| Acronym | Meaning |
 | IDWA | Interdivisional Work Authorization |
 | IE | Industrial Engineering |
 | IEA | Integrated Electronic Assembly |
 | IEA | Integrated Electronic Assembly |
 | IECS | Igloo Environment Control Subsystem |
 | IED | Interacting Equipment Documents |
 | IEF | Isoelectric Focusing |
 | IEP | Instantaneous Effective Photo Cathodes |
 | IF | Integration Facility |
 | IFA | In-FlightAnalyses |
 | IFASC | Integrated Functions Assessment Steering Committ |
 | IFB | Invitation For Bid |
 | IFM | In-FlightMaintenance |
 | IFO | Information Systems Office |
 | IFOT | In-Flight Operations And Training |
 | IFR | Instrument Flight Rules |
 | IFRU | In-Flight Replacement Unit |
 | IFT | In-Flight Test |
 | IFTM | In-Flight Test Maintenance |
 | IFTS | In-Flight Test System |
 | IFU | InterfaceUnit |
 | IG | Igloo |
 | IGA | Inner Gimbal Angle |
 | IGAX | Inner Gimbal Axis |
 | IGDS | Iodine Generating And Dispensing SYstem |
 | IGM | Interactive Guidance Mode |
 | IGN | Ignition |
 | IGOR | Intercept Ground OPtical Recorder |
 | IGS | Inertial Guidance System |
 | IGSE | In-Space Ground SUPPort Equipment |
 | IGV | Inlet GUide Valve/Vanes |
 | IH/SR | Integration Hardware And Software Review |
 | IHP | Indicated Horsepower |
 | IHTV | Interim Hypersonics Test Vehicle |
 | IHX | Interloop Heat Exchanger |
 | IIS | InsPection Item Sheet |
 | IIS | Joint Integrated Simulation |
 | IITCS | Igloo Internal Thermal Control Section |
 | ILA | Instrument Landing Approach |
 | ILC | Initial Launch Capability |
 | ILC | International Latex Corporation |
 | ILLUM | Illuminate |
 | ILP | IntegratedLogistics Panel |
 | ILS | InstrumentLanding System |
 | ILS | IntegratedLogistics Support |
 | ILS | IntegratedLogistics System |
 | ILS/LAR | IntegratedLogistics System And Logistics Assess |
 | ILS/LAR | Review |
 | ILSSE | Integrated Life Science Shuttle Experiments |
 | IMBLMS | Integrated Medical Behavioral Laboratory Measuremen |