PFRX means Preflight Relmat
X-1,2,3...9 or A,B,C...Z in
NASA
Similar to PFRX
A/C - Aircraft
A/C - Associate Contractor
A/C - Air Conditioning
A/D - Analog-to-Digital
A/E - Architectural and Engineering
A/E - Activity Elements
A/F - Air-to-Fuel Ratio
View all in NASA