Propulsion systems refer to the mechanisms and technologies used to move vehicles or objects forward. These systems are integral to a wide range of transportation vehicles, including airplanes, spacecraft, ships, and automobiles. Propulsion systems can be powered by various sources, such as fossil fuels, electricity, or alternative fuels like hydrogen or biofuels. The design and efficiency of propulsion systems greatly impact the performance, speed, and environmental impact of vehicles. Ongoing research in this field focuses on developing more efficient, sustainable, and innovative propulsion systems to meet the growing demands of modern transportation while reducing emissions and environmental impact.