Jeremy Hansen leads undersea spacewalks on NEEMO 19 mission

Canadian astronaut Jeremy Hansen is spending seven days living at the bottom of the Atlantic Ocean and leading a crew to explore the ocean floor, to simulate and prepare for missions in space.

"For me, mentally, I'm preparing to go on a space mission for the next seven days," Hansen told CBC before his dive Monday to the Aquarius Reef Base, about 20 metres below the surface off the ocean near Key Largo, Fla.

"We'll be going to 'spacewalks,' if you will, out of the habitat every day and exploring the ocean floor as if it were an asteroid or the surface of Mars."

Hansen, who is 38 years old and originally from London, Ont., is the exploration lead for NASA's Extreme Environment Mission Operations 19 (NEEMO 19), which means that he will guide the four-member crew in planning and executing the simulated spacewalks from the base, the Canadian Space Agency says.

The first two underwater spacewalks will take place Monday.

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Hansen's mission mates include:

• NASA astronaut Randy Bresnik, commander for the mission.
• European Space Agency astronaut Andreas Mogensen.
• Herve Stevenin, ESA's head of extravehicular activity training.

The astronauts will live at the base maintained as an undersea research habitat by Florida International University.

"There's a hole in the floor that's open to the ocean all the time, and the air pressure keeps the water out, and we just go in and out," Hansen said.

"One of unique things I'm really excited [about] is just to see the ocean life. It's kind of like a big aquarium for me."

The goals of the mission are to:

• Test tools and techniques to conduct spacewalk tasks in varying levels of "gravity."
• Test technologies to improve performance on standard space station procedures.
• Investigate the effectiveness of 'just-in-time crew' training compared to longer training times.

Hansen was selected as one of Canada's two newest astronauts in 2009, along with David St-Jacques. He has never yet been on a space mission.

Canada is not expected to have another chance to send an astronaut to the International Space Station until 2017 at the earliest.