The Neutral Buoyancy Space Simulator (NBSS) is a large indoor pool located at NASA’s Marshall Space Flight Center in Huntsville, Alabama. The facility is used to train astronauts for spacewalks and other extravehicular activities (EVAs) that take place outside the International Space Station (ISS). The pool is 40 feet deep and holds 6.2 million gallons of water, making it one of the largest indoor pools in the world. The water is kept at a temperature of 86 degrees Fahrenheit to provide a comfortable environment for the astronauts.

The pool is used to simulate the weightlessness of space by creating neutral buoyancy, which means that the astronauts are neither sinking nor floating in the water. This allows them to practice their spacewalking techniques and work with equipment in a realistic environment. The pool also includes a full-scale replica of the ISS, complete with modules and robotic arms, to give astronauts a realistic experience of working in space.

The NBSS has been used to train astronauts for numerous missions, including those to repair and upgrade the Hubble Space Telescope and to build and maintain the ISS. The facility is also used to test new equipment and procedures for future missions, such as the Artemis program which aims to return humans to the Moon by 2024. The pool is a critical component of astronaut training and has helped to ensure the success of numerous space missions.

The NBSS is not open to the public, but visitors can view the pool from a gallery located above the facility. The gallery features interactive displays and exhibits that explain the science and technology behind the pool and the training that takes place there. The NBSS is a unique and important facility that plays a vital role in the training of astronauts and the success of space missions.