A cluster of 8 H-1 rocket engines lifted the Saturn I from the launch pad.
|Country of origin||USA|
|Propellant||LOX / RP-1|
|Thrust (SL)||900 kN (205,000 lbf)|
|Chamber pressure||700 psia (4.8 MPa)|
|Isp (SL)||289 s|
|Burn time||155 s|
|Dry weight||1,000 kg (2,200 lb)|
|Saturn I, Saturn 1B|
Rocketdyne's H-1 is a 205,000 lbf (910 kN) thrust liquid-propellant rocket engine burning LOX and RP-1. The H-1 was developed for use in the S-IB first stage of the Saturn I and Saturn IB rockets, where it was used in clusters of eight engines. After the Apollo program, surplus H-1 engines were rebranded and reworked as the Rocketdyne RS-27 engine with first usage on the Delta 2000 series in 1974.
When Heinz-Hermann Koelle first drew up plans for what would become the Saturn, he selected Rocketdyne's E-1 to power it, with four engines in the lower stage. Rocketdyne was developing this 400,000 lbf (1,800 kN) engine for the Titan missile, and it was the largest engine nearing introduction within the time frame that ARPA gave Wernher von Braun to develop what was then known as the "Juno V". In 1957, after the launch of Sputnik 1, the U.S. developed plans to start a civilian space agency, which quickly developed into NASA. As the Army had lost interest in large rockets, they agreed to turn over von Braun's ABMA team to NASA, becoming the Marshall Space Flight Center. The handover would take place in 1960.
Shortly after these plans were made, ARPA visited ABMA and told von Braun that they still had $10 million in their budget to spend before the handover. They asked if there was anything they could do before the handover that could effectively use the money. Von Braun called in Koelle and showed them a model of the Juno V, but the ARPA visitors noted that the E-1 engine wouldn't be ready by 1960. Brainstorming, they decided that the best approach was to make a minor upgrade to Rocketdyne's existing 175,000 lbf engines to boost them to 200,000 lbf (890 kN), and use eight of these new H-1 engines instead of four E-1s. A contract for development was tendered on 15 August 1958, and by early 1959 the name had changed from Juno to Saturn, referring to the succession as the planet after Jupiter, the Jupiter missile being the previous ABMA design. Rocketdyne had several engine designs in the pipeline at that point, the E-1 and the F-1 being developed for the US Air Force.
Like all of Rocketdyne's early engines, the H-1 used a waterfall injector fed by turbopumps, and regeneratively cooled the engine using the engine's fuel.
Unlike the J-2 engine used on the S-IVB stage, the H-1 was a single-start engine. It could be fired multiple times—and engines were usually subject to two or more static test firings before a mission to flight-qualify them—but it could not be restarted in flight, because some components required for the startup sequence were non-reusable. In particular, the engine was ignited by a Solid Propellant Gas Generator (SPGG), which was essentially a small solid rocket, and had to be replaced after each firing.
To start the engine a 500V AC voltage was applied to the SPGG, which ignited the solid propellant. This produced hot gas which was allowed to build up until reaching a pressure of 600-700 psi, after which a bursting diaphragm released it into the turbine which drove the fuel turbopumps. This began the process of pumping fuel and oxidizer into the engine, and the hot gases from the SPGG provided the initial energy required to ignite the fuel/oxidizer mix. Once the fuel and oxidizer were being pumped and burning, the process was self-sustaining until engine shutdown.
- Contractor: NAA/Rocketdyne
- Vehicle Application: Saturn I / S-I 1st stage - 8 engines
- Vehicle Application: Saturn IB / S-IB 1st stage - 8 engines
|SA-201 through SA-205||SA-206 and subsequent|
|Thrust (sea level)||200,000 lbf (890 kN)||205,000 lbf (910 kN)|
|Thrust duration||155 s||155 s|
|Specific impulse||289 s||289 s|
|Engine weight dry (inboard)||1,830 pounds (830 kg)||2,200 pounds (1,000 kg)|
|Engine weight dry (outboard)||2,100 pounds (950 kg)||2,100 pounds (950 kg)|
|Engine weight burnout||2,200 pounds (1,000 kg)||2,200 pounds (1,000 kg)|
|Exit-to-throat area ratio||8:1||8:1|
|Propellants||LOX & RP-1||LOX & RP-1|
|Fuel flow rate||2092 USgal/min (132 L/s)|
|Oxidizer flow rate||3330 USgal/min (210 L/s)|
|Nominal chamber pressure||633 psi (4.36 MPa)|
- "Delta 2000 series". Encyclopedia Astronautica. Retrieved 8 June 2012.
- Kyle, Ed (9 April 2010). "Delta 2000 series - Extended Long Tank Delta". Space Launch Report. Retrieved 7 June 2012.
- Koelle, Juno V Feasibility, pp. 1-2; William A. Mrazek, "The Saturn Project," Astronautics, 5 (July 1960): 26-27; von Braun, "The Redstone, Jupiter, and Juno," in Emme, ed., History of Rocket Technology, pp. 107-119.
- Neufeld (2007), p. 331.
- Neufeld (2007), pp. 341–346.
- Bilstein (1996), pp. 27—28.
- Bilstein (1996), p. 37.
- Neufeld (2007), p. 318.
- Bilstein, Roger E. (1996). Stages to Saturn: A Technological History of the Apollo/Saturn Launch Vehicles. The NASA History Series. Washington: NASA. ISBN 978-0-16-048909-9. Archived from the original on 2004-10-15.
- Neufeld, Michael J. (2007). Von Braun: Dreamer of Space, Engineer of War. New York: Alfred A. Knopf. ISBN 978-0-307-26292-9.
- Skylab Saturn IB Flight Manual, 30 September 1972