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| title | chunk | source | category | tags | date_saved | instance |
|---|---|---|---|---|---|---|
| Apollo command and service module | 5/7 | https://en.wikipedia.org/wiki/Apollo_command_and_service_module | reference | science, encyclopedia | 2026-05-05T12:35:22.001294+00:00 | kb-cron |
Crew: 3 Crew cabin volume: 210 ft3 (5.9 m3) living space, pressurized 366 ft3 (10.4 m3) Length: 11.4 ft (3.5 m) Diameter: 12.8 ft (3.9 m) Mass: 12,250 lb (5,560 kg) Structure mass: 3,450 lb (1,560 kg) Heat shield mass: 1,869 lb (848 kg) RCS engine mass: 12 × 73.3 lb (33.2 kg) Recovery equipment mass: 540 lb (240 kg) Navigation equipment mass: 1,113 lb (505 kg) Telemetry equipment mass: 440 lb (200 kg) Electrical equipment mass: 1,540 lb (700 kg) Communications systems mass: 220 lb (100 kg) Crew couches and provisions mass: 1,210 lb (550 kg) Environmental Control System mass: 440 lb (200 kg) Misc. contingency mass: 440 lb (200 kg) RCS: twelve 93 lbf (410 N) thrusters, firing in pairs RCS propellants: MMH/N2O4 RCS propellant mass: 270 lb (120 kg) Drinking water capacity: 33 lb (15 kg) Waste water capacity: 58 lb (26 kg) CO2 scrubber: lithium hydroxide Odor absorber: activated charcoal Electric system batteries: three 40 ampere-hour silver-zinc batteries; two 0.75 ampere-hour silver-zinc pyrotechnic batteries Parachutes: two 16.5-foot (5.0 m) conical ribbon drogue parachutes; three 7.2-foot (2.2 m) ringslot pilot parachutes; three 83.5-foot (25.5 m) ringsail main parachutes Sources:
== Service module (SM) ==
=== Construction === The service module was an unpressurized cylindrical structure with a diameter of 12 feet 10 inches (3.91 m) and 14 feet 10 inches (4.52 m) long. The service propulsion engine nozzle and heat shield increased the total height to 24 feet 7 inches (7.49 m). The interior was a simple structure consisting of a central tunnel section 44 inches (1.1 m) in diameter, surrounded by six pie-shaped sectors. The sectors were topped by a forward bulkhead and fairing, separated by six radial beams, covered on the outside by four honeycomb panels, and supported by an aft bulkhead and engine heat shield. The sectors were not all equal 60° angles, but varied according to required size.
Sector 1 (50°) was originally unused, so it was filled with ballast to maintain the SM's center-of gravity. On the last three lunar landing (J-class) missions, it carried the scientific instrument module (SIM) with a powerful Itek 24-inch (610 mm) focal length camera originally developed for the Lockheed U-2 and SR-71 reconnaissance aircraft. The camera photographed the Moon; had the S-IVB failed to fire causing the CSM to not leave earth orbit, astronauts would have used it to photograph the Earth. SIM also had other sensors and a subsatellite. Sector 2 (70°) contained the service propulsion system (SPS) oxidizer sump tank, so called because it directly fed the engine and was kept continuously filled by a separate storage tank, until the latter was empty. The sump tank was a cylinder with hemispherical ends, 153.8 inches (3.91 m) high, 51 inches (1.3 m) in diameter, and contained 13,923 pounds (6,315 kg) of oxidizer. Its total volume was 161.48 ft3 (4.573 m3). Sector 3 (60°) contained the SPS oxidizer storage tank, which was the same shape as the sump tank but slightly smaller at 154.47 inches (3.924 m) high and 44 inches (1.1 m) in diameter, and held 11,284 pounds (5,118 kg) of oxidizer. Its total volume was 128.52 ft3 (3.639 m3). Sector 4 (50°) contained the electrical power system (EPS) fuel cells with their hydrogen and oxygen reactants. Sector 5 (70°) contained the SPS fuel sump tank. This was the same size as the oxidizer sump tank and held 8,708 pounds (3,950 kg) of fuel. Sector 6 (60°) contained the SPS fuel storage tank, also the same size as the oxidizer storage tank. It held 7,058 pounds (3,201 kg) of fuel. The forward fairing measured 1 foot 11 inches (58 cm) long and housed the reaction control system (RCS) computer, power distribution block, ECS controller, separation controller, and components for the high-gain antenna, and included eight EPS radiators and the umbilical connection arm containing the main electrical and plumbing connections to the CM. The fairing externally contained a retractable forward-facing spotlight; an EVA floodlight to aid the command module pilot in SIM film retrieval; and a flashing rendezvous beacon visible from 54 nautical miles (100 km) away as a navigation aid for rendezvous with the LM. The SM was connected to the CM using three tension ties and six compression pads. The tension ties were stainless steel straps bolted to the CM's aft heat shield. It remained attached to the command module throughout most of the mission, until being jettisoned just prior to re-entry into the Earth's atmosphere. At jettison, the CM umbilical connections were cut using a pyrotechnic-activated guillotine assembly. Following jettison, the SM aft translation thrusters automatically fired continuously to distance it from the CM, until either the RCS fuel or the fuel cell power was depleted. The roll thrusters were also fired for five seconds to make sure it followed a different trajectory from the CM and faster break-up on re-entry.
=== Service propulsion system ===