic feet of helium gas, pressurized at 3600psi. These are used to "pump" fuel and oxygen for the SPS engine. The fuel is "pumped" to the engine from the tanks by injecting this inert gas. Sector 1A weight to help balance the SM was carried in this sector from Apollo 1 through Apollo 14. For Apollo 15 through 17, this was used as the SIM (Scientific Instrumentation Module) Bay. A high-resolution camera as well as radiation measurement devices were carried here to probe the surface of the moon from lunar orbit. Sector 2An RCS engine quad and a radiator panel are installed on the outside panel of this sector. An oxidizer sump tank for the SPS engine, and an RCS fuel tank and conduits are installed inside. The oxidizer sump tank can hold 13923lb of nitrogen tetroxide, and is manufactured of titanium, with a height 153.8 inches, and a diameter of 51 inches. Sector 3An RCS engine quad and a radiator panel are installed on the outside panel of this sector. An oxidizer tank for the SPS engine, and an RCS fuel tank and conduits are installed inside. The oxidizer tank is a little smaller than the oxidizer sump tank, and carries 11284lb of oxidizer, with a height 154.47 inches, and a diameter of 45 inches. Sector 4
The center of the sector is equipped with two cryogenic oxygen tanks,
and two cryogenic hydrogen tanks are arranged under that in top and bottom.
All of these are globular forms, and supplies oxygen and hydrogen to the fuel cell powerplants.
The cryogenic oxygen tank is made of about diameter 26-inch Inconel (the alloy of the nickel and the iron).
It carries oxygen of 326lb under the condition of the semi-liquid, semi-gas state.
The cryogenic hydrogen tank is made of about diameter 31.75-inch titanium.
It carries hydrogen of little over 29lb under the condition of the semi-liquid, semi-gas state.
APOLLO 13 fell into the critical conditions due to the explosion of No.2 cryogenic oxygen tank carried here.
Therefore, one spare cryogenic oxygen tank on sector 1 and one spare battery for the fuel battery trouble on sector 4
were added after APOLLO 13.
-->Three fuel cell power plants, two cryogenic oxygen tanks, two cryogenic hydrogen tanks, and the related infrastructure is installed here. The three fuel cell power plants are located at the top of the sector, and each has a height of 44 inches, a diameter of 22 inches, and weighs 245lb. These supply electric power and drinking water to the spacecraft. The center of this sector contains the two cryogenic oxygen tanks, and the two cryogenic hydrogen tanks, arranged with the oxygen tanks at the top, and the hydrogen tanks at the bottom. All of these tanks are spherical and supply oxygen and hydrogen to the fuel cell power plants. The cryogenic oxygen tank is made of about 26-inch diameter Inconel (an alloy made of nickel and iron). It carries 326lb of super-cooled oxygen, in a semi-liquid, semi-gas state. The cryogenic hydrogen tank is made of about 31.75-inch diameter titanium. It carries a little over 29lb of super-cooled hydrogen, in a semi-liquid, semi-gas state. The Apollo 13 emergency was due to the explosion of the Number 2 cryogenic oxygen tank carried here. Therefore, one spare cryogenic oxygen tank in Sector 1, and one spare battery in Sector 4 were added after Apollo 13. Sector 5An RCS engine quad and an environmental control radiator panel are installed on the outside panel of this sector. A fuel sump tank for the SPS engine, and an RCS fuel tank and conduits are installed inside. The fuel sump tank can hold 8708lb of propellant (a 50-50 mixture of hydrazine and unsymmetrical dimethylhydrazine), and is manufactured of titanium with a height of 153.8 inches, and a diameter of 51 inches. Sector 6An RCS engine quad and an environmental control radiator panel are installed on the outside panel of this sector. A fuel storage tank for the SPS engine, and an RCS fuel tank and conduits are installed inside. The size of the fuel storage tank is same as the oxidizer tank in Sector 3, and carries 7058lb of propellant, and has a height of 154.47 inches, and a diameter of 45 inches. Antenna
High-gain antenna is composed of four 31-inch diameter reflectors surrounding an 11-inch square reflector.
This is the directional antenna and it can't communicate if it doesn't face the direction of the earth precisely.
Toward this, the omnidirectional antennas hardly takes an influence in the direction comparatively.
And it is called scimitars from the shape.
It is used with INCO(Instrumental and Communication Officer) changing it
to the antenna where receiving conditions are better (faces to the earth).
The omnidirectional antenna is made of thickness 1/ 100-inch stainless steel and the entire length is about 13.5 inches.
-->There are two antenna systems, for communications and telemetry transmissions with NASA. One antenna, the S-band high-gain antenna was located off to the side of the SPS engine. The other was comprised of two sets of VHF omnidirectional antennas on the center of the SM body. The high-gain antenna is composed of four 31-inch diameter round reflectors surrounding an 11-inch square reflector. This is a directional antenna, and it cannot communicate if it is not precisely facing the direction of the Earth. In contrast, the omnidirectional antennas do not need to be pointed at the Earth. These were called "scimitars" due to their shape. The INCO (Instrumental and Communication Officer) would select which antenna to use based on the spacecraft's orientation, typically using the high-gain whenever it was facing the earth. The omnidirectional antenna is made of 1/100-inch stainless steel, and the entire length is about 13.5 inches. RCS engineAn RCS (reaction control subsystem) engine is a small rocket engine which is used to control the orientation of the spacecraft. The SM has four RCS quads installed (16 total engines), and these are installed with a 7 degree offset toward the +Z, -Z, +Y, and -Y axes. Monomethyl hydrazine (MMH) is used as fuel, and nitrogen tetroxide (N2O4) is used as oxidizer. Each of these engines has an output of 100 pounds of thrust. Two fuel tanks, two oxidizer tanks, and one helium tank are installed inside of the SM body. The oxidizer is mixed with the fuel in a 2:1 ratio, and ignites due to spontaneous combustion, and does not need any sort of spark to ignite. SPS engine
Aft heat shield surrounds SPS engine, it protects SM from the jetting heat of the SPS engine.
-->The SPS engine supplies the thrust necessary for Lunar Orbit Insertion (LOI), transearth injection (TEI), and midcourse corrections during flight. The SPS engine itself is 3 feet 5 inches, and has an engine bell or nozzle is 9 feet 4 inches, made of columbium and titanium attached. The entire weight of the SPS with fuel tanks is 41500 pounds, and occupies 75% of the SM. Its output is 20500 pounds of thrust. A 50:50 mix of hydrazine and unsymmetrical dimethylhydrazine (UDMH) is used as fuel, with nitrogen tetroxide used as oxidizer. No spark is necessary to light the engine, as these materials spontaneously combust when mixed. There is no throttle in this engine. Changing the ignition time (about 750 seconds from 0.4 seconds) allows for adjustment of the engine output. The SPS is rated to be started about 50 times. SPS ignition occurs after short firing (ullage maneuver) by the RCS engines, to help settle the fuel at the bottom of the tanks in the zero gravity environment. The SPS engine is installed on a gimbal ring, and can rotate +10 to -10 degrees around the Z (Yaw) axis, and +6 to -6 degrees around Y (Pitch) axis. Because the SM center of gravity changes during flight (due to fuel, water, oxygen, etc. usage), "straight" is actually +1 degree around the Z axis and -2 degrees around the Y axis. The engine is produced by AerojetGeneral Corp. in Sacramento, California. A heat shield in installed on the end of the SM where the SPS engine bell is attached, protecting the SM from the heat of the SPS engine. Connection, separation with CM
The disjunction of SM and CM is done automatically by the controller installed in SM.
Cutting of the connectors, the transfer of the control of the electric system, jetting of the SM RCS engine to draw CM and SM apart
are done momentarily at the time of the disjunction.
First, before the disjunction, astronauts do pressure of CM RCS by using the electric power of SM.
A disjunction sequence begins when either one of two disjunction switchs on main console is put next.
The electric system of the CM-SM umbilical inside is turned off first.
For 10 seconds rest, tension ties which connects SM with CM is separated.
At the same time with it, by the guillotine cutter of stainless steel to move by the explosive,
cables and wires in the CM-SM umbilical is cut.
Furthermore, Roll-RCS engine of SM jets for five seconds, the flight course of SM is changed, a collision with separated CM is avoided.
At the end, Until fuel is used up or electric power disappears, thrust engine of SM keeps jetting, and SM goes away from CM.
-->Six beams made of aluminum alloys are arranged at the forward bulkhead. Compression pads are installed in three of these. Tension ties that connect the CM and SM are installed with compression pads in the other three. The CM and SM are connected by these tension ties and the CM/SM umbilical which supplies electric power, oxygen, water, and so on. The separation of the SM and CM is done automatically by a controller installed in the SM. Cutting of the connectors, the transfer of the control of the electric system and jetting of the SM RCS engine to draw CM and SM apart are done almost instantaneously at the time of the separation. First, before the separation, astronauts pressurize the CM RCS by using electrical power provided by the SM. The separation sequence begins when either one of two switches on the main console is toggled. The electrical transfer through the CM-SM umbilical is disabled first. After 10 seconds, the tension ties that connect the SM with the CM are separated. At the same time, the stainless steel guillotine cutter is fired by explosives, cutting the cables and wires in the CM-SM umbilical. Finally, the RCS engines of the SM fire for five seconds, the flight course of SM is changed to avoid a collision with the CM. Until the fuel is used up or electric power is expended, the SM RCS keeps firing to ensure that the SM's flight path stays away from the CM.
The center of the sector is equipped with two cryogenic oxygen tanks,
and two cryogenic hydrogen tanks are arranged under that in top and bottom.
All of these are globular forms, and supplies oxygen and hydrogen to the fuel cell powerplants.
The cryogenic oxygen tank is made of about diameter 26-inch Inconel (the alloy of the nickel and the iron).
It carries oxygen of 326lb under the condition of the semi-liquid, semi-gas state.
The cryogenic hydrogen tank is made of about diameter 31.75-inch titanium.
It carries hydrogen of little over 29lb under the condition of the semi-liquid, semi-gas state.
APOLLO 13 fell into the critical conditions due to the explosion of No.2 cryogenic oxygen tank carried here.
Therefore, one spare cryogenic oxygen tank on sector 1 and one spare battery for the fuel battery trouble on sector 4
were added after APOLLO 13.
-->Three fuel cell power plants, two cryogenic oxygen tanks, two cryogenic hydrogen tanks, and the related infrastructure is installed here. The three fuel cell power plants are located at the top of the sector, and each has a height of 44 inches, a diameter of 22 inches, and weighs 245lb. These supply electric power and drinking water to the spacecraft. The center of this sector contains the two cryogenic oxygen tanks, and the two cryogenic hydrogen tanks, arranged with the oxygen tanks at the top, and the hydrogen tanks at the bottom. All of these tanks are spherical and supply oxygen and hydrogen to the fuel cell power plants. The cryogenic oxygen tank is made of about 26-inch diameter Inconel (an alloy made of nickel and iron). It carries 326lb of super-cooled oxygen, in a semi-liquid, semi-gas state. The cryogenic hydrogen tank is made of about 31.75-inch diameter titanium. It carries a little over 29lb of super-cooled hydrogen, in a semi-liquid, semi-gas state. The Apollo 13 emergency was due to the explosion of the Number 2 cryogenic oxygen tank carried here. Therefore, one spare cryogenic oxygen tank in Sector 1, and one spare battery in Sector 4 were added after Apollo 13. Sector 5An RCS engine quad and an environmental control radiator panel are installed on the outside panel of this sector. A fuel sump tank for the SPS engine, and an RCS fuel tank and conduits are installed inside. The fuel sump tank can hold 8708lb of propellant (a 50-50 mixture of hydrazine and unsymmetrical dimethylhydrazine), and is manufactured of titanium with a height of 153.8 inches, and a diameter of 51 inches. Sector 6An RCS engine quad and an environmental control radiator panel are installed on the outside panel of this sector. A fuel storage tank for the SPS engine, and an RCS fuel tank and conduits are installed inside. The size of the fuel storage tank is same as the oxidizer tank in Sector 3, and carries 7058lb of propellant, and has a height of 154.47 inches, and a diameter of 45 inches. Antenna
High-gain antenna is composed of four 31-inch diameter reflectors surrounding an 11-inch square reflector.
This is the directional antenna and it can't communicate if it doesn't face the direction of the earth precisely.
Toward this, the omnidirectional antennas hardly takes an influence in the direction comparatively.
And it is called scimitars from the shape.
It is used with INCO(Instrumental and Communication Officer) changing it
to the antenna where receiving conditions are better (faces to the earth).
The omnidirectional antenna is made of thickness 1/ 100-inch stainless steel and the entire length is about 13.5 inches.
-->There are two antenna systems, for communications and telemetry transmissions with NASA. One antenna, the S-band high-gain antenna was located off to the side of the SPS engine. The other was comprised of two sets of VHF omnidirectional antennas on the center of the SM body. The high-gain antenna is composed of four 31-inch diameter round reflectors surrounding an 11-inch square reflector. This is a directional antenna, and it cannot communicate if it is not precisely facing the direction of the Earth. In contrast, the omnidirectional antennas do not need to be pointed at the Earth. These were called "scimitars" due to their shape. The INCO (Instrumental and Communication Officer) would select which antenna to use based on the spacecraft's orientation, typically using the high-gain whenever it was facing the earth. The omnidirectional antenna is made of 1/100-inch stainless steel, and the entire length is about 13.5 inches. RCS engineAn RCS (reaction control subsystem) engine is a small rocket engine which is used to control the orientation of the spacecraft. The SM has four RCS quads installed (16 total engines), and these are installed with a 7 degree offset toward the +Z, -Z, +Y, and -Y axes. Monomethyl hydrazine (MMH) is used as fuel, and nitrogen tetroxide (N2O4) is used as oxidizer. Each of these engines has an output of 100 pounds of thrust. Two fuel tanks, two oxidizer tanks, and one helium tank are installed inside of the SM body. The oxidizer is mixed with the fuel in a 2:1 ratio, and ignites due to spontaneous combustion, and does not need any sort of spark to ignite. SPS engine
Aft heat shield surrounds SPS engine, it protects SM from the jetting heat of the SPS engine.
-->The SPS engine supplies the thrust necessary for Lunar Orbit Insertion (LOI), transearth injection (TEI), and midcourse corrections during flight. The SPS engine itself is 3 feet 5 inches, and has an engine bell or nozzle is 9 feet 4 inches, made of columbium and titanium attached. The entire weight of the SPS with fuel tanks is 41500 pounds, and occupies 75% of the SM. Its output is 20500 pounds of thrust. A 50:50 mix of hydrazine and unsymmetrical dimethylhydrazine (UDMH) is used as fuel, with nitrogen tetroxide used as oxidizer. No spark is necessary to light the engine, as these materials spontaneously combust when mixed. There is no throttle in this engine. Changing the ignition time (about 750 seconds from 0.4 seconds) allows for adjustment of the engine output. The SPS is rated to be started about 50 times. SPS ignition occurs after short firing (ullage maneuver) by the RCS engines, to help settle the fuel at the bottom of the tanks in the zero gravity environment. The SPS engine is installed on a gimbal ring, and can rotate +10 to -10 degrees around the Z (Yaw) axis, and +6 to -6 degrees around Y (Pitch) axis. Because the SM center of gravity changes during flight (due to fuel, water, oxygen, etc. usage), "straight" is actually +1 degree around the Z axis and -2 degrees around the Y axis. The engine is produced by AerojetGeneral Corp. in Sacramento, California. A heat shield in installed on the end of the SM where the SPS engine bell is attached, protecting the SM from the heat of the SPS engine. Connection, separation with CM
The disjunction of SM and CM is done automatically by the controller installed in SM.
Cutting of the connectors, the transfer of the control of the electric system, jetting of the SM RCS engine to draw CM and SM apart
are done momentarily at the time of the disjunction.
First, before the disjunction, astronauts do pressure of CM RCS by using the electric power of SM.
A disjunction sequence begins when either one of two disjunction switchs on main console is put next.
The electric system of the CM-SM umbilical inside is turned off first.
For 10 seconds rest, tension ties which connects SM with CM is separated.
At the same time with it, by the guillotine cutter of stainless steel to move by the explosive,
cables and wires in the CM-SM umbilical is cut.
Furthermore, Roll-RCS engine of SM jets for five seconds, the flight course of SM is changed, a collision with separated CM is avoided.
At the end, Until fuel is used up or electric power disappears, thrust engine of SM keeps jetting, and SM goes away from CM.
-->Six beams made of aluminum alloys are arranged at the forward bulkhead. Compression pads are installed in three of these. Tension ties that connect the CM and SM are installed with compression pads in the other three. The CM and SM are connected by these tension ties and the CM/SM umbilical which supplies electric power, oxygen, water, and so on. The separation of the SM and CM is done automatically by a controller installed in the SM. Cutting of the connectors, the transfer of the control of the electric system and jetting of the SM RCS engine to draw CM and SM apart are done almost instantaneously at the time of the separation. First, before the separation, astronauts pressurize the CM RCS by using electrical power provided by the SM. The separation sequence begins when either one of two switches on the main console is toggled. The electrical transfer through the CM-SM umbilical is disabled first. After 10 seconds, the tension ties that connect the SM with the CM are separated. At the same time, the stainless steel guillotine cutter is fired by explosives, cutting the cables and wires in the CM-SM umbilical. Finally, the RCS engines of the SM fire for five seconds, the flight course of SM is changed to avoid a collision with the CM. Until the fuel is used up or electric power is expended, the SM RCS keeps firing to ensure that the SM's flight path stays away from the CM.
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