RS-27A (rocket engine)
Encyclopedia
The RS-27A is a liquid-fuel rocket engine developed by Rocketdyne
for use on the first stage of the Delta II
and Delta III launch vehicles. It provides 1.05 meganewtons of thrust burning RP-1
and LOX
in a gas-generator
cycle. The engine is a modified version of its predecessor, the RS-27; its thrust nozzle has been extended to increase its area ratio from 8:1 to 12:1, which provides greater efficiency at altitude.
The RS-27A main engine is neither restartable nor throttleable. In addition to its main engine, the RS-27A includes two vernier
engines to provide vehicle roll control during flight. The RS-27A has a run duration of 265 seconds.
Rocketdyne
Rocketdyne was a Rocket engine design and production company headquartered in Canoga Park, California, United States. The company was related to North American Aviation for most of its history. NAA merged with Rockwell International, which was then bought by Boeing in December, 1996...
for use on the first stage of the Delta II
Delta II
Delta II was an American space launch system, originally designed and built by McDonnell Douglas. Delta II is part of the Delta rocket family and was in service from 1989 until November 1, 2011...
and Delta III launch vehicles. It provides 1.05 meganewtons of thrust burning RP-1
RP-1
RP-1 is a highly refined form of kerosene outwardly similar to jet fuel, used as a rocket fuel. Although having a lower specific impulse than liquid hydrogen , RP-1 is cheaper, can be stored at room temperature, is far less of an explosive hazard and is far denser...
and LOX
Lox
Lox is salmon fillet that has been cured. In its most popular form, it is thinly sliced—less than in thickness—and, typically, served on a bagel, often with cream cheese, onion, tomato, cucumber and capers...
in a gas-generator
Gas-generator cycle (rocket)
The gas generator cycle is a power cycle of a bipropellant rocket engine. Some of the propellant is burned in a gas-generator and the resulting hot gas is used to power the engine's pumps. The gas is then exhausted...
cycle. The engine is a modified version of its predecessor, the RS-27; its thrust nozzle has been extended to increase its area ratio from 8:1 to 12:1, which provides greater efficiency at altitude.
The RS-27A main engine is neither restartable nor throttleable. In addition to its main engine, the RS-27A includes two vernier
Vernier thruster
A vernier thruster is a thruster used on a spacecraft for attitude control. It is a smaller thrust motor than main attitude control motors and is used for fine adjustments to the attitude or velocity of a spacecraft...
engines to provide vehicle roll control during flight. The RS-27A has a run duration of 265 seconds.
Specifications
- Source: Astronautix
- Thrust (vac): 237,000 lbf (1.05 MN)
- Specific impulse, Isp (vac): 302 s
- Isp (sea level): 255 s
- Mass: 2,528 lb (1,147 kg)
- Diameter: 67 in (1.70 m)
- Length: 12 ft 5 in (3.78 m)
- Chambers: 1
- Chamber pressure: 700 psia (4.8 MPa)
- Area ratio: 12:1
- Oxidizer to fuel ratio: 2.245:1
- Thrust to Weight ratio: 102