| A/L | Air Lock | - | Organizations |
| AAFE | Aeroassist Flight Experiment | - | Organizations |
| ABCL | As Built Configuration List | - | Organizations |
| ABHRS | As Built Hardware Reporting System | - | Organizations |
| AC | Alternating Current | - | Organizations |
| AC | Comptroller Office | - | Organizations |
| ACES | Acoustic Containerless Experiment System | - | Organizations |
| ACIP | Assembly Configuration And Integration Panel | - | Organizations |
| ACR | Active Cavity Radiometer | - | Organizations |
| ACRBC | Acceptance | - | Organizations |
| ACRC | Assured Crew Return Capability - Now ACRV | - | Organizations |
| ACRIM | Active Cavity Radiometer Irradiance Monitor | - | Organizations |
| ACRV | Assured Crew Return Vehicle | - | Organizations |
| ACTS | (TOS) Advanced Communications Technology Satellite | - | Organizations |
| AD | Aperture Door | - | Organizations |
| ADC | Affiliated Data Center | - | Organizations |
| ADEOS | Advanced Earth Observing Mission | - | Organizations |
| ADP | Acceptance Data Package | - | Organizations |
| ADP | Automated Data Processing | - | Organizations |
| ADPS | Acceptance Data Package System | - | Organizations |
| ADSF | Advanced Directional Solidification Furnace | - | Organizations |
| AEG | AEG Telefunken | - | Organizations |
| AEPI | Atmospheric Emissions Photo Imaging | - | Organizations |
| AES | Atmospheric Exchange System | - | Organizations |
| AESE | Airborne Electrical Support Equipment | - | Organizations |
| AFB | Air Force Base | - | Organizations |
| AFD | Aft Flight Deck | - | Organizations |
| AFE | American Flight Echocardiograph | - | Organizations |
| AFP | Air Force Program | - | Organizations |
| AFR | Air Force Regulation | - | Organizations |
| AFSCF | Air Force Satellite Control Facility | - | Organizations |
| AFTA | Aft Frame Tilt Actuator | - | Organizations |
| AFTE | Autogenic Feedback Training Experiment | - | Organizations |
| AGOSS | Automated Ground Operations Scheduling System | - | Organizations |
| AHU | Air Handling Unit | - | Organizations |
| AI | Artificial Intelligence | - | Organizations |
| AIRS | Atmospheric Infrared Sounder | - | Organizations |
| AIT | Aeritalia | - | Organizations |
| ALAE | Atmospheric Lyman Alpha Experiment | - | Organizations |
| ALC | Augmented Landing Site | - | Organizations |
| ALERT | Acute Launch Emergency Reliability Tip | - | Organizations |
| ALRUTS | Automated Line Replaceable Unit Tracking System | - | Organizations |
| ALS | Advanced Launch System | - | Organizations |
| ALT | Altimeter | - | Organizations |
| AMF | Astronaut Memorial Foundation | - | Organizations |
| AMSU | Advanced Microwave Sounding Unit | - | Organizations |
| ANSI | American National Standard Institute | - | Organizations |
| AO | Assembly Order | - | Organizations |
| AOA | Abort Once Around | - | Organizations |
| APC | Adaptive Payload Carrier | - | Organizations |
| APCS | Automated Project Control System - ARTEMIS | - | Organizations |
| APID | Applications Process Identification | - | Organizations |
| APS | Acquisition Processor Subsystem | - | Organizations |
| ARC | Aggregation Of Red Cells | - | Organizations |
| ARC | Ames Research Center | - | Organizations |
| ARS | Archive And Retrieval Subsystem (PPCU) | - | Organizations |
| ARTEMIS | Project Management Software System - Metier Product | - | Organizations |
| ARTS | Automated Resource Tracking System - ARTEMIS | - | Organizations |
| ASCII | American Standard Code For Information Interchange | - | Organizations |
| ASE | Airborne Support Equipment | - | Organizations |
| ASP | Attitude Sensor Package | - | Organizations |
| ASRS | Automated Support Requirements System | - | Organizations |
| ASSY | Assembly | - | Organizations |
| AST | Astro Star Tracker | - | Organizations |
| ASTER | Advanced Spaceborne Thermal Emission And Reflection Radiometer | - | Organizations |
| ASTG | Aerospace Test Group | - | Organizations |
| ATC | Absolute Time Command | - | Organizations |
| ATCS | Active Thermal Control System | - | Organizations |
| ATE | Automated Test Equipment | - | Organizations |
| ATLAS | Atmospheric Laboratory For Applications And Science | - | Organizations |
| ATMOS | Atmospheric Trace Molecule Spectroscopy | - | Organizations |
| ATP | Accelerated Training Program | - | Organizations |
| ATP | Acceptace Test Procedure | - | Organizations |
| AWAD | Assembly Work Authorization Document | - | Organizations |
