A hypergolic propellant combination used in a rocket engine is one whose components spontaneously ignite when they come into contact with each other. The two propellant components usually consist of a fuel and an oxidizer.

What is a hypergolic reaction?

Definition. A hypergolic mixture ignites upon contact of the components without any external source of ignition (heat or flame). There are relatively few instances where this is a desirable event... unless you're a rocket scientist or weapons designer.

Is RP-1 and lox hypergolic?

RP-1 is a special type of kerosene covered by Military Specification MIL-R-25576. In Russia, similar specifications were developed under specifications T-1 and RG-1. Nitrogen tetroxide and nitric acid are hypergolic with hydrazine, MMH and UDMH. Oxygen is not hypergolic with any commonly used fuel.