The Aquarius Reef Base is an underwater habitat located 5 and a half miles off Key Largo in the Florida Keys National Marine Sanctuary. It is situated on the ocean floor 62 feet below the surface next to a deep coral reef named Conch Reef. It is used to for ocean studies, test and develop state-of-the-art undersea technology, and train specialized divers and astronauts. NASA Extreme Environment Mission Operations (NEEMO), is a NASA program that sends groups of astronauts, engineers and scientists to live in Aquarius.