Rocketdyne H-1

H-1

An H-1 engine at the Udvar-Hazy Center
Country of origin	United States
First flight	27 October 1961 (1961-10-27)
Last flight	15 July 1975 (1975-07-15)
Designer	Rocketdyne
Manufacturer	Rocketdyne
Application	First stage
Successor	RS-27
Status	Retired
Liquid-fuel engine
Propellant	LOX / RP-1
Cycle	Gas-generator
Configuration
Chamber	1
Performance
Thrust, sea-level	900 kN (200,000 lbf)
Thrust-to-weight ratio	102.47
Chamber pressure	700 psi (4,800 kPa)
Specific impulse, vacuum	289 s (2.83 km/s)
Specific impulse, sea-level	255 s (2.50 km/s)
Burn time	155 seconds
Dimensions
Length	2.7 m (8.8 ft)
Diameter	1.5 m (4.9 ft)
Dry mass	1,000 kg (2,200 lb)
Used in
Saturn I, Saturn 1B

The Rocketdyne H-1 was 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-I and S-IB first stages of the Saturn I and Saturn IB rockets, respectively, 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. RS-27 engines continued to be used up until 1992 when the first version of the Delta II, Delta 6000, was retired. The RS-27A variant, boasting slightly upgraded performance, was also used on the later Delta II and Delta III rockets, with the former flying until 2018.^[1][2]