| Abbreviation | Definition |
|---|---|
| ALSE | Astronaut Life Support Equipment |
| ALSJ | Apollo Lunar Surface Journal (NASA) |
| ALSS | Air Lock Support System |
| ALSS | Apollo Logistics Support System |
| ALT | ALTimeter |
| ALT | Approach and Landing Test |
| ALTM | Altimeter |
| ALTR | Approach and Landing Test Requirement |
| ALU | A Linked Unit |
| ALU | Arithmetic Unit |
| AM | Actuator Mechanism |
| AM | Administration and Management Operations Directorate |
| AM | Aerospace Medicine |
| AM | Alpha Meter |
| AM | Ammeter |
| AM | Antenna Management |
| AMA | Air Material Area (now Air Logistics Centers) |
| AMB | AMBient |
| AMC | Active Mission Control |
| AMC | Advanced Mission Computer |