| Term | Definition / Meaning / Stand for |
| SR |
Safety Regulations |
| SOF |
Safety of Flight |
| SOC |
Satellite Operations Center |
| SPS |
Satellite Positioning System |
| SAR |
Search and Rescue |
| SIC |
Second In Command |
| SAHR |
Semi-Active Homing Radar |
| SM |
Service Module |
| SOA |
Service-Oriented Architecture |
| STOVL |
Short Takeoff and Vertical Landing |
| SIM |
Simulation |
| SA |
Situational Awareness |
| SEP |
Solar Electric Propulsion |
| SP |
Solar Panel |
| SD |
Space Debris |
| SDA |
Space Domain Awareness |
| SEA |
Space Environment Analysis |
| SES |
Space Exploration System |
| SMD |
Space Mission Directorate |
| SPN |
Space Network |
| SPV |
Space Propulsion Vehicle |
| SSP |
Space Shuttle Program |
| SSA |
Space Situational Awareness |
| SS |
Space Station |
| SSC |
Space Surveillance Center |
| SSI |
Space Systems Integration |
| ST |
Space Technology |
| STP |
Space Test Program |
| SMC |
Space and Missile Center |
| SCS |
Spacecraft Control System |
| SCE |
Spacecraft Electrical System |
| SCG |
Spacecraft Guidance |
| SCI |
Spacecraft Instrumentation |
| SPAR |
Spacecraft Parts and Repair |
| SPA |
Spacecraft Power Analysis |
| SPC |
Spacecraft Power Conditioning |
| SPE |
Spacecraft Power Electronics |
| SPF |
Spacecraft Propulsion Function |
| SRC |
Spacecraft Recovery Capsule |
| SSU |
Spacecraft Support Unit |
| SC |
Spacecraft |
| SPO |
Special Operations |
| SG |
Specific Gravity |
| SPD |
Speed |
| SBU |
Standard Bus Unit |
| SMP |
Standard Maintenance Procedure |
| STA |
Stationary Approach |
| SMA |
Structural Mechanics Analysis |
| SAB |
Supersonic Air Breather |
| SERP |
Supersonic Engine Research Program |
| SSG |
Supersonic Glide |
| SST |
Supersonic Transport |
| SMG |
Surface Movement Guidance |
| SAM |
Surface-to-Air Missile |
| SAF |
Sustainable Aviation Fuel |
| SRT |
Synthetic Radar Target |
| SE |
Systems Engineering |
| SIL |
Systems Integration Laboratory |
| SRO |
Systems Readiness Overview |
| SACA |
Safety Assessment of Community Aircraft |
| SKPI |
Safety Key Performance Indicator |
| SMS |
Safety Management System |
| SBA |
Santa Barbara Airport |
| SBAS |
Satellite-Based Augmentation System |
| SATCOM |
Satellite Communications |
| SECO |
Second-stage Engine Cut-Off |
| SSR |
Secondary Surveillance Radar |
| SELCAL |
Selective Calling System |
| SCCM |
senior cabin crew member |
| SN |
Serial Number |