Hybrid rocket: Meaning (information, definition, explanation, facts)

A hybrid propulsion system is typically composed of solid fuel and liquid or gas oxidizer. These systems are superior to solid propulsion systems in the respects of safety, throttling, restartability, stability, and environmental cleanliness. However, hybrid systems are more complex than solids, and consequently are heavier and more expensive.

Common oxidizers include gaseous or liquid oxygen and nitrous oxide.

Several universities have recently experimented with hybrid rockets. BYU, the University of Utah and Utah State University launched a student-designed rocket called Unity IV in 1995 which used the solid propellant Hydroxy-terminated polybutadiene (HTPB) with gaseous oxygen, and in 2003 launched a larger version using HTPB with nitrous oxide.

Portland State University also launched several hybrid rockets in the early 2000's.

SpaceShipOne, the first private spacecraft, is powered by a hybrid rocket burning HTPB with nitrous oxide.