| Acronym | Meaning |
| SRB | Solid Rocket Booster |
| SRM | Solid Rocket Motor |
| SSBUV | Shuttle Solar Backscatter Ultraviolet Experiment |
| SSCE | Solid Surface Combustion Experiment |
| SSF | Space Station Freedom |
| SSI | Solid-State Imager / Space Studies Institut |
| SSME | Space Shuttle Main Engine |
| SSO | Spurious Shut-off |
| SSPF | Space Station Processing Facility |
| SSPO | Space Shuttle Program Office |
| SSPS | Sky Survey Prototype System |
| SSRMS | Space Station Remote Manipulator System |
| SSRT | Single Stage Rocket Technology |
| SSRV | Solar-Sail Race Vehicle |
| SST | Spectroscopic Survey Telescope / SuperSonic Transport |
| SSTO | Single Stage To Orbit |
| STARCAL | Star Calibration |
| STC | Stennis Test Center |
| STC | SHAPE Technical Center |
| STDCE | Surface Tension Driven Convection Experment |
| STIKSCAT | Stick Scatterometer |
| STIS | Space Telescope Imaging Spectrometer |
| STS | Shuttle Transport System / Space Transportation System |
| STSCI | Space Telescope Science Institute |
| STSDAS | Space Telescope Science Data Analysis System |
| SUSIM | Solar Ultraviolet Spectral Irradiance Monitor |
| SWAN | Solar Wind Anisotropy Experiment |
| SWAS | Submillimeter Wave Astronomy Satellite |
| SWF | ShortWave Fading |
| SWLC | Salt Water Leak Check |
| TAI | International Atomic Time |
| TAL | Transatlantic Abort Landing |
| TAU | Thousand Astronomical Unit |
| TCM | Trajectory Control Maneuver |
| TCS | Thermal Control System |
| TDRS | Tracking And Data Relay Satellite |
| TDRSS | Tracking And Data Relay Satellite System |
| TDT | Terrestrial Dynamic Time |
| TEA | Torque Equilibrium Attitude |
| TES | Thermal Emission Spectrometer |
| THIR | Temperature/Humidity Infrared Radiometer |
| TIG | Time Of (until) Ignition |
| TIROS | Television InfraRed Observation Satellite |
| TKSC | Tsukuba Space Center |
| TM | Thematic Mapper |
| TOMS | Total Ozone Mapping Spectrometer |
| TOPEX | Ocean Topography Experiment |
| TOPS | Toward Other Planetary Systems |
| TOS | Transfer Orbit Stage |
| TPCE | Tank Pressure Control Experiment |