| Abbreviation | Definition |
|---|---|
| INH | Inhibit |
| INIT | Initialization |
| INIT | Initiate |
| INJ | Inject |
| INL | Inlet |
| INOP | Inoperative |
| INP | Input |
| INR | INertial Reference |
| INRTL | INeRTiaL |
| INRTLVEL | INeRTiaL VELocity |
| INS | INSertion burn |
| INSAT | Indian National SATellite |
| INSL | INSuLate |
| INSP | INSPect |
| INSPEX | INdonesia SPace EXperiment |
| INSPIRE | Interactive NASA Space Physics Ionosphere Radio Experiment |
| INSRP | Interagency Network Safety Review Panel |
| INST | INSTrument |
| INST/COMM | INSTrumentation and COMMunication |
| INSTL | INSTalL |