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RL10 family

RL10 is a Pratt & Whitney-developed liquid-hydrogen/liquid-oxygen cryogenic upper-stage engine family first flown in 1963. NASA identifies the family as the propulsion of Centaur and later upper stages, with more than 500 RL10 engines flown; its expander cycle and evolved RL10A, RL10B, and RL10C models are represented by the child variants. Current RL10 production for Space Launch System missions is by L3Harris Technologies.

RL10 family
NASA/Paul Riedel (grc-1968-c-02664) · NASA imagery generally not subject to US copyright; factual/informational reuse under NASA Images and Media Usage Guidelines; credit NASA; no endorsement implied. Source page captions this as a publicity photo for the Pratt & Whitney RL-10 engine (1968): https://www.nasa.gov/rocket-engine-test-facility-apollo-era-testing/ · Source

Identity

Aliases
RL10RL-10Pratt & Whitney RL10Pratt & Whitney RL-10
Domains
spaceflight
Identity Level
family
Kind
liquid-rocket-engine
Name
RL10 family
Status
active

Details

Description
RL10 is a Pratt & Whitney-developed liquid-hydrogen/liquid-oxygen cryogenic upper-stage engine family first flown in 1963. NASA identifies the family as the propulsion of Centaur and later upper stages, with more than 500 RL10 engines flown; its expander cycle and evolved RL10A, RL10B, and RL10C models are represented by the child variants. Current RL10 production for Space Launch System missions is by L3Harris Technologies.
Developers
Manufacturers
Propellants
liquid hydrogenliquid oxygen
Rocket Specs
Cycle
expander cycle

Links

Official Url
https://www.nasa.gov/reference/space-launch-system-rl10-engine/

Assets & Meta

Creation Time
July 29, 2026 at 07:50:58 UTC
Updated Time
August 22, 2026 at 07:16:01 UTC
Image
Download

Other

Sources
  • Accessed Date
    2026-07-29
    Publisher
    NASA Technical Reports Server
    Title
    Cryogenic upper stage propulsion: RL10 and derivative engines
    Url
    https://ntrs.nasa.gov/citations/19910018888
  • Accessed Date
    2026-08-22
    Note
    NASA identifies RL10 as a Pratt & Whitney-developed engine first flown in 1963, reports more than 500 RL10 engines flown, identifies L3Harris Technologies as the current manufacturer for SLS missions, and describes RL10B-2, RL10C-2, and RL10C-3 roles.
    Publisher
    NASA
    Title
    Space Launch System RL10 Engine
    Url
    https://www.nasa.gov/reference/space-launch-system-rl10-engine/
  • Accessed Date
    2026-08-22
    Note
    NASA documents the RL10 liquid-hydrogen/liquid-oxygen expander cycle, its Centaur heritage, and the evolution from RL10A-3-3 through current RL10C models.
    Publisher
    NASA
    Title
    Original Cryogenic Engine Still Powers Exploration, Defense, Industry
    Url
    https://spinoff.nasa.gov/Spinoff2018/t_3.html