RSYS means Responsible System in
NASA
Similar to RSYS
AA - Antenna Assembly
AAA - Avionics Air Assembly
AAC - Aft Access Closure
AACB - Aeronautics and Astronautics Coordinating Board
AAD - Attitude Anomaly Detector
AAFE - AeroAssist Flight Experiment
AAFM - Acoustic Atomic Force Microscopy
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