The NASA Extreme Environment Mission Operations (NEEMO) 21 mission began on 21 July 2016, as an international crew of aquanauts splashed down to the undersea Aquarius Reef Base, 20 m below the surface of the Atlantic Ocean off the Florida Keys. The NEEMO 21 crew performed research inside and outside the habitat during a 16-day simulated space mission. During simulated spacewalks underwater, they evaluated tools and mission operation techniques that could be used in future space missions. Inside the habitat, the crew tested a DNA sequencer, a medical telemetry device and a head-up display.
Clockwise from top: Matthias Maurer (ESA), Marc O Griofa (Teloregen/VEGA/AirDocs), NASA astronaut Megan McArthur, NASA astronaut Reid Wiseman, Dawn Kernagis (Institute for Human & Machine Cognition), and Noel Du Toit (Naval Postgraduate School). Inside the Aquarius habitat are Florida International University Habitat Technicians Hank Stark (left) and Sean Moore (right).