The S-V (pronounced "S-five") was the third stage of the

Saturn I The Saturn I was a rocket designed as the United States' first medium lift launch vehicle for up to low Earth orbit payloads.Terminology has changed since the 1960s; back then, 20,000 pounds was considered "heavy lift". The rocket's first stag ...

rocket. It was built by Convair. It was designed to use two RL-10A-1 engines fueled by

liquid hydrogen Liquid hydrogen (LH2 or LH2) is the liquid state of the element hydrogen. Hydrogen is found naturally in the molecular H2 form. To exist as a liquid, H2 must be cooled below its critical point of 33 K. However, for it to be in a fully li ...

(LH₂₎ and

liquid oxygen Liquid oxygen—abbreviated LOx, LOX or Lox in the aerospace, submarine and gas industries—is the liquid form of molecular oxygen. It was used as the oxidizer in the first liquid-fueled rocket invented in 1926 by Robert H. Goddard, an applica ...

(LOX) in tanks utilizing a common bulkhead to separate the propellants.

History

Convair Astronautics was awarded a contract to deliver the S-V stage for the

. The stage was intended to boost lift capacity for U.S. military launches in the 1960s. The S-V would ultimately fly as the third stage on early launches of the Saturn I. Convair delivered two S-V stages in February 1961 with one being flown on SA-1 attached to an also inert S-IV, the second was used for dynamic testing of the complete Saturn I before being later flown. In May 1961 NASA eliminated the requirement for all Saturn I launches to be flown with S-V's by flying in a two-stage only version. Despite this, the stage would fly four times in total. With the introduction of the Saturn IB and the needs of the military fulfilled on other launches, all further launches would be on either the

Saturn IB The Saturn IB (also known as the uprated Saturn I) was an American launch vehicle commissioned by the NASA, National Aeronautics and Space Administration (NASA) for the Apollo program. It uprated the Saturn I by replacing the S-IV second stage (, ...

Saturn V Saturn V is a retired American super heavy-lift launch vehicle developed by NASA under the Apollo program for human exploration of the Moon. The rocket was human-rated, with multistage rocket, three stages, and powered with liquid-propellant r ...

, each of which did not include the S-V. A version of this stage was also used on the Atlas-LV3C as the

Centaur A centaur ( ; grc, κένταυρος, kéntauros; ), or occasionally hippocentaur, is a creature from Greek mythology with the upper body of a human and the lower body and legs of a horse. Centaurs are thought of in many Greek myths as being ...

, modern derivatives of which are still flown today making it the only Saturn rocket stage still currently operating.

Flight history

Ultimately, the S-V would go on to fly four times between 1961 and 1964. Each of which were flown on suborbital test flights of the Saturn I. Because of the suborbital nature of these flights, each S-V was filled with water to act as ballast, making the stage inert. The water was released in space twice for

Project Highwater Project Highwater was an experiment carried out as part of two of the test flights of NASA's Saturn I launch vehicle (using battleship upper stages), successfully launched into a sub-orbital trajectory from Cape Canaveral, Florida. The Highwater ...

. Modern derivatives of the stage are still in use today on the

Atlas V Atlas V is an expendable launch system and the fifth major version in the Atlas (rocket family), Atlas launch vehicle family. It was originally designed by Lockheed Martin, now being operated by United Launch Alliance (ULA), a joint venture be ...

and the planned

Vulcan Centaur Vulcan Centaur is a two-stage-to-orbit, heavy-lift launch vehicle that is under development by the United Launch Alliance (ULA) since 2014 with an initial flight expected in early 2023. It is principally designed to meet launch demands for the ...

. {, class="wikitable" , + !Flight Number !Launch date (UTC) !Notes , - , SA-1 , October 27, 1961 15:06:04 , First test suborbital flight. Apogee: 136.5 km. Inactive S-IV and S-V stages. , - , SA-2 , April 25, 1962 14:00:34 , Second suborbital test flight. 86,000 kg water released at apogee of 145 km. Inactive S-IV and S-V stages. , - ,

SA-3 The S-125 ''Neva/Pechora'' (russian: С-125 "Нева"/"Печора", NATO reporting name SA-3 ''Goa'') is a Soviet surface-to-air missile system that was designed by Aleksei Isaev to complement the S-25 and S-75. It has a shorter effective ra ...

, November 16, 1962 17:45:02 , Third suborbital test flight. 86,000 kg water released at apogee of 167 km. Inactive S-IV and S-V stages. , - , SA-4 , March 28, 1963 20:11:55 , Fourth suborbital test flight. Apogee: 129 km. Inactive S-IV and S-V stages.

References

__FORCETOC__ Rocket stages NASA space launch vehicles