Liquid propellant rockets use a combination of liquid fuels and oxidizers to produce thrust. The fuel, such as liquid hydrogen or kerosene, is burned with an oxidizer like liquid oxygen in a combustion chamber. This reaction generates hot gases that are expelled through a nozzle, propelling the rocket forward. These rockets are known for their efficiency and controllability. Unlike solid propellant rockets, which burn their fuel all at once, liquid rockets can be throttled, shut down, or restarted during flight. This flexibility makes them suitable for various missions, including launching satellites and crewed space exploration, such as those conducted by NASA.