A chemical used as an oxidizer in rocket engines. RFNA, or Inhibited RFNA, is an oxidizer for hypergolic engines, which use propellants such as unsymmetrical dimethyl hydrazine (UDMH). When RFNA oxidizer and UDMH propellants combine, they ignite spontaneously, requiring no external energy source. RFNA is often used in remotely-controlled propulsion systems on orbiting satellites and in Titan rockets.