Aerojet YLR-91-AJ-7
Historical Aerojet-General YLR-91-AJ-7 storable bipropellant second-stage engine for the Titan II Gemini Launch Vehicle. NASA identifies the YLR-91-AJ-7 as the GLV Stage II engine, and NASA dates Gemini I's first production Titan II launch to 1964-04-08; this record uses that date as the engine assembly's first flight. NASA's Gemini-Titan table lists one YLR-91-AJ-7 engine at 100,000 lbf (about 444.8 kN) sea-level thrust, using UDMH and nitrogen tetroxide as the single second-stage powerplant.
Identity
- Aliases
- YLR91-AJ-7
- Domains
- spaceflight
- Identity Level
- variant
- Kind
- liquid-rocket-engine
- Name
- Aerojet YLR-91-AJ-7
- Status
- historical
Details
- Description
- Historical Aerojet-General YLR-91-AJ-7 storable bipropellant second-stage engine for the Titan II Gemini Launch Vehicle. NASA identifies the YLR-91-AJ-7 as the GLV Stage II engine, and NASA dates Gemini I's first production Titan II launch to 1964-04-08; this record uses that date as the engine assembly's first flight. NASA's Gemini-Titan table lists one YLR-91-AJ-7 engine at 100,000 lbf (about 444.8 kN) sea-level thrust, using UDMH and nitrogen tetroxide as the single second-stage powerplant.
- Developers
- First Flight Date
- 1964-04-08
- Manufacturers
- Propellants
- UDMHnitrogen tetroxide
- Rocket Specs
- Sea Level Thrust Kn
- 444.8
Links
- Official Url
- https://sma.nasa.gov/LaunchVehicle/titanglv.html
Assets & Meta
- Creation Time
- July 29, 2026 at 08:15:42 UTC
- Updated Time
- August 22, 2026 at 11:01:30 UTC
Other
- Sources
- Accessed Date
- 2026-08-14
- Note
- NASA's Titan II Gemini vehicle table identifies one Aerojet-General YLR-91-AJ-7 second-stage engine, UDMH/N2O4 propellants, and 444,800 newtons thrust.
- Publisher
- NASA
- Title
- NASA Historical Data Book, Volume II
- Accessed Date
- 2026-08-14
- Note
- NASA's technical report describes the Titan II Gemini YLR91-AJ-7 second-stage engine and its qualification as part of the modified Titan II launch vehicle.
- Publisher
- NASA Technical Reports Server
- Title
- Aerospace Report on Gemini Launch Vehicle Propulsion
- Accessed Date
- 2026-07-29
- Publisher
- NASA Safety and Mission Assurance
- Title
- Titan II Gemini Launch Vehicle
- Accessed Date
- 2026-08-21
- Note
- NASA identifies Gemini I as the first production Gemini spacecraft and Titan II launch vehicle, with liftoff on 1964-04-08; this supports the engine assembly first-flight date.
- Publisher
- NASA
- Title
- Gemini I