RL10-A-3
Pratt & Whitney RL10-A-3 is an early expander-cycle liquid-hydrogen/liquid-oxygen RL10 variant flown in six-engine clusters on Saturn I's S-IV upper stage. NASA's RL10 evolution table lists 15,000 lbf (66.72 kN) vacuum thrust and 429 s specific impulse for the A-3; exact Saturn I installations are preserved separately.
Identity
- Domains
- spaceflight
- Identity Level
- variant
- Kind
- liquid-rocket-engine
- Name
- RL10-A-3
- Status
- retired
Details
- Description
- Pratt & Whitney RL10-A-3 is an early expander-cycle liquid-hydrogen/liquid-oxygen RL10 variant flown in six-engine clusters on Saturn I's S-IV upper stage. NASA's RL10 evolution table lists 15,000 lbf (66.72 kN) vacuum thrust and 429 s specific impulse for the A-3; exact Saturn I installations are preserved separately.
- Developers
- Family
- Manufacturers
- Propellants
- liquid hydrogenliquid oxygen
- Rocket Specs
- Cycle
- expander cycle
- Vacuum Specific Impulse S
- 429
- Vacuum Thrust Kn
- 66.72
Links
Assets & Meta
- Creation Time
- July 29, 2026 at 09:02:47 UTC
- Updated Time
- August 22, 2026 at 11:03:50 UTC
Other
- Sources
- Accessed Date
- 2026-07-29
- Note
- Supports the legacy vehicle installation and the narrow canonical identity used for migration.
- Publisher
- Official vehicle or program source
- Title
- Saturn I Block II official vehicle reference
- Accessed Date
- 2026-07-29
- Publisher
- NASA Technical Reports Server
- Title
- Cryogenic upper stage propulsion: RL10 and derivative engines
- Accessed Date
- 2026-08-22
- Note
- NASA's RL10 evolution table lists the A-3 model at 15,000 lbf vacuum thrust and 429 s specific impulse, with June 1962 flight certification; 15,000 lbf is normalized to 66.72 kN.
- Publisher
- NASA Technical Reports Server
- Title
- Cryogenic upper stage propulsion: RL10 and derivative engines