In September 2002, Kelly served as the commander of the mission aboard the "Aquarius" underwater laboratory, 4 mi offshore from Key Largo. The NEEMO 4 crew spent five days saturation diving from "Aquarius" as a space analogue for working and training under extreme environmental conditions. The mission was delayed due to Hurricane Isidore, reducing the underwater duration to five days. In April 2005, Kelly was a crew member on the three-day mission. During the NEEMO 8 mission, the crew practiced construction while conducting an extravehicular activity (EVA) using a remotely operated underwater vehicle, and training with the Exploration Planning Operations Center at the Johnson Space Center.