RS-25

Also known as SSME, Aerojet Rocketdyne RS-25, Space Shuttle Main Engine, Rocket System 25

The RS-25, also known as the Space Shuttle Main Engine (SSME), is a liquid-fuel cryogenic rocket engine that was used on NASA's Space Shuttle and is used on the Space Launch System.

Key facts

Rocket engine.image_alt: A rocket engine firing. A blue flame is projecting from a bell-shaped nozzle with several pipes wrapped around it. The top of the nozzle is attached to a complex collection of plumbing, with the whole assembly covered in steam and hanging from a ceiling-mounted attachment point. Various pieces of transient hardware are visible in the background.
Rocket engine.caption: RS-25 test firing. The bright area at the bottom of the picture is a shock diamond.
Rocket engine.name: RS-25
Rocket engine.country_of_origin: United States
Rocket engine.designer: Rocketdyne
Rocket engine.predecessor: HG-3
Rocket engine.first_date: (STS-1)
Rocket engine.type: liquid
Rocket engine.oxidiser: LOX
Rocket engine.thrust_to_weight: 73.1
Rocket engine.cycle: Fuel-rich dual-shaft staged combustion
Rocket engine.nozzle_ratio: 78:1
Rocket engine.status: In use
Rocket engine.notes: Data is for RS-25D at 109% of rated power level.
Rocket engine.mixture_ratio: 6.03:1
Rocket engine.throttle_range: 67–109%
Rocket engine.image: Shuttle Main Engine Test Firing.jpg
Rocket engine.image_size: 250

via Wikipedia infobox

~51 min read

Encyclopedic overview

27 sections

Contents

Components
Turbopumps
Oxidizer system
Fuel system
Powerhead
Preburners
Main combustion chamber
Nozzle
Controller
Main valves
Gimbal
Helium system
History
Development
Space Shuttle program
Upgrades
Engine throttle/output
Incidents
Constellation
XS-1
Present use
Space Launch System
Engine tests
See also
Notes
References
External links

The RS-25, also known as the Space Shuttle Main Engine (SSME), is a liquid-fuel cryogenic rocket engine that was used on NASA's Space Shuttle and is used on the Space Launch System.

Designed and manufactured in the United States by Rocketdyne (later Pratt & Whitney Rocketdyne and Aerojet Rocketdyne), the RS-25 burns cryogenic (very low temperature) liquid hydrogen and liquid oxygen propellants, with each engine producing thrust at liftoff. Although RS-25 heritage traces back to the 1960s, its concerted development began in the 1970s with the first flight, STS-1, on April 12, 1981. The RS-25 has undergone upgrades over its operational history to improve the engine's thrust, reliability, safety, and maintenance load.

Excerpted from Wikipedia’s “RS-25” article, available under the CC BY-SA 4.0 licence.