A moon pool is an opening in the bottom of a marine vessel, such as a research ship or oil rig, that allows access to the water below. This design enables equipment and personnel to enter and exit the water while minimizing the impact of waves and currents. Moon pools are often used for underwater operations, including submarine launches, diving, and scientific research. The structure of a moon pool typically includes a vertical shaft that extends down into the water, providing a safe and controlled environment for various activities. By reducing the effects of surface conditions, moon pools enhance the safety and efficiency of underwater missions, making them valuable in both commercial and scientific applications.