Space transport engineering, spaceflight engineering, astronautics, astronautical engineering, cosmonautics, rocketry, spacecraft, rockets and missiles.
| Acronym | Sense | Language | Topics | 
|---|---|---|---|
| OFP | Orbiter Flight Program | In English | |
| OFS | Orbital/Orbital Flight System | In English | |
| OFS | Orbiter Flight Simulator | In English | |
| OFS | Orbiter Functional Simulator | In English | |
| OFT | Operational Flight Test | In English | → Aeronautics, aircraft | 
| OFT | Orbital Flight Test | In English | → Quality management | 
| OFT | Orbital Flight Training | In English | → Education | 
| OFTDS | Orbital Flight Test Data System | In English | → Data | 
| OGA | Outer Gimbal Angle | In English | |
| OGA | Outer Gimbal Axis | In English | |
| OGMT | Orbiter Greenwich Mean Time | In English | → Standardization | 
| OHA | Orbital Height Adjustment Maneuver | In English | |
| OHGVT | Orbital Horizontal Ground Vibration Test | In English | |
| OI | Orbiter Insertion | In English | |
| OI | Orbiter Instrumentation | In English | |
| OIA | Orbiter Interface Adapter | In English | → Human-computer interaction | 
| OIC | Orbital Integrated Checkout | In English | |
| OIE | Orbiter Integration Engineering | In English | |
| OIS | Orbit Injection Subsystem | In English | |
| OIS | Orbit Inserting System | In English | |
| OIS | Orbit Insertion Subsystem | In English | |
| OIS | Orbiter Instrumentation Systems | In English | |
| OIT | Orbiter Integrated Test | In English | |
| OIT | Orbiter Integration Test | In English | |
| OIT | Orbiter Interface Test | In English | → Human-computer interaction | 
| OIVS | Orbiter Interface Verification Set | In English | → Human-computer interaction | 
| OLERD | Orbiter Landing Emergency Rescue Data | In English | → Data | 
| OLF | Orbiter Lifting Frame | In English | |
| OLIF | Orbiter Landing Instrumentation Facility | In English | |
| OLOW | Orbiter Lift-Off Weight | In English | |
| OLSP | Orbiter Logistics Support Plan | In English | |
| OMA | Orbiter Maintenance Area | In English | → Maintenance and logistics | 
| OMBUU | Orbiter Midbody Umbilical Unit | In English | |
| OMCF | Orbiter Maintenance and Checkout Facility | In English | → Maintenance and logistics | 
| OMDP | Orbiter Maintenance Down Period | In English | → Maintenance and logistics | 
| OME | Orbital Maneuvering Engine | In English | |
| OME | Orbiter Main Engine | In English | |
| OMET | Orbiter Mission Elapsed Time | In English | |
| OMEWG | Orbiter Maintenance Engineering Working Group | In English | → Maintenance and logistics | 
| OMK | Orbiter Mission Kit | In English | |
| OML | Orbiter Mold Line | In English | |
| OMMH | Orbiter Maintenance Man-Hour | In English | → Maintenance and logistics | 
| OMR | Orbiter Management Review | In English | → Management | 
| OMRF | Orbiter Maintenance and Refurbishment Facility | In English | → Maintenance and logistics | 
| OMRF | Orbiter Modification and Refurbishment Facility | In English | → Maintenance and logistics | 
| OMS | Orbital Maneuvering System | In English | |
| OMV | Orbital Maneuvering Vehicle | In English | |
| ONBT | Orbiter Neutral Buoyancy Trainer | In English | |
| ONERA | Office National d'Études et de Recherches Aérospatiales (www.onera.fr) | In French | → Research institutes → Aeronautics, aircraft → France  | 
| OOD | Orbiter On Dock | In English | |
| OOH | Orbital Operations Handbook | In English | |
| OOR | On-Orbit Review | In English | |
| OOS | On-Orbit Station | In English | |
| OOS | Orbit-to-Orbit Shuttle | In English | |
| OOS | Orbit-to-Orbit Stage | In English | |
| OOSD | On-Orbit Support Document | In English | |
| OOSD | Orbital Operations Support Document | In English | |
| OOSDP | On-Orbit Station Distribution Panel | In English | |
| OOSS | On-Orbit Support System | In English | |
| OPBS | Orbiter Payload Bay Simulator | In English | |
| OPF | Orbiter Processing Facility | In English | |
| OPI | Orbiter Payload Interrogator | In English | |
| OPIS | Orbiter Prime Item Specification | In English | |
| OPL | Orbiter Project Parts List | In English | |
| OPLF | Orbiter Processing and Landing Facility | In English | |
| OPM | Outer Planet Mission | In English | → Astronomy | 
| OPO | Orbiter Project Office | In English | |
| OPPAR | Orbiter Project Parts Authorization Request | In English | |
| OPR | Orbiter Payload Recorder | In English | |
| OPS | Orbiter Project Schedule | In English | |
| OPSS | Orbital Propellant Storage Subsystem | In English | |
| OPWS | Orbital Payload Work Station | In English | |
| ORCUS | Orbital Recording Capability and Update System | In English | |
| ORD | Orbital Requirements Document | In English | |
| ORS | Orbital Refueling System | In English | |
| ORS | Orbital Reservicing System | In English | |
| ORS | Orbital Resupply System | In English | |
| ORT | Orbit Readiness Test | In English | |
| ORU | Orbital Replaceable Unit | In English | |
| ORU | Orbital Replacement Unit | In English | |
| ORV | Orbital Research Vehicle | In English | |
| OS | On-orbit Station | In English | |
| OS | Orbiter CEI Specification | In English | |
| OSC | Orbital Sciences Corporation | In English | |
| OSCAR | Orbiting Satellite Carrying Amateur Radio | In English | → Telecommunications | 
| OSCN | Orbiter Specification Change Notice | In English | |
| OSCR | Orbiter Software Change Request | In English | → Software | 
| OSCRS | Orbital Spacecraft Consumables Resupply System | In English | → Maintenance and logistics | 
| OSDH | Orbiter System Definition Handbook | In English | |
| OSE | Orbital Support Equipment | In English | |
| OSF | Orbiter Simulation Facility | In English | |
| OSM | On-Orbit Spares Model | In English | |
| OSM | Orbiter Service Module | In English | |
| OSO | Orbiting Solar Observatory | In English | → Observatories → Solar system  | 
| OSOP | Orbiter Systems Operating Procedure | In English | |
| OSS | Office of Space Sciences | In English | → Astronomy | 
| OSS | Orbiting Space Station | In English | |
| OSSA | Office of Space Science and Applications | In English | → Astronomy | 
| OSSA | Office of Space Sciences and Applications | In English | → Astronomy | 
| OSSIU | Orbiter-Space Station Interface Unit | In English | → Human-computer interaction | 
| OSSRH | Orbiter Subsystem Requirements Handbook | In English | |
| OST | Orbiter Support Trolley | In English | |
| OSTA | Office of Space and Terrestrial Applications | In English | → Astronomy | 
| OSTDS | Office of Space Tracking and Data Systems | In English | → Data | 
| OSTO | Office of Space Transportation Operations | In English | |
| OSTP | Orbiting System Test Plan | In English | |
| OSTS | Office of Space Transportation Systems | In English | |
| OTA | Operational Trajectory Analysis | In English | → Aeronautics, aircraft | 
| OTB | Orbiting Tanker Base | In English | |
| OTC | Orbiter Test Conductor | In English | |
| OTD | Orbiter Test Director | In English | |
| OTE | Orbital Transfer Equipment | In English | |
| OTLC | Orbiter Time Line Constraint | In English | |
| OTOS | Orbit-To-Orbit Stage | In English | |
| OTS | Orbital Test System | In English | |
| OTS | Orbital/Orbital Transfer System | In English | |
| OTV | Orbit Test Vehicle | In English | |
| OTV | Orbital Transfer Vehicle | In English | |
| OUT | Orbiter Utility Tray | In English | |
| OV | Orbital Vehicle | In English | |
| OV | Orbiter Vehicle | In English | |
| OVEI | Orbiter Vehicle End Item | In English | |
| OVNI | Objet Volant Non Identifié = OVNI | Objecte Volador No Identificat | In Catalan = НЛО | Неидентифициран летящ обект | In Bulgarian = OVNI | Objeto Volador No Identificado | In Spanish = UFO | Unidentifiziertes Flugobjekt | In German = UFO | Unidentified Flying Object | In English = UFO | Unknown Flying Object | In English = UFO | Uidentificeret flyvende objekt | In Danish = NIFO | Neidentigita Fluganta Objekto | In Esperanto = UFO | Unbekend fleanend objekt | In Frisian = עב"מ | עצם בלתי מזוהה | In Hebrew = OVNI | Oggetto Volante Non Identificato | In Italian = NLO | Neidentificēts lidojošs objekts | In Latvian = UFO | Uidentifisert flygende objekt | In Norwegian = UFO | Uidentifisert flygande objekt | In Nynorsk = NOL | Niezidentyfikowany Obiekt Latający | In Polish = OVNI | Objeto Voador Não Identificado | In Portuguese = OZN | Obiect Zburător Neidentificat | In Romanian = НЛО | Неопознанный летающий объект | In Russian = NLO | Neidentifikovani leteći objekat | In Serbo-Croatian  | 
In French | |
| OVNI | Objecte Volador No Identificat = НЛО, UFO, NIFO, עב"מ, NLO, NOL, OZN (look above)  | 
In Catalan | |
| OVNI | Objeto Volador No Identificado = НЛО, UFO, NIFO, עב"מ, NLO, NOL, OZN (look above)  | 
In Spanish | |
| OVNI | Oggetto Volante Non Identificato = НЛО, UFO, NIFO, עב"מ, NLO, NOL, OZN (look above)  | 
In Italian | |
| OVNI | Objeto Voador Não Identificado = НЛО, UFO, NIFO, עב"מ, NLO, NOL, OZN (look above)  | 
In Portuguese | |
| OZN | Obiect Zburător Neidentificat = OVNI, НЛО, UFO, NIFO, עב"מ, NLO, NOL (look above)  | 
In Romanian | |
| P&E | Propellant and Explosive | In English | → Chemical technology | 
| P&SS | Planetary and Space Science | In English | → Serial publications, periodicals → Astronomy  | 
| PACA | Payload Accommodation Configuration Assessment | In English | |
| PACK | Payload Active Cooling Kit | In English | |
| PACRUSS | Passive and Active Control of Space Structures | In English | |
| PACS | Pointing and Attitude Control System | In English | |
| PAD | Propellant Acquisition Device | In English | |
| PADSIM | Precision Attitude Determination Simulation | In English | |
| PAF | Payload Attach Fitting | In English | → Mechanical engineering | 
| PAH | Payload Accommodations Handbook | In English | |
| PALS | Precision Approach and Landing System | In English | → Aeronautics, aircraft | 
| PAM | Payload Assist Module | In English | |
| PAMELA | Payload for Antimatter Matter Exploration and Light-nuclei Astrophysics | In English | → Astronomy | 
| PAP | Payload Accommodation Plan | In English | |
| PAP | Payload Adapter Plate | In English | |
| PAPG | Programm zur Auswertung von Pappgassenversuchen | In German | → Aeronautics, aircraft | 
| PAS | Payload Accommodation Study | In English | |
| PATH | Postflight Attitude and Trajectory History | In English | → Aeronautics, aircraft | 
| PATS | Payload Avionics Test Station | In English | → Aeronautics, aircraft | 
| PBD | Payload Bay Door | In English | → Mechanical engineering | 
| PBDM | Payload Bay Door Mechanism | In English | → Mechanical engineering | 
| PBK | Payload Bay Kit | In English | |
| PBL | Payload Bay Liner | In English | |
| PBS | Payload Berthing System | In English | |
| PBTS | Payload Bay Transfer System | In English | |
| PBV | Post Boost Vehicle | In English | → Military engineering | 
| PCC | Payload Control and Checkout | In English | |
| PCCE | Payload Common Communication Equipment | In English | |
| PCDU | Payload Command Decoder Unit | In English | |
| PCF | Payload Control Facility | In English | |
| PCIL | Pilot-Controlled Instrument Landing | In English | → Aeronautics, aircraft | 
| PCK | Payload Command Kit | In English | |
| PCOT | Payload Center Operations Team | In English | |
| PCR | Payload Changeout Room | In English | |
| PCR | Payload Checkout Room | In English | |
| PCR | Payload Clean Room | In English | |
| PCRS | Payload Cover Removal System | In English | |
| PCS | Probability of Crew Safety | In English | → Accidents, risks, safety → Aeronautics, aircraft  | 
| PCS | Payload Checkout System | In English | |
| PCS | Payload Control Subsystem | In English | |
| PCS | Payload Control Supervisor | In English | |
| PCTC | Payload Crew Training Complex | In English | → Education | 
| PCTO | Payload Cost Tradeoff Optimization | In English | → Prices | 
| PCU | Payload Checkout Unit | In English | |
| PCVL | Pilot-Controlled Visual Landing | In English | → Aeronautics, aircraft | 
| PD&RS | Payload Deployment and Retrieval Subsystem | In English | |
| PDA | Payload Disconnect Assembly | In English | |
| PDA | Propellant Drain Area | In English | |
| PDD | Payload Description Document | In English | |
| PDI | Payload Data Interleaver | In English | |
| PDM | Payload Deployment Module | In English | |
| PDP | Payload Data Pack | In English | |
| PDP | Postinsertion Deorbit Preparation | In English | → Astronomy | 
| PDRM | Payload Deployment and Retrieval Mechanism | In English | |
| PDRR | Payload Design Requirements Review | In English | |
| PDRS | Payload Deployment and Retrieval System | In English | |
| PDRS | Payload Data and Retrieval System | In English | |
| PDRSS | Payload Deployment and Retrieval System Simulation/Simulator | In English | |
| PDS | Pathfinder Demonstration Satellite | In English | |
| PDT | Payload Data Tape | In English | |
| PDU | Pilot Display Unit | In English | → Human-computer interaction → Aeronautics, aircraft  | 
| PE | Payload Element | In English | |
| PEA | Payload Electronics Assembly | In English | → Electronics | 
| PEDB | Payload Engineering Database | In English | |
| PEFU | Payload Effects Follow-Up Study | In English | |
| PEM | Payload Electronics Module | In English | → Electronics | 
| PF | Payload Function | In English | |
| PF | Powered Flight | In English | → Aeronautics, aircraft | 
| PFB | Payload Feedback | In English | |
| PFB | Payload Forward Bus | In English | → Computer architecture | 
| PFC | Performance Flight Certification | In English | → Aeronautics, aircraft | 
| PFC | Postflight Checklist | In English | → Aeronautics, aircraft |