5.3 KiB
| title | chunk | source | category | tags | date_saved | instance |
|---|---|---|---|---|---|---|
| Saturn V | 5/10 | https://en.wikipedia.org/wiki/Saturn_V | reference | science, encyclopedia | 2026-05-05T13:12:08.190587+00:00 | kb-cron |
==== Structure ==== The S-II consisted of a body shell structure (forward and aft skirts and interstage), a propellant tank structure (liquid hydrogen and liquid oxygen tanks), and a thrust structure. The three are of the same basic design except that the aft skirt and interstage were generally of heavier construction because of higher structural loads placed on them. Each unit is a cylindrical shell of semi-monocoque construction, built of 7075 aluminum alloy material, stiffened by external hat-section stringers and stabilized internally by circumferential ring frames. The forward skirt has a basic skin thickness of 0.10 cm (0.040 in), while the aft skirt and interstage both have basic skin thicknesses of 0.18 cm (0.071 in). The thrust structure, like the body shell structure, is of semi-monocoque construction but in the form of a truncated cone increasing in size from approximately 5.5 metres (18 ft) to 10 metres (33 ft) in diameter. It is stiffened by circumferential ring frames and hat-section stringers like the body shell structure. Four pairs of thrust longerons (two at each outboard engine location) and a center engine support beam distribute the thrust loads of the J-2 engines. The shell structure is of 7075 aluminum alloy. A fiberglass honeycomb heat shield, supported from the lower portion of the thrust structure, protects the stage base area from excessive temperatures. The liquid hydrogen tank consists of a long cylinder with a concave modified ellipsoidal bulkhead forward and a convex modified ellipsoidal bulkhead aft. The aft bulkhead is also used by the liquid oxygen tank. The liquid hydrogen tank wall is composed of six cylindrical sections. Wall sections and bulkheads are all fabricated from 2014 aluminum alloy and are joined together by fusion welding. The forward bulkhead has an 11 m (36 ft) diameter wide access manhole built into its center. The common bulkhead is an adhesive-bonded sandwich assembly employing facing sheets of 2014 aluminum alloy and fiberglass/phenolic honeycomb core to prevent heat transfer and retain the cryogenic properties of the two fluids to which it was exposed.
The liquid oxygen tank consists of ellipsoidal fore and aft halves. The tank is fitted with three ring-type slosh baffles to control propellant sloshing and minimize surface disturbances and cruciform baffles to prevent the generation of vortices at the tank outlet ducts and to minimize residuals. A six-port sump assembly located at the lowest point of the tank provides a fill and drain opening and openings for five engine feed lines.
==== Electrical and instrumentation systems ==== The S-II electrical system consists of the electrical power and electrical control subsystems. The electrical power system provides the stage with the electrical power source and distribution. The electrical power system consists of six DC bus systems and a ground supplied AC bus system. In flight, the electrical power system busses are energized by four zinc-silver oxide batteries. The electrical control system interfaces with the instrument unit (IU) to accomplish the mission requirements of the stage. The Launch Vehicle Digital Computer (LVDC) in the IU controls in-flight sequencing of stage functions through the stage switch selector. The stage switch selector can provide up to 112 individual outputs in response to the appropriate commands. These outputs are routed through the stage electrical sequence controller or the separation controller to accomplish the directed operation. The S-II instrumentation system consists of both operational and R&D measurement and telemetry systems. The measurement system monitors and measures conditions on the stage while the telemetry system transmits this information to ground stations. The measurement system consists of transducers, signal conditioners, and distribution equipment necessary to provide the required measurement ranges and to present suitably scaled signals to the telemetry system. The measurement system monitors numerous stage conditions and characteristics. This data is processed and conditioned into a form acceptable to the telemetry systems. The telemetry system accepts the signals produced by the measuring portion of the instrumentation system and transmits them to the ground stations. Telemetry equipment includes signal multiplexers, subcarrier oscillators, amplifiers, modulators, transmitters, RF power amplifiers, RF multiplexers and an omni-directional system of four antennas.
=== S-IVB third stage ===
The S-IVB stage was built by Douglas Aircraft Company at Huntington Beach, California. It had one Rocketdyne J-2 engine and used liquid hydrogen and liquid oxygen. The S-IVB used a common bulkhead to separate the two tanks. It was 17.86 m (58 ft 7 in) tall with a diameter of 6.60 m (21 ft 8 in) and was also designed with high mass efficiency, though not quite as aggressively as the S-II. The S-IVB had a dry mass of about 15,200 kg (33,600 lb) and, when fully fueled, weighed about 120,500 kg (265,600 lb). The S-IVB had a burn time of 165 seconds the first burn, and 312 seconds for the second burn. Its single J-2 engine produced 1,000 kN (225,000 lbf) of thrust.