RS-56 (Rocket System-56) was an American liquid-fueled rocket engine, developed by Rocketdyne. RS-56 was derived from the RS-27 rocket engine,[1] which itself is derived from the Rocketdyne H-1 rocket engine used in the Saturn I and Saturn IB. Two variants of this engine were built, both for use on the Atlas II rocket series. The first, RS-56-OBA, was a booster engine, while the RS-56-OSA was designed for use as a sustainer and produced lower thrust but at a higher specific impulse.[2][3]

RS-56
Country of originUnited States
First flight1991
ManufacturerRocketdyne
PredecessorRS-27A
StatusRetired
Liquid-fuel engine
PropellantLOX / RP-1
CycleGas-generator
Performance
Thrust, sea-levelRS-56-OBA: 207,000 lbf (920.8 kN)
RS-56-OSA: 60,500 lbf (269.0 kN)
Chamber pressure4.8 MPa (48 bar)
Specific impulse, vacuumRS-56-OBA: 299 s (2.93 km/s)
RS-56-OSA: 316 s (3.10 km/s)
Specific impulse, sea-levelRS-56-OBA: 263 s (2.58 km/s)
RS-56-OSA: 220 s (2.2 km/s)
Burn timeRS-56-OBA: 172
RS-56-OSA: 283 sec
Dimensions
LengthRS-56-OBA: 11.3 ft (3.43 m)
8.9 ft (2.7 m)
DiameterRS-56-OBA: 8.0 ft (2.45 m)
10.0 ft (3.05 m)
Used in
Atlas II

References

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  1. ^ "Atlas IIA(S) Data Sheet". Space Launch Report. Retrieved 9 January 2016.
  2. ^ "RS-56-OSA". Astronautix. Archived from the original on 9 February 2014. Retrieved 8 January 2016.
  3. ^ "RS-56-OBA". Astronautix. Archived from the original on 9 February 2014. Retrieved 8 January 2016.