The Saturn V (spoken as "Saturn five") was an American human-ratedexpendable rocket used by NASA's Apollo and Skylab
programs from 1966 until 1973. A multistage liquid-fueled launch vehicle, NASA launched 13 Saturn Vs from the Kennedy Space Center, Florida with no loss of crew or payload. It remains the tallest, heaviest, and most powerful rocket ever brought to operational status and still holds the record for heaviest payload launched and heaviest payload capacity to Low Earth orbit (LEO) of 118,000 kg (260,146 pounds)[2][3]. This was the official rating for the rocket by NASA but subsiquent missions (Apollo 15 in particular) allowed for a weight capacity of up to 240,000 kg to LEO.
programs from 1966 until 1973. A multistage liquid-fueled launch vehicle, NASA launched 13 Saturn Vs from the Kennedy Space Center, Florida with no loss of crew or payload. It remains the tallest, heaviest, and most powerful rocket ever brought to operational status and still holds the record for heaviest payload launched and heaviest payload capacity to Low Earth orbit (LEO) of 118,000 kg (260,146 pounds)[2][3]. This was the official rating for the rocket by NASA but subsiquent missions (Apollo 15 in particular) allowed for a weight capacity of up to 240,000 kg to LEO.
The largest production model of the Saturn family of rockets, the Saturn V was designed under the direction of Wernher von Braun and Arthur Rudolph at theMarshall Space Flight Center in Huntsville, Alabama, with Boeing, North American Aviation, Douglas Aircraft Company, and IBM as the lead contractors. Von Braun's design was based in part on his work on the Aggregate series of rockets, especially the A-10, A-11, and A-12, in Germany during World War II.
To date, the Saturn V is the only launch vehicle to transport human beings beyond low Earth orbit. A total of 24 astronauts were launched to the Moon, three of them twice, in the four years spanning December 1968 through December 1972.
 The final crewed Saturn V, AS-512, before the launch of Apollo 17 | |
| Function | Crewed LEO and Lunar launch vehicle |
|---|---|
| Manufacturer | Boeing (S-IC) North American (S-II) Douglas (S-IVB) |
| Country of origin | United States |
| Size | |
| Height | 363.0 feet (110.6 m) |
| Diameter | 33.0 feet (10.1 m) |
| Mass | 6,600,000 pounds (3,000,000 kg)[1] |
| Stages | 3 |
| Capacity | |
| Payload to LEO | 260,000 pounds (118,000 kg)[1] |
| Payload to TLI | 100,000 pounds (45,000 kg) |
| Associated rockets | |
| Family | Saturn |
| Derivatives | Saturn INT-21 |
| Comparable | N1 rocket |
| Launch history | |
| Status | Decommissioned |
| Launch sites | LC-39, Kennedy Space Center |
| Total launches | 13 |
| Successes | 12 |
| Failures | 0 |
| Partial failures | 1 (Apollo 6) |
| First flight | November 9, 1967 (SA-501) |
| Last flight | May 14, 1973 (Skylab 1) |
| First Stage - S-IC | |
| Length | 138.0 feet (42.1 m) |
| Diameter | 33.0 feet (10.1 m) |
| Empty mass | 288,000 pounds (131,000 kg) |
| Gross mass | 5,000,000 pounds (2,300,000 kg) |
| Engines | 5 Rocketdyne F-1 |
| Thrust | 7,648,000 pounds-force (34,020,000 N) |
| Specific impulse | 263 seconds (2.58 km/s) |
| Burn time | 165 seconds |
| Fuel | RP-1/LOX |
| Second Stage - S-II | |
| Length | 81.5 feet (24.8 m) |
| Diameter | 33.0 feet (10.1 m) |
| Empty mass | 80,000 pounds (36,000 kg) |
| Gross mass | 1,060,000 pounds (480,000 kg) |
| Engines | 5 Rocketdyne J-2 |
| Thrust | 1,000,000 pounds-force (4,400,000 N) |
| Specific impulse | 421 seconds (4.13 km/s) |
| Burn time | 360 seconds |
| Fuel | LH2/LOX |
| Third Stage - S-IVB | |
| Length | 61.6 feet (18.8 m) |
| Diameter | 21.7 feet (6.6 m) |
| Empty mass | 23,000 pounds (10,000 kg)[citation needed] |
| Gross mass | 266,400 pounds (120,800 kg) |
| Engines | 1 Rocketdyne J-2 |
| Thrust | 225,000 pounds-force (1,000,000 N) |
| Specific impulse | 421 seconds (4.13 km/s) |
| Burn time | 165 + 335 seconds (2 burns) |
| Fuel | LH2/LOX |
Selection for Apollo lunar landing
See also: Project Apollo § Choosing a mission mode
Early in the planning process, NASA considered three leading ideas for the Moon mission: Earth Orbit Rendezvous, Direct Ascent, and Lunar Orbit Rendezvous (LOR). A direct ascent configuration would launch a larger rocket which would land directly on the lunar surface, while an Earth orbit rendezvous would launch two smaller spacecraft which would combine in Earth orbit. A LOR mission would involve a single rocket launching a single spacecraft, but only a small part of that spacecraft would land on the moon. That smaller landing module would then rendezvous with the main spacecraft, and the crew would return home.[12]
NASA at first dismissed LOR as a riskier option, given that an orbital rendezvous had yet to be performed in Earth orbit, much less in lunar orbit. Several NASA officials, including Langley Research Center engineer John Houbolt and NASA Administrator George Low, argued that a Lunar Orbit Rendezvous provided the simplest landing on the moon, the most cost–efficient launch vehicle and, perhaps most importantly, the best chance to accomplish a lunar landing within the decade.[9] Other NASA officials were convinced, and LOR was officially selected as the mission configuration for the Apollo program on 7 November 1962.[9]
Lunar mission launch sequence
The Saturn V carried all Apollo lunar missions. All Saturn V missions launched from Launch Complex 39 at the John F. Kennedy Space Center in Florida. After the rocket cleared the launch tower, flight control transferred to Johnson Space Center's Mission Control in Houston, Texas.
An average mission used the rocket for a total of just 20 minutes. Although Apollo 6experienced three engine failures,[27] and Apollo 13 one engine shutdown,[28] the onboard computers were able to compensate by burning the remaining engines longer to achieve parking orbit. None of the Saturn V launches resulted in a payload loss.
S-IC sequence
The first stage burned for about 2 minutes and 41 seconds, lifting the rocket to an altitude of 42 miles (68 km) and a speed of 6,164 miles per hour (2,756 m/s) and burning 4,700,000 pounds (2,100,000 kg) of propellant.[29]
At 8.9 seconds before launch, the first stage ignition sequence started. The center engine ignited first, followed by opposing outboard pairs at 300-millisecond intervals to reduce the structural loads on the rocket. When thrust had been confirmed by the onboard computers, the rocket was "soft-released" in two stages: first, the hold-down arms released the rocket, and second, as the rocket began to accelerate upwards, it was slowed by tapered metal pins pulled through dies for half a second. Once the rocket had lifted off, it could not safely settle back down onto the pad if the engines failed. The astronauts considered this one of the tensest moments in riding the Saturn V, for if the rocket did fail to lift off after release they had a low chance of survival given the large amounts of propellant. A fully fueled Saturn V exploding on the pad would have released the energy equivalent of two kilotons of TNT. To improve the odds, the Saturn Emergency Detection System (EDS) inhibited engine shutdown for the first 30 seconds of flight. (See Saturn V Instrument Unit)
It took about 12 seconds for the rocket to clear the tower. During this time, it yawed 1.25 degrees away from the tower to ensure adequate clearance despite adverse winds. (This yaw, although small, can be seen in launch photos taken from the east or west.) At an altitude of 430 feet (130 m) the rocket rolled to the correct flight azimuth and then gradually pitched down until 38 seconds after second stage ignition. This pitch program was set according to the prevailing winds during the launch month. The four outboard engines also tilted toward the outside so that in the event of a premature outboard engine shutdown the remaining engines would thrust through the rocket's center of gravity. The Saturn V reached 400 feet per second (120 m/s) at over 1 mile (1,600 m) in altitude. Much of the early portion of the flight was spent gaining altitude, with the required velocity coming later. The Saturn V broke the sound barrier at just over 1 minute at an altitude of between 3 and 4 nautical miles. At this point, shock collars, or condensation clouds, could be seen forming around the bottom of the command module and around the top of the second stage.
At about 80 seconds, the rocket experienced maximum dynamic pressure (max Q). Thedynamic pressure on a rocket varies with air density and the square of relative velocity. Although velocity continues to increase, air density decreases so quickly with altitude that dynamic pressure falls below max Q.
Acceleration increased during S-IC flight for three reasons. One, increased acceleration increased the propellant pressure at the engines, increasing the flow rate somewhat. This was the least important factor, though this feedback effect often led to an undesirable thrust oscillation called pogo. Two, as it climbed into thinner air F-1 engine efficiency increased significantly, a property of all rockets. The combined thrust of five engines on the pad was about 7.5 million pounds, reaching nearly 9 million pounds at altitude. But the biggest contribution by far was the rocket's rapidly decreasing mass. The propellant in just the S-IC made up about three-quarters of Saturn V's entire launch mass, and it was furiously consumed at over 13 metric tonnes per second. Newton's second law states that force is equal to mass times acceleration, or equivalently that acceleration is equal to force divided by mass, so as the mass decreased (and the force increased somewhat), acceleration rose. Including gravity, launch acceleration was only 1 1/4 g, i.e., the astronauts felt 1 1/4 g while the rocket accelerated vertically at 1/4 g. As the rocket rapidly lost mass, total acceleration including gravity increased to nearly 4 g at T+135 seconds.
It would have increased further except that at 135 seconds the inboard (center) engine shut down to prevent it. Acceleration then resumed its increase, again reaching nearly 4 g on the remaining 4 engines when oxidizer and/or fuel depletion was sensed in the suction assemblies. First stage separation occurred a little less than one second after cutoff to allow for F-1 thrust tail-off. Eight small solid fuel separation motors backed the S-IC from the interstage at an altitude of about 67 kilometers (42 mi). The first stage continued ballistically to an altitude of about 109 kilometers (68 mi) and then fell in the Atlantic Ocean about 560 kilometers (350 mi) downrange...OP+
