| RA | Right Ascension | - | Atmospheric Research Center |
| RAE | Royal Aerospace Establishment | - | Atmospheric Research Center |
| RAL | Rutherford-Appleton Laboratory | - | Atmospheric Research Center |
| RAS | Royal Astronomical Society | - | Atmospheric Research Center |
| RASC | Royal Astronomical Society Of Canada | - | Atmospheric Research Center |
| RCC | Reinforced Carbon-Carbon | - | Atmospheric Research Center |
| RCI | Rodent Cage Interface | - | Atmospheric Research Center |
| RCS | Reaction Control System / Revision Control System | - | Atmospheric Research Center |
| RCT | Radiometric Calibration Target | - | Atmospheric Research Center |
| REM | Rat Enclosure Module | - | Atmospheric Research Center |
| RESTEC | Remote Sensing Technology Center | - | Atmospheric Research Center |
| RF | Radio Frequency | - | Atmospheric Research Center |
| RFI | Radio Frequency Interference | - | Atmospheric Research Center |
| RFM | Reconfigurable Furnace Module | - | Atmospheric Research Center |
| RFNA | Red Fuming Nitric Acid | - | Atmospheric Research Center |
| RG | Red Giant | - | Atmospheric Research Center |
| RGB | Red Giant Branch | - | Atmospheric Research Center |
| RHC | Rotational Hand Controller | - | Atmospheric Research Center |
| RIACS | Research Institute For Advanced Computer Science | - | Atmospheric Research Center |
| RKA | Rossiskoye Kosmicheskoye Agentsvo | - | Atmospheric Research Center |
| RMCD | Radaiation Monitoring Container Device | - | Atmospheric Research Center |
| RME | Radiation Monitoring Experiment | - | Atmospheric Research Center |
| RMS | Remote Manipulator System | - | Atmospheric Research Center |
| RNGC | Revised New General Catalog | - | Atmospheric Research Center |
| ROSAT | ROentgen Satellite | - | Atmospheric Research Center |
| ROUS | Rodents Of Unusual Size | - | Atmospheric Research Center |
| RPM | Retro Propulsion Module | - | Atmospheric Research Center |
| RSN | Radio SuperNova | - | Atmospheric Research Center |
| RTG | Radioisotope Thermoelectric Generator | - | Atmospheric Research Center |
| RTLS | Return To Launch Site | - | Atmospheric Research Center |
| RVSN | Raketniye Voiska Stratigcheskovo Naznacheniya | - | Atmospheric Research Center |
