| Abbreviation | Definition |
|---|---|
| ETA | External Tank Attachment |
| ETB | Equipment Transfer Bag |
| ETC | Earth Terrain Camera |
| ETC | Eastern Tracking Center, Greenbelt, Maryland, Spaceflight Tracking and Data Network site |
| ETC | Estimate To Completion |
| ETC | Experiment Test Cycle |
| ETCO | Equipment Transfer/Change Order |
| ETD | Electrical Terminal Distributor |
| ETD | Estimated Turnover Date |
| ETD | External Tank Door |
| ETHERNET | area network defined by ISO 802.3 |
| ETI | Elapsed Time Indicator |
| ETLOW | External Tank Lift-Off Weight |
| ETM | Elapsed Time Meter |
| ETP | Equipment Test Plan |
| ETROD | Eastern Test Range Operations Directive |
| ETRS | European Terrestrial Reference System |
| ETS | Electrical Test Set |
| ETS | Energy Transfer System |
| ETS | Estimated Time of Separation |