Space propulsion refers to the methods and technologies used to move spacecraft through space. It involves generating thrust to overcome gravitational forces and navigate in the vacuum of space. Common propulsion systems include chemical rockets, which burn fuel to produce thrust, and electric propulsion systems, which use electricity to accelerate ions for movement. Different types of propulsion systems are suited for various missions. For example, chemical rockets are typically used for launching spacecraft from Earth, while ion thrusters are more efficient for long-duration space missions, such as those involving satellites or interplanetary travel. Each system has its advantages and limitations based on mission requirements.