4.7 KiB
| title | chunk | source | category | tags | date_saved | instance |
|---|---|---|---|---|---|---|
| Saturn V | 4/10 | https://en.wikipedia.org/wiki/Saturn_V | reference | science, encyclopedia | 2026-05-05T13:12:08.190587+00:00 | kb-cron |
==== Structure ==== The S-IC structure design reflects the requirements of the F-1 engines, propellants, control, instrumentation, and interfacing systems. The stage is primarily built of aluminum alloy, specifically 7075 and 2219 aluminum alloys. The major components are the forward skirt, oxidizer tank, intertank section, fuel tank, and thrust structure. The aft end of the forward skirt is attached to the oxidizer (liquid oxygen) tank and the forward end interfaces with the S-II. The skin panels, fabricated from 7075 aluminum, are stiffened and strengthened by ring frames and stringers. The 1,310,000 L (345,000 U.S. gal) liquid oxygen tank is the structural link between the forward skirt and the intertank section. Ring baffles attached to the skin stiffeners stabilize the tank wall and serve to reduce liquid oxygen sloshing. The tank is made of 2219 aluminum alloy and is a cylinder with ellipsoidal upper and lower bulkheads. The skin thickness is tapered in eight steps from 0.65 cm (0.254 in) at the aft section to 0.48 cm (0.190 in) at the forward section. The intertank structure helps provide structural continuity between the liquid oxygen and fuel tanks. The skin panels and ring frames are fabricated from 7075 aluminum. The 820,000 L (216,000 U.S. gal) fuel tank provides the structural link between the thrust and intertank structures. It is cylindrical with ellipsoidal upper and lower bulkheads. Anti-slosh ring baffles are located on the inside wall of the tank and anti-vortex cruciform baffles are located in the lower bulkhead area. Five liquid oxygen ducts run from the liquid oxygen tank, through the RP-1 tank, and terminate at the F-1 engines. The 2219 aluminum skin thickness is decreased in four steps from 0.49 cm (0.193 in) at the aft section to 0.43 cm (0.170 in) at the forward section.
The thrust structure assembly redistributes the loads of the five F-1 engines to the periphery of the fuel tank. It also provides support for the engine accessories, base heat shield, engine fairings and fins, propellant lines, retrorockets, and environmental control ducts. The lower thrust ring has four holddown points, which support the fully loaded rocket and, as necessary, restrain the vehicle from lifting off at full F-1 engine thrust. The skin segments are fabricated from 7075 aluminum alloy.
==== Electrical and instrumentation systems ==== The electrical power system of the S-IC is divided into three basic subsystems: an operational power subsystem, a measurement power subsystem, and a visual instrumentation power subsystem. On-board power is supplied by five 28-volt batteries, one each for the operational and measurement power systems. The operational power system battery supplies power to operational loads such as valve controls, purge and venting systems, pressurization systems, sequencing systems, and flight control. The measurement power system battery supplies power to measurement loads such as telemetry systems, transducers, multiplexers, and transmitters. Both batteries supply power to their loads through a common main power distributor, but each system is completely isolated from the others. In the visual instrumentation system, two batteries provide power for the liquid-oxygen tank strobe lights, while a third battery energizes the control circuits, camera motors, and thrusters of the film-camera portion of the visual instrumentation system. The instrumentation system monitors functional operations of stage systems and provides signals for vehicle tracking during the S-IC burn. Prior to liftoff, measurements were telemetered by coaxial cable to ground support equipment. During flight, data is transmitted to ground stations over radio frequency (RF) links. The offset Doppler (ODOP) system uses the Doppler principle to provide vehicle position and acceleration data during flight.
=== S-II second stage ===
The S-II was built by North American Aviation at Seal Beach, California. Using liquid hydrogen and liquid oxygen, it had five Rocketdyne J-2 engines arranged similarly to the S-IC, and also used the four outer engines for control. The S-II was 24.87 m (81 ft 7 in) tall with a diameter of 10 m (33 ft), identical to the S-IC. The S-II had a dry mass of about 43,000 kg (95,000 lb); when fully fueled, it weighed 470,000 kg (1,037,000 lb). The second stage accelerated the Saturn V through the upper atmosphere with 4,400 kN (1,000,000 lbf) of thrust in a vacuum. The S-II had a burn time of 395 seconds. When loaded with fuel, more than 90 percent of the mass of the stage was propellant.