Space exploration presents many unique challenges to humans. In order to prepare astronauts for these extreme environments in space, NASA engineers and scientists use comparable environments on Earth. One of the most extreme environments is the ocean. Not only is the ocean a harsh and unpredictable environment, but it has many parallels to the challenges of living and working in space.
The NASA Extreme Environment Mission Operations project, known as NEEMO, sends groups of astronauts, engineers, doctors and professional divers to live in an underwater habitat for up to three weeks at a time. These crew members, called aquanauts, live in Aquarius, the world's only undersea laboratory, located 3.5 miles off the coast of Key Largo, Fla.
Most underwater activities are accomplished by traditional scuba diving, but divers are limited to specific amounts of time because of the risk of decompression sickness (often called the "bends"). Based on the depth and the amount of time spent underwater, inert gases such as nitrogen will build up in the human body. If a diver ascends out of the water too quickly, the gases that were absorbed can create bubbles within the diver's body as the surrounding pressure reduces.
A technique known as saturation diving allows people to live and work underwater for days or weeks at a time. After twenty four hours at any underwater depth, the human body becomes saturated with dissolved gas. Therefore, the diver can accurately predict exactly how much time is needed to decompress before returning to the surface, which limits the risk of decompression sickness. By living in the Aquarius habitat and working at the same depth on the ocean floor, NEEMO crews are able to remain underwater for the duration of their mission.
The physical and psychological isolation of the Aquarius habitat closely mirrors the isolation that can occur during space exploration. Communication between astronauts and Mission Control is highly important, but during future long duration missions, there will be times where this communication may not be available. Therefore, crews must be able to work independently from the mission control team.
NEEMO missions offer the opportunity to test new techniques for telecommunications. Aquanauts and engineers work to develop new ways to interact with researchers from a remote laboratory location, much like they do with the space station. In addition, they have tested new communication technology for use when a space walking crew is working at a significant distance from the laboratory.
Strong emphasis is placed on exercising team building and leadership skills among the NEEMO crews, which enables them to continue working efficiently when they are unable to communicate with a mission control center. It is important to practice the plans, procedures and training that are vital to long duration exploration missions when there is the possibility of less direct communication with mission control.