| I | in phase |
| I | inertia |
| I | integer valve |
| I | irradiated |
| I&C | installation and checkout |
| I&C | instrumentation and communication |
| I&C | integration and checkout |
| I&C/O | installation and checkout |
| I&ES | information and electronics system |
| I&O | inlet and outlet |
| I&Q | in phase and quadrature |
| I&R | inspect and review |
| I&R | interchangeability and replaceability |
| I&RS | instrumentation and range safety |
| I&S | interchangeability and substitutability |
| I&T | integration and test |
| I-load | initial load |
| I-load | initialization load |
| I/C | intercom |
| I/F | interface |
| I/FU | interface unit |
| I/O | input/output |
| I/OB | input/output bus |
| I/OC | input/output controller |
| I/OMI | integration, operations, and maintenance instruction |
| I/OP | inboard/outboard profile |
| I/OT | input/output test |
| I/OU | input/output unit |
| I/P | impact predictor |
| I/P | in progress |
| I/Q | in phase/quadrature |
| I/S | installation of systems |
| I/T | intertank |
| I/U | instrumentation unit |
| I/V | inlet valve |
| I/W | in work |
| I3L | isoplanar integrated injection logic |
| IA | implementation agency |
| IA | input axis |
| IA | interface agreement |
| IA | inverter assembly |
| IA | issuing agency |
| IA&T | integration, assembly, and test |
| IAA | International Aerospace Abstracts |
| IAB | IUS Assembly Building |
| IACO | installation, assembly, and checkout |
| IACS | inertial attitude control system |
| IAD | interface agreement document |
| IAD | interface analysis document |
| IAF | interactive facility |
| IAH | interface attachment hardware |
| IAL | immediate action letter |
| IAL | international algebraic language |
| IAM | International Association of Machinists |
| IAM | information asset management |
| IAN | institutional area network |
| IAPU | improved auxiliary power unit |
| IAS | Institute of Aeronautical Sciences |
| IAS | impact assessment sheet |
| IAS | indicated airspeed |
| IAS | integrated avionics subsystem |
| IASS | inverter/ATCS support structure |
| IAT | integrated avionics test |
| IAV | inventory adjustment voucher |
| IAW | in accordance with |
| IB | inboard |
| IB | inert building |
| IB | inner button |
| IB | instruction book |
| IBC | impurity-band conductor |
| IBEW | International Brotherhood of Electrical Workers |
| IBF | internally blown flap |
| IBM | International Business Machines |
| IBR | implementation baseline review |
| IBSS | Infrared Background Signature Survey |
| IBT | International Brotherhood of Teamsters |
| IC | IOC chamber |
| IC | incremental cost |
| IC | inertial component |
| IC | information center |
| IC | initial condition |
| IC | integrated circuit |
| IC | integration cell |
| IC | intercom |
| IC | intercommunications |
| IC | intercomputer |
| IC | intercomputer communication |
| IC | interim change |
| IC | internal combustion |
| IC/ES | intercommunication/emergency station |
| ICA | intelligent communicating agent |
| ICA | interim change analysis |
| ICA | item change analysis |
| ICAAD | interactive computer-aided analysis and design |
| ICAI | intelligent CAI |
| ICAM | integrated computer-aided manufacturing |
| ICAO | International Civil Aviation Organization |
| ICAPC | increased-capability adaptive payload carrier |
| ICAR | initiated corrective action report |
| ICAR | investigation and corrective action report |
| ICB | interim change bulletin |
| ICB | interrupt control block |
| ICBC | IMAX cargo bay camera |
| ICBM | intercontinental ballistic missile |
| ICC | Interstate Commerce Commission |
| ICC | intercomputer channel |
| ICC | intercomputer communication |
| ICC | interface control chart |
| ICC | interface control contractor |
| ICCD | intensified CCD |
| ICCP | interface coordination and control procedure |
| ICCWG | Intercenter Communication Working Group |
| ICD | interface control document |
| ICD | interface control documentation |
| ICD | interface control drawing |
| ICDR | incremental critical design review |
| ICDS | interface control document schedule |
| ICDU | inertial coupling data unit |
| ICE | input control element |
| ICE | instrument checkout equipment |
| ICE | instrument/communication equipment |
| ICE | instrumentation/communication equipment |
| ICF | interface control function |
| ICG | in-flight coverall garment |
| ICHA | integrated cargo hazard assessment |
| ICI | interim configuration inspection |
| ICL | interface control layout |
| ICM | instrumentation and communication monitor |
| ICM | integrated cost module |
| ICMS | indirect cost management system |
| ICMT | intercontract material transfer |
| ICN | intercomputer network |
| ICN | interface change notice |
| ICO | integrated checkout |
| ICO | integrated-communication officer |
| ICP | ICS control program |
| ICP | indicator control panel |
| ICP | interface change proposal |
| ICP | interface control panel |
| ICP | inventory control point |
| ICR | inductance, capacitance, and resistance |
| ICR | instruction change request |
| ICR | interface compatibility record |
| ICRB | Interface Change Review Board |
| ICRP | International Council on Radiation Protection |
| ICS | instrumentation control system |
| ICS | intercommunication system |
| ICS | interface control specification |
| ICS | interphone control station |
| ICS | interpretive computer simulator |
| ICSU | International Council of Scientific Unions |
| ICT | influence coefficient test |
| ICT | interface control tooling |
| ICTC | inertial component temperature controller |
| ICTE | inertial component test equipment |
| ICU | in-flight calibration unit |
| ICU | interface control unit |
| ICW | interrupted continuous wave |
| ICWG | Interface Control Working Group |
| ID | identification |
| ID | identification data |
| ID | inside diameter |
| ID | integrated diagnostic |
| ID | interactive discrimination |
| ID | interface device |
| ID | interface document |
| ID&C | integrated displays and controls |
| ID&CA | inverter distribution and control assembly |
| ID&CS | ID&C subsystem |
| ID&D | inspection damage and discrepancy |
| IDA | integrated display assembly |
| IDA | interface definition agreement |
| IDA | intermediate data array |
| IDAC | integrated digital-analog converter |
| IDAR | interim data assessment review |
| IDAS | integrated data acquisition system |
| IDB | in-suit drink bag |
| IDBMS | integrated data base management system |
| IDC | IMBLMS digital computer |
| IDC | integrated displays and controls |
| IDC | interface document control |
| IDCA | inverter distribution and control assembly |
| IDCP | interdivision change proposal |
| IDD | IGS data denial |
| IDD | integrated data denial |
| IDD | interface definition document |
| IDD | interface description document |
| IDD | interface design document |
| IDE | initial design evaluation |
| IDE | integrated design environment |
| IDE | interactive development environment |
| IDEAS | initial design and evaluation analysis system |
| IDEAS2 | independent design and evaluation of advanced spacecraft |
| IDEF | ICAM definition |
| IDEP | interservice data exchange program |
| IDG | integrated drive generator |
| IDI | instrumentation data item |
| IDL | indentured drawing list |
| IDMM | Intermediate and Depot Maintenance Manual |
| IDMRD | intermediate and depot maintenance requirements document |
| IDMRS | intermediate depot maintenance requirements |
| IDMS | information and data management system |
| IDO | interdivisional operation |
| IDOS | integrated display operating system |
| IDOT | instrument digital on-line transcriber |
| IDP | I-load data pack |
| IDP | integrated data processing |
| IDP | interface digital processor |
| IDR | initial design review |
| IDR | interim data review |
| IDR | interim design review |
| IDR | interim discrepancy report |
| IDR | intermediate design review |
| IDRA | interdivision revision authorization |
| IDRD | information definition requirements document |
| IDRD | internal data requirement description |
| IDS | I-load data set |
| IDS | information data system |
| IDS | integrated defense simulator |
| IDS | integrated design support |
| IDS | integrated design system |
| IDS | integrated display system |
| IDS | interface data sheet |
| IDS | item description sheet |
| IDSD | Institutional Data System Division (JSC) |
| IDSNET | integrated defense simulator network |
| IDSNET | integrated defense system network |
| IDSO | interdivisional sales order |
| IDSR | initial design status review |
| IDSR | interdivisional support request |
| IDSS | integrated design support system |
| IDSS | integrated diagnostic support system |
| IDT | I-load data tape |
| IDT | image detector tube |
| IDT | image dissector tube |
| IDTA | interdivisional technical agreement |
| IDU | interface demonstration unit |
| IDWA | interdivisional work authorization |
| IEA | integrated electronic assembly |
| IECM | induced-environment contamination monitor |
| IECO | inboard engine cutoff |
| IECS | igloo environment control subsystem |
| IED | interacting equipment document |
| IEEE | International Electrical and Electronic Engineers |
| IEEP | incapacitated emergency egress practice |
| IEF | isoelectric focusing |
| IEFT | integrated experiment functional test |
| IEIWG | International Element Interface Working Group |
| IEMC | intrasystem electromagnetic compatibility |
| IEMCAP | Intrasystem Electromagnetic Compatibility Computer Analysis Program |
| IES | information extraction system |
| IESD | Instrumentation and Electronic Systems Division (JSC) |
| IF | integration facility |
| IF | interface |
| IF | intermediate frequency |
| IF | internal fault |
| IF/FDM | intermediate frequency/frequency division multiplexer |
| IFA | in-flight analysis |
| IFA | interface functional analysis |
| IFASC | Integrated Functions Assessment Steering Committee |
| IFB | invitation for bid |
| IFCG | Interface Control Group |
| IFDL | interfacility data link |
| IFE | industrial furnished equipment |
| IFE | isoelectric focusing experiment |
| IFF | identification, friend or foe |
| IFFN | identification, friend, foe, neutral |
| IFM | in-flight maintenance |
| IFO | Information Systems Office |
| IFOT | in-flight operations and training |
| IFOV | instantaneous field of view |
| IFOV | instrument field of view |
| IFR | instrument flight rule |
| IFRU | in-flight replaceable unit |
| IFS | impact and flotation system |
| IFS | integrated FEP simulator |
| IFS | integrated flight simulator |
| IFS | interface specification |
| IFT | in-flight test |
| IFT | interface tool |
| IFTD | interface terminal distributor |
| IFTE | intermediate forward test equipment |
| IFTM | in-flight test and maintenance |
| IFTS | in-flight test system |
| IFU | interface unit |
| IG | inertial guidance |
| IG | inner gimbal |
| IG | instrument ground |
| IG | instrumentation group |
| IG | internal guidance |
| IGA | inner gimbal angle |
| IGAX | inner gimbal axis |
| IGC | interactive gaming center |
| IGDR | interim GDR |
| IGDR | interior geophysical data record |
| IGDS | interactive graphic design system |
| IGDS | iodine generating and dispensing system |
| IGE | image generating equipment |
| IGE | instrumentation ground equipment |
| IGES | initial graphic exchange specification |
| IGM | interactive guidance mode |
| IGM | iterative guidance mode |
| IGN&C | integrated guidance, navigation, and control |
| IGOR | intercept ground optical recorder |
| IGOS | interactive graphic orbit system |
| IGS | IONDS global segment |
| IGS | inertial guidance system |
| IGS | intergimbal assembly |
| IGSE | in-space ground support equipment |
| IGSE | instrument ground support equipment |
| IGV | inlet guide valve |
| IGV | inlet guide vane |
| IGY | international geophysical year |
| IH/SR | integrated hardware/software review |
| IHA | interface hazard analysis |
| IHP | indicated horsepower |
| IHSR | integrated hardware/software review |
| IHTV | interim hypersonic test vehicle |
| IHX | interloop heat exchanger |
| II | implementing instruction |
| IIOP | in-orbit plane |
| IIS | inspection item sheet |
| IIS | interface identification sheet |
| IISS | integrated information support system |
| IITCS | igloo internal thermal control section |
| IK | inner keel |
| IL | internal letter |
| ILA | instrument landing approach |
| ILAS | instrument landing approach system |
| ILC | International Latex Company |
| ILC | initial launch capability |
| ILCCS | integrated launch checkout and control system |
| ILMF | intermediate-level maintenance facility |
| ILO | integrated logistics operations |
| ILP | Integrated Logistics Panel |
| ILRV | integral launch and reentry vehicle |
| ILS | instrument landing system |
| ILS | integrated logistics support |
| ILS | integrated logistics system |
| ILS/LAR | integrated logistics system and logistics a |
| ILSA | integrated logistics support analysis |
| ILSC | integrated logistics support concept |
| ILSCP | integrated logistics support concept plan |
| ILSIM | integration of lethality studies into model |
| ILSMT | Integrated Logistics Support Management Team |
| ILSP | integrated logistics support plan |
| ILSSE | integrated life science Shuttle experiment |
| ILSWG | Integrated Logistics Support Working Group |
| ILT/RT | imprecisely located target/relocatable target |
| IM | information memory |
| IM | infrastructure module |
| IM | integration management |
| IM | interface module |
| IM | intermediate moisture |
| IM | intermodulation |
| IMADS | information management assimilation and delivery system |
| IMAS | institutional management accounting system |
| IMBLMS | integrated medical/behavioral laboratory measurement |
| IMC | image motion compensation |
| IMCC | Integrated Mission Control Center |
| IMCP | integrated monitor and control panel |
| IMCR | integrated master control record |
| IMDB | integrated maintenance data base |
| IMDS | integrated monitoring and diagnostics system |
| IMF | inventory master file |
| IMIC | Integrated Management Information Center |
| IMIC | integrated management information computer |
| IMIP | Industrial Modernization Incentive Program |
| IML | inner mold line |
| IML | inside mold line |
| IMLEO | initial mass in low Earth orbit |
| IMO | Integration Management Office |
| IMP | inflatable micrometeoroid paraglider |
| IMP | information management plan |
| IMP | initial memory protection |
| IMP | interplanetary monitoring platform |
| IMP | inventory management plan |
| IMPACT | integrated material productivity action |
| IMRB | interim mission reconfiguration base |
| IMRO | inspection, modification, and repair order |
| IMS | information management system |
| IMS | inhibit main store |
| IMS | interplanetary monitor satellite |
| IMS | inventory management system |
| IMSS | in-flight medical supply system |
| IMST | integrated mission simulation test |
| IMTF | integrated manufacturing test facility |
| IMU | inertial measurement unit |
| IMUGSE | IMU ground support equipment |
| IMUPLM | inertial measurement unit prelaunch monitor |
| IMW | intelligent machining work station |
| IN | Information Systems Directorate (KSC) |
| INBIT | input bit |
| INC | installation notice card |
| INC | installation notification certificate |
| INCO | instrumentation and communication officer |
| INDAT | incoming data |
| INITCO | initialization and checkout |
| INR | inertial reference |
| INS | inertial navigation system |
| INSAT | India communications satellite |
| INT | integrated test |
| INTASAT | Instituto Nacional De Tecnica Aerospacial |
| INTC/O | integrated checkout |
| INTELSAT | International Telecommunications Satellite |
| INTF | interim national test facility (CSOC location) |
| IO | industral operations |
| IOA | input, output, or assembly |
| IOA | input/output adapter |
| IOB | input/output box |
| IOB | input/output buffer |
| IOB | input/output bus |
| IOBPS | input/output box and peripheral simulator |
| IOC | indirect operating cost |
| IOC | initial operational capability |
| IOC | input/output controller |
| IOC | integrated operations configuration |
| IOC | item of concern |
| IOCP | ITS on-board computer program |
| IOCU | input/output control unit |
| IOD | initial orbit determination |
| IOE | input/output error (log table) |
| IOF | initial operational flight |
| IOHA | integrated operating hazard analysis |
| IOL | interoffice letter |
| IOM | input/output module |
| IONDS | integrated operational nuclear detection system |
| IONDS | integrated operational nuclear detonation system |
| IOP | input/output part |
| IOP | input/output processor |
| IOPL | integrated open-problem list |
| IOPT | input/output parameter table |
| IOQE | input/output queue element |
| IORL | input/output requirements language |
| IORTD | input/output relationships and timing diagram |
| IOS | Indian Ocean ship |
| IOS | initial operational system |
| IOS | input/output supervisor |
| IOS | instructor operator station |
| IOSC | integrated operations support complex (VLS) |
| IOT&E | initial operational test and evaluation |
| IOT&E | integration operational test and evaluation |
| IOU | input/output unit |
| IP | identification of position |
| IP | impact point |
| IP | in plant |
| IP | industrial preparedness |
| IP | inertial processing |
| IP | initial point |
| IP | instructor pilot |
| IP | instrument payload |
| IP | instrument processor |
| IP | instrumentation of pulse code modulation master unit |
| IP | interfacing processor |
| IP | intermediate pallet |
| IP | intermediate pressure |
| IP | iron pipe |
| IPA | industrial preparedness action |
| IPA | intermediate-power amplifier |
| IPACS | integrated power and attitude control system |
| IPAD | integrated program for aerospace vehicle design |
| IPAR | irregular parts authorization request |
| IPAS | integrated problem assessment system |
| IPB | illuminated push button |
| IPB | illustrated parts breakdown |
| IPC | integrated procurement control |
| IPC | intermittent positive control |
| IPCL | instrument program and component list |
| IPCL | instrumentation program and components list |
| IPD | Information Processing Division |
| IPDR | incremental preliminary design review |
| IPE | industrial plant equipment |
| IPF | IUS Processing Facility |
| IPL | indentured parts list |
| IPL | initial program load |
| IPLC | initial program load complete |
| IPLS | initial program load start |
| IPM | integration program manager |
| IPMS | inertial performance measurement system |
| IPP | individual program plan |
| IPP | industrial preparedness plan |
| IPPB | illustrated provisioning parts breakdown |
| IPR | ice-point reference |
| IPR | in-process review |
| IPR | interim problem report |
| IPS | information processing system |
| IPS | instrument pointing system (subsystem) |
| IPS | instrumentation power system (subsystem) |
| IPS | integrated propulsion system |
| IPS | international pipe standard |
| IPS | inverter power supply |
| IPS | invoice processing system |
| IPSL | interface problem status log |
| IPSS | integrated parts statusing system |
| IPSS | integrated project scheduling system |
| IPT | in-plant transporter |
| IPT | internal parameter table |
| IPT | internal pipe thread |
| IPT | international pipe thread |
| IPTCS | igloo passive thermal control section |
| IPTR | in-process technical review |
| IPWG | Integrated Project Working Group |
| IQSY | international quiet sun year |
| IQT | initial qualification training |
| IR | inclination of the ascending return |
| IR | infrared |
| IR | inner roll |
| IR | inside radius |
| IR | interchangeability and replaceability |
| IR | international rendezvous |
| IR | interrogator-responder |
| IR&D | independent research and development |
| IRAM | input random access memory |
| IRAMS | inertial reference alignment monitor system |
| IRAN | inspection and repairs as necessary |
| IRANSAT | Iranian government communications satellite |
| IRAS | infrared astronomical satellite |
| IRBM | intermediate-range ballistic missile |
| IRBS | infrared background sensor |
| IRBS | intermediate-range ballistic system |
| IRBS | intermediate-range booster system |
| IRCFE | infrared communications flight experiment |
| IRCS | integrated resource control system |
| IRD | information requirements description |
| IRD | information requirements document |
| IRD | initiating reference document |
| IRD | integration requirements document |
| IRD | interface requirements document |
| IRDS | information resource dictionary system |
| IRDTS | ITS RF and digital test set |
| IRE | Institute of Radio Engineers |
| IRG | inertial rate gyro |
| IRIG | Interrange Instrumentation Group |
| IRIG | inertial rate integrating gyroscope |
| IRIG | inertial reference integrating gyroscope |
| IRIS | Italian research interim stage |
| IRIS | infrared instrumentation system |
| IRL | initiating reference list |
| IRL | interface requirements list |
| IRM | information resource management |
| IRM | integrated range mission |
| IRME | initiator resistance measuring equipment |
| IRN | interface revision notice |
| IRN | interim revision notice |
| IRP | inertial reference package |
| IRR | independent readiness review |
| IRR | initial requirements review |
| IRR | inspection rejection report |
| IRR | integral rocket ramjet |
| IRR | integrated readiness review |
| IRR | interface requirements review |
| IRS | interface requirements specification |
| IRST | infrared search track |
| IRTCM | integrated real-time contamination monitor |
| IRU | IVA replaceable unit |
| IRU | inertial reference unit |
| IS | installation support |
| IS | instrumentation system |
| IS | integrated satellite |
| IS | interconnecting station |
| ISA | inertial sensor assembly |
| ISA | instruction set architecture |
| ISA | instructional systems approach |
| ISA | interim stowage assembly |
| ISAR | inverse synthetic-aperture radar |
| ISATS | integration spacecraft automated test system |
| ISB | independent side band |
| ISC | Information Systems Center |
| ISC | industrial support contractor |
| ISCCB | Internal Software Change Control Board |
| ISCM | initial software configuration map |
| ISD | inspection supervision disposition |
| ISD | instruction sequence diagram |
| ISD | instructional systems design |
| ISD | instructional systems development (USAF) |
| ISEE | international sun-Earth explorer |
| ISF | industrial space facility |
| ISHA | integrated system hazard analysis |
| ISI | initial systems installation |
| ISI | instrumentation support instruction |
| ISIL | interim support items list |
| ISIS | integrated safety information system |
| ISL | inertial systems laboratory |
| ISLM | integration shop and lab manager |
| ISM | image steering mirror |
| ISMRB | Information Systems Management Review Board |
| ISMS | interactive supply management system |
| ISN | internal statement number |
| ISO | International Standardization Organization |
| ISP | Integrated Space Plan |
| ISP | instrumentation support plan |
| ISP | integrated support plan |
| ISPF | interactive system productive facility |
| ISPG | Institutional Support Planning Group |
| ISR | industrial security regulation |
| ISR | initial system release |
| ISR | integrated safety review |
| ISR | interim shop release |
| ISR | interim system review |
| ISR | interrupt service routine |
| ISRB | Integrated System Review Board |
| ISS | inertial subsystem |
| ISS | information subsystem |
| ISS | installation support services |
| ISS | instruction summary sheet |
| ISS | integrated scheduling system |
| ISS | integrated system schematic |
| ISS | international space station |
| ISSA | integrated software safety analysis |
| ISSL | initial spares support list |
| ISSO | Information Systems Security Office |
| IST | initial system test |
| IST | instrumentation support team |
| IST | integrated systems test |
| ISTA | intertank structural test assembly |
| ISTB | integrated subsystem test bed |
| ISU | international system of units |
| ISWG | Integrated Support Working Group |
| IT | identification transponder |
| IT | integrated technology |
| IT&V | integrated test and verification |
| ITA | integrated test area |
| ITA | integrated test article |
| ITA | integrated truss assembly |
| ITB | invitation to bid |
| ITC | igloo thermal control |
| ITC | integrated test configuration |
| ITD | informal test description |
| ITD | integrated technology demonstration |
| ITD | integrated test documentation |
| ITDR | integrated technology and design review |
| ITE | instrumentation test equipment |
| ITE | integration test equipment |
| ITE | intersite transportation equipment |
| ITI | inspection and test instruction |
| ITIS | ITI sheet |
| ITL | integrate, transfer, and launch |
| ITL | integrated transport launcher |
| ITMG | integrated thermal/micrometeoroid garment |
| ITO | initial time-out |
| ITO | integration and test order |
| ITP | informal test plan |
| ITP | informal test procedure |
| ITP | integral tile part |
| ITP | integrated test plan |
| ITP | integrated training plan |
| ITR | informal test result |
| ITR | integrated technology review |
| ITR | interim technical report |
| ITRB | Integrated Technical Review Board |
| ITRD | integrated test requirements document |
| ITRR | integrated technology requirements review |
| ITS | Institute for Telecommunications Sciences |
| ITS | integrated transfer subsystem |
| ITS | intercept trajectory simulation |
| ITSS | integrated tactical surveillance system |
| ITU | International Telecommunication Union |
| ITU | infrared telescope unit |
| ITV | instrumented test vehicle |
| ITV | integrated technology validation |
| ITVE | integrated technology validation experiment |
| IU | instrument unit |
| IU | interface unit |
| IUA | inertial unit assembly |
| IUA | interface unit adapter |
| IUCS | instrumentation update command system |
| IUDS | integrated utilities distribution system |
| IUE | interface unit error |
| IUE | international ultraviolet explorer |
| IUI | integrated user interface |
| IUO | interunit order |
| IURAP | International User Resource Allocation Panel |
| IUS | inertial upper stage |
| IUS | interim use sheet |
| IV | initial velocity |
| IV | integrated vehicle |
| IV | interface volume |
| IV&V | independent validation and verification |
| IVA | intravehicular activity |
| IVAR | internal variable |
| IVBC | integrated vehicle baseline characteristic |
| IVBC | integrated vehicle baseline configuration |
| IVC | intervehicular communication |
| IVE | interface verification equipment |
| IVLN | integrated vehicle logic network |
| IVP | interface verification plan |
| IVS | interface verification summary |
| IVSI | instantaneous vertical speed indicator |
| IVT | integrated verification test |
| IVT | integration, verification, and training |
| IVT | interface verification test |
| IVT | intervehicular transfer |
| IW | in work |
| IW | intrawing |
| IWBS | indirect work breakdown structure |
| IWDS | inter-work-package distributed system |
| IWFS | integrated waste fluid system |
| IWG | Interface Working Group |
| IWP | indirect work package |
| IWS | integrated water system |
| InAsSb | indium-arsenide-antimonide |
| InSb | indium antimonide |
| Isp | specific impulse |
| ips | inches per second |