A wise person told me once (actually just before last years mission), that I should keep a journal of this incredible adventure. I didn't, and I've regretted it ever since. So this year, when another equally wise person gave me the same advice, I listened. So in goes a Train CD, out comes my pen and on comes "Drops of Jupiter..." I sing along with a slight modification, and a voice a little higher than at the surface due to the increased pressure of our air… "now that I'M back in the atmosphere..." I must admit that between the great music and the incredible view out the window at the end of my bunk, it's not that easy to stay focused on capturing my thoughts. However, right after this huge coral crab climbs off the window, I'll give it a shot.

Several things crossed my mind as I descended the 50 feet from the surface to the habitat to start this mission, our first all NASA mission to the Aquarius Undersea Research Laboratory. My mind raced. What would our adventure be like? Would we achieve all we set out to do? Was I really going to have space food for lunch…..undersea?

Growing up in the oceanfront community of Cocoa Beach, Florida, during the 1960s, I was exposed to the unique environment of the space program on a daily basis. As a kid, I often thought of what it would like to fly in space. I dreamed about what it would be like to live under the ocean. Like millions, and most members of my current crew, Jacques Cousteau was my hero, Captain Nemo was a close second. The bit was set.

After college, I followed in my fathers footsteps and I became employed in the space program as an instructor in the Spaceflight Training Division at NASA. However, today would be different. Far from the classes and simulators back at the Johnson Space Center, I would leave the surface for the depths below to live aboard an amazing underwater habitat called " Aquarius."

Like the space shuttle and space station, Aquarius is an amazing place to live and learn. It provides a unique opportunity to conduct research in an alien environment and hopefully help others realize the fragility, the beauty, and the significance of this ocean environment.

Today, the crew: myself, Mike Lopez-Alegria, Mike Gernhardt and Dr. Dave Williams began our 7-day mission in our new home. Our objective is to live and work in this unique facility and document all of the ways that it is an analog for spaceflight. In other words, to see how much living under water is like living in space. Although at first that may seem strange, after all we are 50 feet under water and the space station orbits 220 miles above, there are many similarities. Both are located in " extreme" environments. These are places that a human cannot survive without great care and caution. Just as the space station, orbiting in the vacuum of space is the "lifeboat" for the astronauts to live and breathe, "Aquarius" provides the same safe environment for aquanauts on the seafloor. The astronauts are bound to their space vehicle and we are bound to ours. While most divers are taught that the surface is our friend, just the opposite holds true for us. As aquanauts, we cannot rise to the surface because our bodies have undergone a significant physiological change. During this change, we have taken on large amounts of nitrogen into our body tissues. To come to the surface at the end of our mission we will have to go through a 17 hour process called decompression, which will rid our bodies of this excess nitrogen.