| Abbreviation | Definition |
|---|---|
| ISPR | International Standard Payload Rack |
| ISR | Initial System Release |
| ISRO | Indian Space Research Organisation |
| ISS | Inertial Subsystem |
| ISS | Inertial Sub-System |
| ISS | Inhibit/override Summary Snapshot |
| ISS | Inhibit/Override Summary Snapshot Display |
| ISS | Installation Support Services |
| ISS | Instruction Summary Sheet |
| ISS | Integrated Support Stand |
| ISS | Integrated System Schematic |
| ISS | International Space Station |
| ISS | IRIS (Italian Research Interim Stage) Spinning Stage |
| ISTA | Intertank Structural Test Assembly |
| ISTB | Integrated Subsystem Test Bed |
| ISTF | Integrated System Test Flow |
| ISTP | International Solar Terrestrial Physics |
| ISU | Instrument Switching Unit |
| ISU | International System of Units |
| IT | Identification Transponder |