NASA's Undersea 'Asteroid' Mission NEEMO 16 in Photos

NEEMO 16 Mock Asteroid Spacewalk

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.

NEEMO Aquanauts Testing Surface Operations

NASA’s Extreme Environment Mission Operations (NEEMO) aquanauts test and develop surface operations. Photo released June 13, 2012.

NEEMO 16 Aquanauts on Deck

The aquanauts of NEEMO 16 mission pose for a group picture on the first day of the mission, June 11, 2012.

NEEMO 16 Participants Entering the Water

NEEMO 16 participants enter the water on Day 1 of the mission, June 11, 2012.

NEEMO 16 Light Test Day 1

NEEMO 16 participants seen outside and inside Aquarius on Day 1 of the mission, June 11, 2012.

NEEMO 16 Light Test Day 1 #2

NEEMO 16 participants seen outside and inside Aquarius on Day 1 of the mission, June 11, 2012.

Dottie Suiting as EV1 MD2

NASA posted this photo of NEEMO 16 activities taken on June 12, 2012. They wrote: "Dottie suiting as EV1 MD2."

NEEMO 16 Underwater Camera

An underwater camera floats on June 13, 2012, as part of the NEEMO 16 mission.

NEEMO 16 Divers and Sub

NEEMO 16 divers pose with mini-sub on June 13, 2012, the third day of the mission.

Miniature Submarine

A miniature submarine operates during the NEEMO 16 mission. Photo taken June 13, 2012.

NEEMO 16 Diver with Sub in Background

A NEEMO 16 diver is seen with the sub in the background. Photo taken on June 14, 2012, day four of the mission.