Hypergolic ignition

Hypergolic ignition occurs when two substances, typically rocket propellants, ignite spontaneously upon contact without needing an external spark or flame. This happens because one substance is a fuel and the other an oxidizer, and their chemical reaction immediately releases energy. This property simplifies rocket engine design, allowing for reliable and instant ignition, which is crucial for precise space maneuvers. Hypergolics are commonly used in spacecraft thrusters, satellite station-keeping, and rocket stages because their quick ignition and storability make them dependable, though they are often toxic and require careful handling.