AK20F means 80% nitric acid + 20% N2O4 + fluorine passivant
AK = Azotna Kislota = Nitric Acid in
NASA
Similar to AK20F
A/G - Air to Ground
A/L - AutoLand
A/L - AirLock
A/L - Approach and Landing
AA - Astronomical Applications
AA - Adverse Action
AA - Antenna Assembly
View all in NASA