The federal government announced the launching of a sophisticated undersea research station that allows scientists to work for "virtually unlimited time" to examine the ocean depths. The National Oceanic and Atmospheric Administration said the 81-ton station, called Aquarius, has been placed on the floor of the Salt Water Canyon off the island of St. Croix in the U.S. Virgin Islands. The $5.5-million station, which is 43 feet long, 12 feet wide and 16 1/2 feet high, has three compartments and can house up to six people. It replaces the undersea station, Hydrolab, which completed nearly 200 missions between 1966 and 1985 for NOAA. The new station "makes it possible for scientists to live and work on the ocean floor for virtually unlimited time, allowing a nine-hour day of research before returning to the habitat," NOAA said.