Neutral Buoyancy Laboratory Fast Facts

The Neutral Buoyancy Laboratory, or NBL, pool is 62 meters (202 feet) in length, 31 meters (102 feet) in width and 12 meters (40 feet) in depth -- 6 meters (20 feet) above ground level and an equal distance below ground.

The pool holds 22.7 million liters (6.2 million gallons) of water.

Water in the pool is recycled every 19.5 hours.

The NBL is 12 times larger than the Weightless Environment Training Facility it replaced.

The 500 truckloads of cement required to pour the foundation stopped traffic for several miles.

It took more than a month to fill the pool with water.

Astronauts spend seven hours training in the water for every hour they will spend spacewalking during a mission.

Astronaut Jerry Ross was the first suited astronaut in the pool.

A medical team is present during all training exercises to monitor the condition of all dive personnel.

Astronauts in the pool have two-way communication capability with flight controllers in the Mission Control Center, which is several miles away.

Extravehicular Mobility Unit, or EMU, suits worn by astronauts in the pool weigh about 127 kilograms (280 pounds).

Shuttle crewmembers train for emergency water bailout and rescue in the NBL pool.