Four ‘Aquanauts’ Complete Mock Asteroid Mission on Ocean Floor

NASA astronaut Dottie Metcalf-Lindenburger tests different ways to anchor to the surface of an asteroid on a simulated spacewalk on the ocean floor during the NEEMO 16 mission.

Four "aquanauts" returned to dry land today (June 22), after spending 12 days living on the ocean floor off the Florida coast as part of a NASA-led mock mission to an asteroid.

The undersea explorers wrapped up the 16th expedition of the NASA Extreme Environment Mission Operations Program, or NEEMO 16 this morning, emerging from the water at 9:11 a.m. EDT (1311 GMT), NASA officials confirmed.

"The NEEMO 16 crew is back on the surface, heading back to land! Splash up time was 9:11 am ET," mission controllers relayed via Twitter.

During the 12-day mission, the aquanauts lived at the National Oceanic and Atmospheric Administration’s Aquarius Underwater Laboratory, which lies 62 feet (19 meters) below the ocean’s surface, roughly 3.5 miles (5.6 kilometers) off the coast of Key Largo in the Florida Keys.

The NEEMO 16 expedition was designed to simulate aspects of a real mission to an asteroid, focusing in particular on the most effective ways to fasten to a space rock and how to cope with communication delays with mission control, NASA officials said.

The aquanauts also performed several mock spacewalks to test different techniques for attaching to, and navigating around, on an asteroid.