| Abbreviation | Definition |
|---|---|
| GWT | Ground Winds Tower |
| GYM | Guaymas, Mexico, Manned Space Flight Network station |
| GYP | Gyroscope Package |
| GYRO | Gyroscope |
| GYROA | Gyroscope A |
| GYROCOMP | GYROCOMPassing |
| H | Hazardous (Task Classification) |
| H | Head |
| H | Height (Altitude) |
| H | Henry |
| H | High |
| H | Horizontal |
| H | Hot |
| H | Hours |
| H' | Altitude Rate |
| H/E | Heat Exchanger |
| H/L | HardLine |
| H/O | HandOver |
| H/S | Heat Shield |
| H/SIR | Hardware/Software Integration Review |