| OAO | Orbiting Astronomical Observatory | - | Atmospheric Research Center |
| OARE | Orbital Acceleration Research Experiment | - | Atmospheric Research Center |
| OCGF | Organic Crystal Growth Facility | - | Atmospheric Research Center |
| OCST | Office Of Commercial Space Transportation | - | Atmospheric Research Center |
| OCTS | Ocean Color And Temperature Scanner | - | Atmospheric Research Center |
| OCTW | Optical Communications Through The Shuttle Window | - | Atmospheric Research Center |
| OGO | Orbiting Geosurvey Observatories | - | Atmospheric Research Center |
| OMB | Office Of Management And Budget | - | Atmospheric Research Center |
| OMDP | Orbiter Maintenance Down Period | - | Atmospheric Research Center |
| OMS | Orbital Maneuvering System | - | Atmospheric Research Center |
| OPF | Orbiter Processing Facility | - | Atmospheric Research Center |
| ORBI | Stock Ticker Symbol For OSC | - | Atmospheric Research Center |
| ORFEUS | Orbiting And Retrievable Far And Extreme Ultraviolet Spectrometer | - | Atmospheric Research Center |
| OSC | Orbital Sciences Corporation | - | Atmospheric Research Center |
| OSCAR | Orbiting Satellite Carrying Amateur Radio | - | Atmospheric Research Center |
| OSS | Office Of The Space Station | - | Atmospheric Research Center |
| OSSA | Office Of Space Science And Applications | - | Atmospheric Research Center |
| OSSE | Oriented Scintillation Spectrometer Experiment | - | Atmospheric Research Center |
| OSTP | Office Of Science And Technology Policy | - | Atmospheric Research Center |
| OTA | Optical Telescope Assembly | - | Atmospheric Research Center |
| OTFE | Oscillatory Thermocapillary Flow Experiment | - | Atmospheric Research Center |
| OTHB | Over The Horizon Backscatter | - | Atmospheric Research Center |
| OTV | Orbital Transfer Vehicle | - | Atmospheric Research Center |
| OV | Orbital Vehicle | - | Atmospheric Research Center |
