Let's Go Swimming at NASA

There are many different aspects to astronaut training. However, most of their training focuses on "zero-gravity" (0-g) activities that simulate the space environment onboard the Space Shuttle and International Space Station. This training is essential primarily because of the difficulties of living and working in space. For example, the astronauts can experience a number of adverse effects while in space such as dizziness and nausea from spacial disorientation (similar to sea sickness), shifting of fluids in their body, loss of bone and muscle mass, extension of the spine, headaches, insomnia, and depression just to name a few.

Unfortunately, the "1-g" force of gravity on earth makes it very difficult to emulate the "0-g" space environment, especially for long periods of time. However, NASA has three ways to overcome this obstacle and prepare the astronauts for the space environment. The first method utilizes simulators, robotics and helium-filled balloons to simulate weightless objects. The next method involves a KC-135 aircraft flying a series of "0-g" dives. This allows the astronauts to experience weightlessness for approximately 30-40 seconds, but this is considered a very short time duration. The final method utilized by NASA to simulate "0-g" is the Neutral Buoyancy Lab (NBL), which is a large 202' long by 102' wide by 40' deep water tank that holds 6.2 million gallons of water.

The NBL will accommodate more training sessions simultaneously with larger segments of the ISS than any other training facility. It allows larger segments of the ISS to be represented contiguously and in the correct spatial orientation, which yields realistic operations timelines and decreases facility reconfiguration. While in the water, astronauts use standard space suits that are adjusted for neutral buoyancy. This simulates a "0-g" environment by allowing them to remain at a constant depth without sinking or floating. In essence, they "float" in the water like they "float" in space. While in the water, astronauts accomplish a number of training tasks that include: acclimation to wearing and moving in the space suits, as well as testing of space station equipment, familiarization with the flight procedures, operations of the tools and installation of hardware.

During a typical 4 - 6 hour NBL dive, there are anywhere from 8 and 10 divers supporting a crew of two astronauts during their training sessions. This is where the swimming takes place. There are Safety Divers who are responsible for safety of the astronauts; Utility Divers who assist the astronauts with tools, equipment and hardware; Camera and Video Divers who are responsible for photographs and live video images; and Observation Divers who oversee all the tasks performed by the astronauts. In order to dive in the NBL, a person needs to be a certified diver, pass a third class medical physical (similar to the one given to pilots), as well as pass exams that cover the NBL operating procedures and dive safety.