Rocketdyne RS-25D
Exact historical Rocketdyne RS-25D staged-combustion LOX/LH2 variant used as the Space Shuttle Main Engine and retained in upgraded inventory for SLS. NASA's Shuttle-era operating profile used three engines at about 104.5% rated power, approximately 491,150 lbf (2,185 kN); lifecycle remains historical.
Identity
- Aliases
- RS-25DRS25DSpace Shuttle Main EngineSSME
- Domains
- spaceflight
- Identity Level
- variant
- Kind
- liquid-rocket-engine
- Name
- Rocketdyne RS-25D
- Status
- historical
Details
- Description
- Exact historical Rocketdyne RS-25D staged-combustion LOX/LH2 variant used as the Space Shuttle Main Engine and retained in upgraded inventory for SLS. NASA's Shuttle-era operating profile used three engines at about 104.5% rated power, approximately 491,150 lbf (2,185 kN); lifecycle remains historical.
- Family
- Manufacturers
- Propellants
- liquid oxygenliquid hydrogen
- Rocket Specs
- Cycle
- staged combustion
- Vacuum Thrust Kn
- 2,185
Links
Assets & Meta
- Creation Time
- August 6, 2026 at 23:31:13 UTC
- Updated Time
- August 23, 2026 at 11:39:09 UTC
- Image
- Download
Other
- Sources
- Accessed Date
- 2026-08-06
- Note
- NASA explicitly identifies RS-25D engines as the shuttle-era engines being moved for SLS use and records their proven shuttle role.
- Publisher
- NASA
- Title
- NASA Moves Shuttle Engines from Kennedy to Stennis
- Accessed Date
- 2026-08-06
- Note
- NASA documents the RS-25 core-stage engine lineage, shuttle inventory, and SLS adaptation while preserving the exact RS-25D historical boundary.
- Publisher
- NASA
- Title
- SLS (Space Launch System) RS-25 Core Stage Engine
- Accessed Date
- 2026-08-06
- Note
- NASA technical documentation names four RS-25D model engines in the SLS core-stage propulsion system.
- Publisher
- NASA Technical Reports Server
- Title
- Space Launch System Base Heating Test: Sub-Scale Rocket Engine/Motor Design, Development and Performance Analysis
- Accessed Date
- 2026-08-14
- Note
- NASA's SLS reference contrasts Shuttle operation at 104.5%, roughly 491,150 pounds (2,185 kN), with the later SLS 109% operating profile.
- Publisher
- NASA
- Title
- NASA's Space Launch System Reference Guide (Artemis II)