| Abbreviation | Definition |
|---|---|
| S | Stere |
| S&A | Safe and Arm (Device) |
| S&A | Science and Application |
| S&AD | Science and Applications Directorate |
| S&E | Science and Engineering (MSFC Directorate) |
| S&H | Safety and Health |
| S&MA | Safety and Mission Assurance |
| S/A | Safe and Arm |
| S/A | Scheduled/Actual |
| S/A | Site Activation |
| S/A | Spacecraft Adapter |
| S/A | Subassembly |
| S/A | Sub-Assembly |
| S/AC | Stabilization/Attitude Control |
| S/B | Standby |
| S/C | Sensor/Controller |
| S/C | Signal Conditioner |
| S/C | Software Contractor |
| S/C | Spacecraft |
| S/C | Splitter/Combiner |