| Abbreviation | Definition |
|---|---|
| TTCA | Thrust Translation Controller Assembly |
| TTCV | Tracking Telemetry, Command, and Voice |
| TTE | Time To Event |
| TTEL | Tool and Test Equipment List |
| TTG | Time To Go |
| TTI | Transfer Trajectory Insertion |
| TTL | Transistor-Transistor Logic |
| TTLM | Through-the-Lens Light Metering |
| TTP | Time To Perigee |
| TTP | Transfer Trajectory Phase |
| TTSS | Technical Training Scheduling System - (USA) |
| TTSS | Training Tracking Scheduling System - (PGOC) |
| TTU | Timing Terminal Unit |
| TTU | Touch the Universe |
| TTV | Termination, Test, and Verification |
| TTY | TeleTYpe |
| TU | Technical Utilization |
| TU | Technology Utilization |
| TU | Transport Unit |
| TUL | Tula Peak, New Mexico, Spaceflight Tracking Data Network station |