Hybrid rocket engines combine elements of both solid and liquid rocket propulsion systems. They typically use a solid fuel, such as rubber or plastic, and a liquid oxidizer, like liquid oxygen or nitrous oxide. This design allows for better control of thrust and improved safety compared to traditional solid rockets. These engines are often lighter and simpler to manufacture, making them attractive for various applications, including space exploration and commercial launches. Notable examples include the SpaceShipTwo developed by Virgin Galactic and the Falcon 9 rocket's first stage, which utilizes hybrid technology for specific missions.