Astronauts in space or on the Moon face a microgravity environment. NASA feels that training astronauts underwater will give them the closest simulation to that environment.
Artemis program, the Houston, Texas-based National Aeronautics and Space Administration's next manned moon mission is slated for the year 2024. The spacesuits that the astronauts will don during the mission has already been designed, and now NASA is conducting several tests for the Extravehicular activity (EVA) apparels to perfect its wearability and functionality, underwater.
Why Underwater?
Astronauts have to be very comfortable while wearing these specially designed suits because they have to walk in them in an environment unlike that of the Earth and perform complex tasks, like handling tools and checking equipment. Wearing them underwater apparently gears them more closely to the microgravity, rather than zero-gravity, of the Moon. While on the Moon, Astronauts feel this sense - which is extremely close to weightlessness, but not exactly zero-gravity, from being in a constant free-fall as a result of the space-station which is perpetually falling in a circular motion around the Earth. Though synonymous with weightlessness or Zero-Gravity, the g-forces in a microgravity ecosystem are very, very close to but never exactly zero.
Space Pool
The aquatic facility at the Neutral Buoyancy Lab, where these tests are being carried out, is more than the size of nine Olympic-sized pool. 102 feet wide, and almost double in length at 202 feet, the 40.5 feet deep reservoir can hold 6.2 million gallons of water. Practising under such a huge mass of water, the astronauts get to experience the metrics of microgravity, the closest.
In order to completely mimic the actual work-environment, the pool contains a full-scale mockup of space-station components and cargo-carrying spacecraft for resupply missions, like SpaceX's Dragon capsule and the Japan Aerospace Exploration Agency's H-II Transfer Vehicle, as well.
The Training
During the spacewalk training sessions, the astronauts typically float around the pool engaging in drills with the space station mockup model in the Artemis-mission space-suits which are weighted to be neutrally buoyant so that they neither sink nor float.
Additional Preparation
To supplement the learning adduced from the Neutral Buoyancy Lab, NASA is also developing Moonwalk training modules at the large outdoor training area in Johnson Space Centre's Rockyard, which can stimulate the sloping, rocky terrain of the Earth's only natural satellite.
Underwater Training Testimonials
In general, all the astronauts who are undergoing this training have unequivocally maintained that training for space-station underwater is surprisingly doing them a world of good. Specifically, experienced astronaut Nick Hague, narrated in NASA's 'Curious Universe' podcast that during his first-ever spacewalk he felt the Moon's environment to be exactly like he did when in the pool.
