A pulse detonation engine is a rocket engine that works somewhat like an automobile engine, by injecting fuel and oxidizer into long cylinders and igniting the mixture with a spark plug. The explosive pressure of the detonation pushes the exhaust out the open end of the cylinder, providing thrust to the vehicle. Pulse detonation technology is one of the approaches to future low-cost launch vehicles being investigated at Marshall Space Flight Center which could lead to lightweight, low-cost rocket engines. The pulse-jet and the nuclear pulse rocket operate using the same principle of repeated controlled explosions.