hypergols

/ˈhaɪpərˌɡɑlz/
noun
  1. Plural of hypergol; fuels that ignite spontaneously when they come into contact with an oxidizer, used especially in rocket engines.
    • The storage and handling of hypergols require special safety precautions due to their reactivity.
    • Engineers selected hypergols for the thruster system to ensure reliable performance in orbit.
    • Many spacecraft use hypergols because they don't need an external ignition source.