S IVB: Третья ступень ракеты-носителя "Сатурн-V" и вторая ступень "Сатурн-IB"

Third stage on the Saturn V and second stage on the Saturn IB

The S IVB (pronounced "S four B") was the third stage on the Saturn V and second stage on the Saturn IB launch vehicles. Built by the Douglas Aircraft Company, it had one J 2 rocket engine. For lunar missions it was fired twice: first for Earth orbit insertion after second stage cutoff, and then for translunar injection (TLI).

The S IVB evolved from the upper stage of the Saturn I rocket (the S IV) and was the first stage of the Saturn V to be designed. The S IV used a cluster of six RL 10 engines but used the same fuels as the S IVB – liquid hydrogen and liquid oxygen. It was also originally meant to be the fourth stage of a planned rocket called the C 4, hence the name S IV. Eleven companies submitted proposals for being the lead contractor on the stage by the deadline of 29 February 1960. NASA administrator T. Keith Glennan decided on 19 April that Douglas Aircraft Company would be awarded the contract. Convair had come in a close second but Glennan did not want to monopolize the liquid hydrogen fueled rocket market as Convair was already building the Centaur stage of the Atlas Centaur rocket. In the end, the Marshall Space Flight Center decided to use the C 5 rocket (later called the Saturn V), which had three stages and would be topped with an uprated S IV called the S IVB featuring a single J 2 engine, as opposed to the cluster of 6 RL 10 engines on the S IV. Douglas was awarded the contract for the S IVB because of the similarities between it and the S IV. At the same time, it was decided to create the C IB rocket (Saturn IB) that would also use the S IVB as its second stage and could be used for testing the Apollo spacecraft in low Earth orbit. 12 200 series and 16 500 series S IVB stages were built, alongside 3 test stages. NASA was working on acquiring 4 additional 200 series stages (as part of 4 new Saturn IB rockets, SA 213 to 216), but funding never materialized and the order was canceled in August 1968 before S IVB hardware was assembled.

Attitude control was provided by J 2 engine gimbaling during powered flight and by the two APS modules during coast. APS modules were used for three axis control during coast phases, roll control during J 2 firings, and ullage for the second ignition of the J 2 engine.

200 series Serial number Use Launch date Current location NotesImageS IVB S"Battleship" static test stage Stacked on top of S IB 11 at the Alabama Welcome Center in Ardmore, AL Test article made with thicker stainless steel tanks (flight stages would use thinner aluminum tanks) for early propellant loading and engine tests. Assembly completed in mid 1964, began testing in September of the same year. S IVB FFacilities test stageAppears to have been scrapped in the 1990s Completed in early 1965, used later that year (without J 2 engine) to check out ground facilities at LC 34 and LC 37 at Cape Canaveral. Completed similar testing as part of SA 500F at KSC in 1965/1966. Modified in 1970 to become Skylab Dynamic Test vehicle. S IVB D"Dynamic" test stageU. S. Space & Rocket Center, Huntsville, Alabama Assembly completed in 1964. Delivered to Marshall Space Flight Center in January 1965; also used for structural testing as part of SA 500D in 1967. First S IVB to fly; suborbital Saturn IB mission. S IVB 202AS 202August 25, 1966Suborbital test; impacted Atlantic Ocean Suborbital Saturn IB mission; J 2 engine ignition recorded via a camera on S IB stage. S IVB 203AS 203July 5, 1966Exploded in orbit during bulkhead test at end of mission; debris decayed Carried no payload in order to test the behavior of liquid hydrogen in weightlessness. Data used to validate J 2 restart possibility on 500 series S IVB. S IVB 204Apollo 5 (originally intended for Apollo 1)January 22, 1968Launched LM 1 into low Earth orbit for uncrewed test; decayed S IVB 205Apollo 7October 11, 1968Decayed from low Earth orbit S IVB 206Skylab 2, (crew to Skylab)May 25, 1973Decayed from low Earth orbit First Saturn IB launched from LC 39B. Stages 206 210 were produced in 1966/67 then stored at Huntington Beach until 1971. Refurbished and put through a second set of ground testing prior to being shipped to KSC. S IVB 509Apollo 14January 31, 1971Lunar surface* S IVB 510Apollo 15July 26, 1971Lunar surface* S IVB 511Apollo 16April 16, 1972Lunar surface* S IVB 512Apollo 17December 7, 1972Lunar surface* S IVB 513 Apollo 18 (cancelled)Johnson Space Center The other two stages of the SA 513 stack launched the Skylab space station to low Earth orbitS IVB 514 Apollo 19 (cancelled)Kennedy Space Center S IVB 515 Apollo 20 (cancelled), later converted to Skylab BNational Air and Space Museum Converted to Skylab B space station as a backup to Skylab. Proposed multiple times to be launched after Skylab, but funding never materialized and the station remained unused. (* See List of artificial objects on the Moon for location.)

The second stage of the Ares I rocket and the proposed Earth Departure Stage (EDS) would have had some of the characteristics of the S IVB stage, as both would have had an uprated J 2 engine, called the J 2X, with the latter performing the same functions as that of the Series 500 version of the stage (placing the payload into orbit, and later firing the spacecraft into trans lunar space). The MS IVB was a proposed modification of the S IVB that would have been used on a Mars flyby, but it was never produced.