| Abbreviation | Definition |
|---|---|
| HYPACE | Hybrid Programmable Attitude Control Electronics |
| HZE | Highly Charged and Energetic Particles |
| HZE | Highly-charged and Energetic particle |
| I | Inertia |
| I | Injection |
| I | Inner |
| I | Iodine |
| I | Irradiated |
| I&C | Installation and Checkout |
| I&C/O | Installation And CheckOut |
| I&O | Inlet and Outlet |
| I&PS | Institutional and Program Support |
| I&R | Interchangeability And Replaceability |
| I&RS | Instrument and Range Safety |
| I&S | Interchangeability and Substitutability |
| I&T | Integration and Test |
| I&TRR | Integration and Test Readiness Review |
| I/A | Interface Adapter |
| I/C | InterCom |
| I/E | Input Electronics |