| Abbreviation | Definition |
|---|---|
| MRL | Manipulator Retention Latches |
| MRL | Manipulator Retention Lock |
| MRL | Material Requirements List |
| MRM | Mission Readiness Manager |
| MRO | Mars Reconnaissance Orbiter |
| MRR | Mechanical Robotic Rover |
| MRR | Mission Readiness Request |
| MRR | Mission Reconfiguration Request |
| MRS | Management Review System |
| MRS | Mistress |
| MRSP | Mission Ready Spares Package |
| MRT | Mission Readiness Test |
| MRTC | Multiple Real-Time Commands |
| MRTT | Mission Readiness Test Team |
| MRU | Motion Reference Unit |
| MRV | Modular Re-entry Vehicle |
| MS | Machine Screw |
| MS | Machine Steel |
| MS | Man System |
| MS | Margin of Safety |