J-2
Rocketdyne's LOX/LH2 gas-generator upper-stage engine for Saturn IB and Saturn V. NASA documents J-2 as a restart-capable design used singly on S-IVB and in a five-engine S-II cluster; S-II application modifications removed restart hardware, so this model-level record does not imply identical restart behavior in every stage.
Identity
- Domains
- spaceflight
- Identity Level
- model
- Kind
- liquid-rocket-engine
- Name
- J-2
- Status
- retired
Details
- Description
- Rocketdyne's LOX/LH2 gas-generator upper-stage engine for Saturn IB and Saturn V. NASA documents J-2 as a restart-capable design used singly on S-IVB and in a five-engine S-II cluster; S-II application modifications removed restart hardware, so this model-level record does not imply identical restart behavior in every stage.
- Developers
- Dry Mass Kg
- 1837.0490985
- First Flight Date
- 1966-02-26
- Length M
- 3.3782
- Lineage
- Note
- NASA histories document RL10 technology informing J-2 development without making J-2 an RL10 family member.
- Related Propulsion System
- Relationship
- technology-derived-from
- Sources
- Accessed Date
- 2026-07-29
- Publisher
- NASA
- Title
- Glenn Impact on the Apollo Program
- Manufacturers
- Propellants
- liquid hydrogenliquid oxygen
- Rocket Specs
- Burn Time S
- 480
- Cycle
- gas generator
- Restartable
- Yes
- Vacuum Thrust Kn
- 1,023
Links
Assets & Meta
- Creation Time
- July 29, 2026 at 10:16:03 UTC
- Updated Time
- August 22, 2026 at 01:29:09 UTC
- Image
- Download
Other
- Sources
- Accessed Date
- 2026-07-29
- Publisher
- NASA
- Title
- Glenn Impact on the Apollo Program
- Accessed Date
- 2026-07-29
- Note
- NASA Science documents the Saturn V S-II second stage and its five J-2 engines.
- Publisher
- NASA Science
- Title
- Saturn V Stage 2
- 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 IB official vehicle reference
- Accessed Date
- 2026-08-14
- Note
- NASA documents the J-2 open-cycle gas-generator architecture, liquid oxygen/liquid hydrogen propellants, up-to-230,000-pound thrust, and Saturn V S-II/S-IVB applications.
- Publisher
- NASA Technical Reports Server
- Title
- Rocketdyne - J-2 Saturn V 2nd and 3rd Stage Engine
- Accessed Date
- 2026-08-15
- Note
- NASA records the first successful J-2 test flight on February 26, 1966.
- Publisher
- NASA
- Title
- Marshall at 65: The Foundational 1960s
- Accessed Date
- 2026-08-21
- Note
- NASA propulsion-system data lists the J-2 maximum length as 133 inches, engine mass as 4,050 lbm, restart capability, gas-generator cycle, and nominal 230,000 lbf vacuum thrust.
- Publisher
- NASA Technical Reports Server
- Title
- Propulsion System General Data