PFRX means Preflight Relmat
X-1,2,3...9 or A,B,C...Z in
NASA
Similar to PFRX
AAV - Air Admittance Valve
AAV - Aerospace Audio- Visual
ABA - Astronaut Boarding Aircraft
ABC - Active Body Control
ABC - Audio Bus Coupler
ABCL - As Built Configuration List
ABE - Anomalous Biological Entities
View all in NASA