| Abbreviation | Definition |
|---|---|
| OAFD | Orbiter Air Flight Deck |
| OAFTO | Orbiter Atmospheric Flight Test Office |
| OAL | OverAll Level |
| OALC | Ogden Air Logistics Center |
| OAMS | Orbital Attitude and Maneuvering System |
| OANS | Orbiter Ancillary |
| OANS | Orbiter ANcillary System |
| OAO | Orbiting Astronomical Observatory |
| OAO-3 | Orbiting Astronomical Observatory 3 |
| OART | Office of Advanced Research and Technology |
| OAS | Office Automation System |
| OAS | Orbiter Aeroflight Simulator |
| OAS | Orbiter Atmospheric Simulator |
| OAS | Orbiter Avionics System |
| OASCB | Orbiter Avionics Software Control Board |
| OASIS | Oceanic and Atmospheric Scientific Information System |
| OASIS | Operational Analysis and Simulation of Integrated Systems |
| OASPL | Overall Sound Pressure Level |
| OAST | Office of Aeronautics and Space Technology (now OAET) |
| OAT | Operational Acceptance Test |