| Abbreviation | Definition |
|---|---|
| P/PL | Primary Payload |
| P/S | Parallel-to-Serial Converter |
| P/S | Payload Specialist |
| P/Y | Pitch/Yaw |
| P1 | Port 1 |
| PA | Pad Abort |
| PA | Paging and Area Warning |
| PA | Power Amplifier |
| PA | Pulse Amplifier |
| PAC | Pressure Alpha Center |
| PAC | Principal Advisory Committee |
| PAC | Probe Aerodynamic Center |
| PAC | Problem Action Center |
| PACAS | Personnel Access Control Accountability System |
| PACC | Problem Action Control Center |
| PACE | Prelaunch Automatic Checkout Equipment |
| PACI | Payload and Attitude Control Interface |
| PACOR | Packet Processor |
| PACORII | Processor Data Capture Facility II |
| PACS | Photoconductor Array Camera and Spectrometer |