| Acronym | Meaning |
 | R | Roll |
 | R | Yaw Rankine Rate |
 | R | LEO Request Liaison Engineering Order |
 | R | LSS Regenerative Life Support System |
 | R | BARRadius Vector Axis |
 | R | DOTRange Rate To Target |
 | R | ETSReconfigurable Electrical Test Stand |
 | R | ETSReconfiguration Electrical Test Stand |
 | R | IMPMinimum Range To Avoid Plum Impingement |
 | R&CC | Recorder And Communication Control |
 | R&D | Research And Development |
 | R&DO | Research And Development Operations (MSFC) |
 | R&OA | Reliability And Quality Assurance |
 | R&P | Reserve And Process |
 | R&PM | Research And Program Management |
 | R&R | Remove And Replace |
 | R&R | Rendezvous And Recovery |
 | R&Z | Range And Zero |
 | R-T | Resistance Test |
 | R/A | Radar Altimeter |
 | R/C | Radio Command |
 | R/C | Rate Of Climb |
 | R/C | Remote Control |
 | R/D | Rate Of Descent |
 | R/E | Reentry |
 | R/I | Receiving Inspection |
 | R/L | Rate/Limited |
 | R/L | Remote/Local |
 | R/O | Rollout |
 | R/S | Range Safety |
 | R/S | RedundantSet |
 | R/T | Real Time |
 | R/T | Receiver/Transmitter |
 | R/W | Read/Write |
 | R/W | Runway |
 | RA | Radar Altimeter |
 | RA | Radar Altimeter (R/A Preferred) |
 | RA | Radium |
 | RA | Range Area |
 | RA | Right Aft |
 | RA | Right Ascension |
 | RAAB | Remote Amplifier Acquisition And Advisory Box |
 | RAAB | Remote Amplifier And Adoption Box |
 | RAAB | Remote Application And Advisory Box |
 | RAC | ReliabilitY Action Center |
 | RACS | Rotation Axis Coordin |
 | RACS | Remote Automatic Calibration System |
 | RACU | Remote Acquisition And Command Unit |
 | RAD | Radar |
 | RAD | Radian |