The RS-27 was a

liquid-propellant rocket A liquid-propellant rocket or liquid rocket utilizes a rocket engine that uses liquid rocket propellant, liquid propellants. Liquids are desirable because they have a reasonably high density and high Specific impulse, specific impulse (''I''sp). T ...

engine developed in 1974 by Rocketdyne to replace the aging MB-3 in the Delta. Incorporating components of the venerable MB-3 and the H-1 designs, the RS-27 was a modernized version of the basic design used for two decades. It was used to power the first stage of the

Delta 2000 The Delta 2000 series was an American expendable launch system which was used to conduct forty-four orbital launches between 1974 and 1981. It was a member of the Delta family of rockets. Several variants existed, which were differentiated by a ...

3000 3000 or ''variation'', may refer to: * 3000 (number), the number three thousand * A.D. 3000, the last year of the 30th century and the 3rd millennium CE * 3000 BCE, a year in the 3rd millennium BC * 3000s AD, a decade, century, millennium in the 4 ...

, 5000, and the first model of the

Delta II Delta II was an expendable launch system, originally designed and built by McDonnell Douglas. Delta II was part of the Delta rocket family and entered service in 1989. Delta II vehicles included the Delta 6000, and the two later Delta 7000 va ...

, the Delta 6000. The RS-27 was a modified

Rocketdyne H-1 The Rocketdyne H-1 was a thrust liquid-propellant rocket engine burning LOX and RP-1. The H-1 was developed for use in the S-I and S-IB first stages of the Saturn I and Saturn IB rockets, respectively, where it was used in clusters of eight e ...

built to power the first 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 ...

and

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 (, ...

and replaced the MB-3 engine that had been used on previous versions of the Delta launcher. NASA had a large supply of surplus H-1 engines in the early 1970s, as the Apollo program was ending. In addition to its main engine, the RS-27 included two vernier engines to provide vehicle roll control during flight. RS-27 was later developed into the

RS-27A The RS-27A is a liquid-fuel rocket engine developed in 1980s by Rocketdyne for use on the first stage of the Delta II and Delta III launch vehicles. It provides of thrust burning RP-1 and LOX in a gas-generator cycle. The engine is a modified ver ...

and

RS-56 RS-56 was an American liquid-fueled rocket engine, developed by Rocketdyne. RS-56 was derived from the RS-27 rocket engine, which itself is derived from the Rocketdyne H-1 rocket engine used in the Saturn I and Saturn IB. Two variants of this en ...

References

Rocketdyne engines Rocket engines using the gas-generator cycle Rocket engines using kerosene propellant Rocket engines of the United States {{space-stub