NASA has transformed the 23.5 million-liter Neutral Buoyancy Laboratory (NBL) swimming pool at the Sonny Carter Training Facility in Texas into an environment that simulates the Moon’s surface to train astronauts. The astronauts dive to a depth of 12 meters under the pool to experience the lunar gravity of one-sixth that of Earth, with the help of buoyancy devices and weights. The pool measures 61.5 meters by 31 meters.

NASA is working to improve the environment under the pool to help astronauts feel like they are truly working on the Moon. Experts are using rocks, sand, and even taking into account the movement of the Sun to simulate the lunar environment.

“We’re putting sand down to simulate the top layer of the lunar surface,” said Clay Tomlinson, program manager at V2X, a company contracted to build a replica of the Moon. According to Tomlinson, astronauts can get a sense of what it’s like to walk on the Moon when they step on the simulated environment.

This effort is laying the foundation for a historic mission. In NASA’s Artemis III mission, scheduled to take place later this decade, astronauts will once again walk on the Moon over 50 years since humans last set foot there.

Previously, the NBL pool was used to train astronauts to live and work long-term on the International Space Station (ISS). The facility also helped staff train for the process of recovering the Orion spacecraft. The spacecraft successfully landed in the Pacific Ocean after completing the Artemis I mission in December 2022.

NASA also plans to use the NBL to train astronauts for the Lunar Gateway, a space station that will serve as a stepping stone for astronauts on their way to the Moon’s surface in the future. With more and more companies operating in the space industry, V2X also plans to provide underwater simulation environments to more private companies.