Four astronauts recently completed training to help prepare for a planned visit to an asteroid, or space rock. The four trained in a special laboratory five kilometers from Key Largo in southern Florida. They worked and lived 19 meters below the sea surface in the world's only underwater research laboratory.
The astronauts spent nine days in the "Aquarius" laboratory. Florida International University operates the 37-square meter lab.
The training came as part of a project of NASA -- the National Aeronautics and Space Administration. The project is called NEEMO, for NASA's Extreme Environment Mission Operations.
The name may lead some people to think of Captain Nemo, the star of Jules Verne's book, "Twenty Thousand Leagues under the Sea." And a little fish called Nemo was the hero of the 2003 family film "Finding Nemo."
The four NEEMO astronauts lived in conditions like those that they would face on a visit to a near-Earth asteroid. The astronauts tested the ability of human beings to exist and work in difficult conditions. And they left their underwater home only to go into surrounding ocean waters.
American astronaut Jeanette Epps said she and another astronaut did a kind of spacewalk under the water.
"That took a little bit of time to get up and running because we had a few issues with the communication in our helmets so that we can be able to talk to the crew inside the habitat and the topside."
Their temporary underwater home was not deep enough to require them to decompress each time they left Aquarius. That meant their dives could last longer. Decompression involves reducing air pressure on a person who has been under high pressure while diving deep underwater. Decompression sickness can be deadly.
Steve Bowen is lowered into the Neutral Buoyancy Laboratory at Johnson Space Center to test spacewalk suits and tools for a mission to an asteroid.
European Space Agency astronaut Thomas Pesquet of France said the crew tested human health and behavior inside the lab. They wore badges, devices that recorded their positions or social interaction. The French astronaut described the goal as gaining better understanding of reactions among people in such close surroundings, like those in space.
The four astronauts received help from people who have worked in the undersea lab before. Japanese astronaut Akihiko Hoshide said these technical experts care for all operating systems on the lab, including the space suits that the astronauts wore. He said the technicians know everything about the laboratory.
"They are the people behind the scenes. We just do the mission but without their help we can't do anything."
I'm Jeri Watson.