| Abbreviation | Definition |
|---|---|
| SL-SS | Spacelab Subsystems |
| SL-SSS | Spacelab Subsystem(s) Segment |
| SLT | ERNO Spacelab Technology |
| SLV | Space Launch Vehicle |
| SLW | straight-line wavelength |
| SM | Science Mission |
| SM | Secondary Mirror |
| SM | Service Model |
| SM | Service Module ( Apollo) |
| SM | Short Module |
| SM | Shuttle Management |
| SM | Shuttle Management (KSC) |
| SM | Soft Manual |
| SM | Stable Member |
| SM | Structural Model |
| SM | Support Module |
| SM | Systems Management |
| SM&S | Systems Management and Sequencing |
| SM/PM | System Management/Performance Monitor |
| SMA | Science Monitoring Area |