| Abbreviation | Definition |
|---|---|
| STS | Shuttle Test Station |
| STS | Space Transportation System (formal name for the Space Shuttle) |
| STS | Star Tracker Sensor |
| STS | Structural Transition Section |
| STSG | Shuttle Test Group |
| STSOPO | Shuttle Transportation Systems Operations Program Office |
| STSP | Solar Terrestrial Science Programme |
| STSR | System Test Summary Report |
| STSSM | Space Transportation System Service Module |
| STT | Spacelab Transfer Tunnel |
| STTE | Special to Type Test Equipment |
| STU | Shuttle Test Unit |
| STU | Special Test Unit |
| STU | Star Tracker Unit |
| STV | Space Transfer Vehicle |
| SU | Support Unit |
| SUB | Substitute |
| SUM | SOHO User's Manual |
| SUM | Summary |
| SUMC | Space Ultrareliable Modular Computer |