RS-25
RS-25, formerly the Space Shuttle Main Engine, is the reusable staged-combustion LOX/LH2 engine adapted for NASA's Space Launch System core stage. NASA's SLS operating profile uses four engines at up to 109% rated power, approximately 512,000 lbf (2,279 kN) vacuum thrust; the canonical lifecycle remains active for the SLS program.
Identity
- Aliases
- Space Shuttle Main EngineSSME
- Domains
- spaceflight
- Identity Level
- model
- Kind
- liquid-rocket-engine
- Name
- RS-25
- Status
- active
Details
- Description
- RS-25, formerly the Space Shuttle Main Engine, is the reusable staged-combustion LOX/LH2 engine adapted for NASA's Space Launch System core stage. NASA's SLS operating profile uses four engines at up to 109% rated power, approximately 512,000 lbf (2,279 kN) vacuum thrust; the canonical lifecycle remains active for the SLS program.
- Developers
- First Flight Date
- 1981-04-12
- Manufacturers
- Propellants
- liquid hydrogenliquid oxygen
- Rocket Specs
- Cycle
- staged combustion
- Restartable
- Yes
- Vacuum Thrust Kn
- 2,279
Links
Assets & Meta
- Creation Time
- July 29, 2026 at 10:19:55 UTC
- Updated Time
- August 21, 2026 at 00:16:51 UTC
- Image
- Download
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
- Space Launch System Block 1B official vehicle reference
- Accessed Date
- 2026-07-29
- Publisher
- NASA
- Title
- Space Launch System RS-25 Core Stage Engine
- 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
- Space Launch System Block 2 official vehicle reference
- Accessed Date
- 2026-08-14
- Note
- NASA current SLS reference identifies four RS-25 core-stage engines, 109% rated-power operation, and approximately 512,300 pounds (2,279 kN) of thrust.
- Publisher
- NASA
- Title
- NASA Space Launch System Reference Guide Artemis II
- Accessed Date
- 2026-08-15
- Note
- NASA records the first Space Shuttle flight on April 12, 1981 using the reusable main engines now designated RS-25.
- Publisher
- NASA
- Title
- 40 Years Ago Columbia Takes Flight