Underwater spacewalks recreate the 'moon' in a giant NASA pool (photos)
NASA's Neutral Buoyancy Laboratory has trained spacewalking astronauts in a pool for 30 years. Now a part of the facility is changing to address a forecast demand for moon missions.

Before walking on the moon, future astronauts may go for a swim.
The famed Neutral Buoyancy Laboratory (NBL) near NASA's Johnson Space Center in Houston has trained hundreds of spacewalkers since 1992. All International Space Station crews spend many hours by simulated space modules in the large, indoor pool of water. There, they gradually get used to floating, turning screws, mounting hardware and other activities — all within reach of trained safety divers.
But with NASA now aiming to put astronauts on the moon, a part of the underwater facility is rapidly changing.
Nearby the ISS training area is a growing lunar-like world. Simulated sand and boulders (both natural and artificial) ornament the pool floor. Prototype spacesuits and lunar vehicles take dives.
Even the strange sun conditions on the moon are coming into focus, as company V2X experiments with the lighting that NASA astronauts will face at the moon's south pole in 2025 or so, when Artemis 3 goes on the surface.
As NASA expands its Artemis program at the moon, the agency expects that commercial companies will quickly follow it there. Already an agency-supported program called Commercial Lunar Payload Services (CLPS) has a set of payloads, landers and rovers aiming to touch the surface as soon as this year.
V2X expects the demand to quickly grow, and they want to be ready with their underwater moon world for whoever needs to train for spacewalks in a strictly monitored environment.