| Abbreviation | Definition |
|---|---|
| ARS | Attitude Reference System |
| ARS | Authentication Response |
| ART | Adjustable Ranging Telescope |
| ARTEMIS | Acceleration, Reconnection, Turbulence, and Electrodynamics of the Moon’s Interaction with the Sun |
| ARTEMIS | Acceleration, Reconnection, Turbulence, and Electrodynamics of the Moons Interaction with the Sun |
| ARTS | Automated Resource Tracking System |
| ASA | Australian Space Agency |
| ASA | Austrian Space Agency |
| ASAS | Airborne Separation Assistance System |
| ASCA | Advanced Satellite For Cosmology And Astrophysics |
| ASCII | Ancient Script Code for Intelegent Interpretors |
| ASCR | Assured Safe Crew Return |
| ASDA | Area Smoke Detector Assembly |
| ASDS | Autonomous Satellite Docking System |
| ASE | Airborne Support Equipment |
| ASE | Another Space Engine |
| ASG | All Systems Go |
| ASI | Augmented Space Igniter |
| ASIMA | Asteroid Impact Analyzer |
| ASLV | Advanced Satellite Launch Vehicle |