Apollo spacecraft

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The Apollo spacecraft was designed as part of the Apollo Program, by the United States in the early 1960s to land man on the moon before 1970 and return them safely to earth.This goal was set forth by the late president Kennedy after the first flight of the Mercury Space Program. The spacecraft was made up of multiple units or stages that worked together to perform the mission of landing on the moon and returning safely to earth. The main components of the Apollo spacecraft were (going from top to bottom) the launch escape system, the Command Module, the Service Module, the Lunar Module and the lunar module adapter. These stages together would sit atop the launch vehicle.

The principle was Lunar Orbit Rendezvous: A rocket would launch the spacecraft to the moon. The spacecraft would fly to the moon and orbit it. A smaller portion of the spacecraft would land on the moon and return to lunar orbit. Then a portion of the spacecraft would return to earth.

Launch vehicles: Little Joe II, Saturn I, Saturn IB, and Saturn V.

1 Launch Escape System (LES)
2 Command Module (CM)
3 Service Module (SM)
4 Lunar Module (LM)
5 Spacecraft Lunar Module Adapter (SLA)
6 Abort modes

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Launch Escape System (LES)

Image:Launch escape system diagram.jpg

The purpose of the Apollo launch escape system was to pull the Command Module (which contained the crew cabin) away from the launch vehicle in an abort situation.

The emergency could be a pad fire, exploding launch vehicle or a launch vehicle going off course.

The Launch Escape System would work automatically (or through manual activation) to fire a solid fuel escape rocket and open a canard system to direct the Command Module away from, and off the path of, a launch vehicle in trouble. The Launch Escape System would then jettison and the Command Module would land with its parachute recovery system.

If the emergency happened on the launch pad, the Launch Escape System would lift the Command Module to a sufficient height to allow the recovery parachutes to deploy safely before coming in contact with the ground.

Major Components of the Launch Escape System (LES):
- Nose Cone - The nosecone of the LES contained sensors that determined the angle of attack, airspeed, and attitude of the spacecraft and launch vehicle. It relayed this information to the command module and the launch vehicle guidance system.
- "Q-Ball" - The "Q-Ball" was a white styrofoam sphere resembling a cue ball (hence the name) that had a conical hole in the bottom and which was placed over the nosecone of the LES. The purpose of the Q-Ball was to prevent the pitot tubes of the nosecone sensors from getting clogged by debris prior to launch. The Q-Ball was removed prior to launch by the Q-Ball extraction system. The Q-Ball was split in half vertically and held together by a 2 inch rubber band. A razor blade was pinched between the halves of the Q-Ball and positioned behind the rubber band. A wire rope was connected to the top and bottom of the razor blade and to both halves of the Q-Ball. The wire rope was routed through a pulley on the hammerhead crane at the top of the launch umbilical tower (LUT) down to a tube on the right side of the 360 foot level of the LUT. The wire rope was connected to a cylindrical weight inside a tube. The weight rested on a lever controlled by a pneumatic solenoid valve. When the valve was actuated from the Launch Control Center (LCC), the pneumatic pressure of 600 PSI GN2 (nitrogen gas) rotated the lever down allowing the weight to drop down the tube. The dropping weight pulled the wire rope, which pulled the blade cutting the rubber band, and the wire rope pulled the halves of the Q-Ball away from the launch vehicle.
- Canard Assembly - Pitch Motor - These worked in combination to direct the Command Module off a straight path and to the side during an emergency. This would direct the Command Module off the flight path of an exploding launch vehicle. It would also direct the Command Module to land off to the side of any launch pad fire and not land back in the middle of it.
- Tower Jettison Motor - A smaller solid fuel motor that jettisons the Launch Escape System after it is no longer needed. This usually happens after second stage ignition.
- Launch Escape Motor - The main solid fuel rocket motor that, firing through four rocket nozzles, pulls the Command Module rapidly away from a launch emergency.
- Launch Escape Tower - Assembly that attaches the Launch Escape System rocket motors to the Command Module.
- Boost Protective Cover - Hollow cone shaped structure that fits over the Command Module during launch. It protects the Command Module heat shield and windows during ascent through the atmosphere. It also protects the Command Module from rocket exhaust should the Launch Escape System fire.

Specifications:
- Total Length: 10.2 m
- Diameter: 0.66 m
- Total mass: 9,200 lb (4,170 kg)
- Thrust: 155,000 lbf (689 kN)

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Command Module (CM)

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Image:Command Module diagram.jpg

The Command Module was the control center for the Apollo spacecraft and living quarters for the crew. It contained the pressurized main crew cabin, crew couches, control and instrument panel, optical and electronic guidance systems, communications systems, environmental control system, batteries, heat shield, reaction control system, forward docking hatch, side hatch, five windows and the parachute recovery system.

Specifications:
- Crew: 3
- Crew cabin volume: 6.17 m³
- Length: 3.47 m
- Diameter: 3.90 m
- Mass: 5,806 kg
- Structure Mass: 1,567 kg
- Heat Shield Mass: 848 kg
- RCS Mass: 400 kg
- Recovery Equipment Mass: 245 kg
- Navigation Equipment Mass: 505 kg
- Telemetry Equipment Mass: 200 kg
- Electrical Equipment Mass: 700 kg
- Communications Systems Mass: 100 kg
- Crew Couches and Provisions Mass: 550 kg
- Environmental Control System Mass: 200 kg
- Mis. Contingency Mass: 200 kg
- RCS Thrust: 12 x 420 N
- RCS Propellants: N₂O₄/UDMH
- RCS Engine Propellants: 75 kg
- RCS Specific Impulse I_sp: 290 s (2.84 kN·s/kg)
- RCS Impulse: 257 kN·s
- Electric System Batteries: 20.0 kW·h, 1000 A·h

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Service Module (SM)

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Image:Service Module diagram.jpg

The Service Module was a portion of the spacecraft that is unpressurized and contains fuel cells, batteries, high gain antenna, radiators, water, oxygen, hydrogen, reaction control system, propellant to enter and leave lunar orbit, and service propulsion system. On Apollo 15, 16 and 17 it also carried a scientific instrument package, mapping camera and a small sub-satellite to study the moon.

A major portion of the service module is taken up by propellant and the main rocket engine that placed the Apollo spacecraft into and out of lunar orbit. The main rocket engine was also used for mid-course corrections between the earth and the moon. It was capable of multiple restarts.

It remained attached to the Command Module throughout the mission. It is jettisoned just prior to reentry into the earth's atmosphere.

Specifications:
- Length: 7.56 m
- Diameter: 3.90 m
- Mass: 24,523 kg
- Structure Mass: 1,910 kg
- Electrical Equipment Mass: 1,200 kg
- RCS Thrust: 16 × 440 N
- Propellants: N₂O₄/UDMH
- RCS Specific Impulse I_sp: 290 s (2.84 kN·s/kg)
- RCS Impulse: 3,517 kN·s
- Service Propulsion Engine (SPS) Engine Mass: 3,000 kg
- SPS Engine Thrust: 98 kN
- SPS Engine Propellants: N₂O₄/Aerozine_50 (UDMH/N2H4)
- SPS Engine Propellants: 18,413 kg
- SPS Engine Specific Impulse I_sp: 314 s (3.08 kN·s/kg)
- Spacecraft delta v: 2.804 km/s
- Electrical System: Fuel Cells
- Electric System: 6.30 average kW, 670 kW·h

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Lunar Module (LM)

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Image:Lunar Module diagram.jpg

The Lunar Module was the portion of the Apollo spacecraft that landed on the moon and returned to lunar orbit. It is divided into two major parts, the Descent Module and the Ascent Module. It was designed specifically for flight in space. It supplied life support systems for two astronauts for a total of four to five days. The spacecraft was designed and manufactured by the Grumman Aircraft Company led by Tom Kelly.

The Descent Module contains the landing gear, landing radar antenna, descent rocket engine, and fuel to land on the moon. It also had several cargo compartments used to carry among other things, the Apollo Lunar Surface Experiment Packages ALSEP, Mobile Equipment Cart (a hand pulled equipment cart - Apollo 14) the Lunar Rover (moon car - Apollo 15, 16 and 17), surface television camera, surface tools and lunar sample collection boxes.

The Ascent Module contains the crew cabin, instrument panels, overhead hatch/docking port, forward hatch, optical and electronic guidance systems, reaction control system, radar and communications antennas, ascent rocket engine and fuel to return to lunar orbit and rendezvous with the Apollo Command and Service Modules.

Specifications:
- Ascent Stage:
  - Crew: 2
  - Crew cabin volume: 6.65 m³
  - Height: 3.54 m
  - Diameter: 4.27 m
  - Ascent Stage Mass: 4,547 kg
  - Ascent Engine Propellants: 2,358 kg
  - RCS Thrust: 16 × 440 kN
  - RCS Propellants: N₂O₄/UDMH
  - RCS Specific Impulse I_sp: 290 s (2.84 kN·s/kg)
  - Ascent Engine Thrust: 16 kN
  - Ascent Engine Propellants: N₂O₄/Aerozine_50 (UDMH/N2H4)
  - Ascent Engine Engine Isp: 311 s (3.05 kN·s/kg)
  - Ascent Stage Delta V: 2.22 km/s
  - Electric System Batteries: 17 kW·h 800 A·h
- Descent Stage:
  - Height: 2.83 m
  - Diameter: 4.21 m
  - Landing Gear Diameter: 9.37 m
  - Descent Stage Mass: 10,149 kg
  - Descent Engine Propellants: 8,165 kg
  - Descent Engine Thrust: 44 kN
  - Descent Engine Propellants: N₂O₄/Aerozine_50 (UDMH/N2H4)
  - Descent Engine Engine Specific Impulse I_sp: 311 s (3.05 kN·s/kg)
  - Descent Stage Delta V: 2.47 km/s
  - Electric System Batteries: 33 kW·h, 1,600 A·h

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Spacecraft Lunar Module Adapter (SLA)

The Spacecraft Lunar Module Adapter (SLA) is an aluminum cone shaped structure that connects the Service Module to the Saturn S-IVB rocket stage. It also protects the Lunar Module during launch and ascent through the atmosphere. It is made up of four large panels that open from the top similar to flower petals.

The SLA is made from 42.5 mm thick aluminum honeycomb material. The exterior of the SLA is covered by a layer of cork nearly 1 mm thick and then painted white. The cork insulates the Lunar Module from atmospheric frictional heat generated durning launch and ascent.

Once in space, the Command and Service Module detach from the SLA. Then the four SLA panels are then opened and released from the S-IVB rocket stage. This uncovers and allows access to the Lunar Module. The Command and Service Module turns 180 degrees and docks with the Lunar Module and then pulls it free from the S-IVB rocket stage.

Specifications:
- Height: 28 ft (8.5 m)
- Diameter - Apex: 12 ft 10 in (3.9 m) Service Module end
- Diameter - Base: 21 ft 8 in (6.6 m) S-IVB end
- Weight: 4,050 lb (1,837 kg)
- Volume: 6,700 ft³ (190 m³), 5,000 ft³ (140 m³) usable

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