This morning we awoke at 4:30 a.m. since it was our last chance to use the restroom in the entry lock. Once the pressure inside the habitat was equivalent to sea level we were unable to flush the toilet since draining the toilet to the holding tank is done by a differential pressure gradient between the habitat (greater pressure) and the life support buoy (lesser pressure). Bringing the pressure inside the habitat to sea level eliminates the pressure differential meaning we were no longer able to flush the toilet. Despite the challenges of trying to sleep flat on our back with our arms and legs straight, I was able to get a reasonably good nights sleep. We had a lot of work to do helping Ryan and Mark complete the long checklist of items that had to be completed before we could increase the pressure inside the habitat back to 48 feet to allow us to swim back up to the surface.

It reminded me of the "de-orbit prep" phase of preparing to return from space where the crew has to work closely together as a team to complete a long list of tasks before the de-orbit burn. While we cleaned and sorted through the food we picked whatever we wanted for breakfast and to eat while we worked. All of the sheets and bedding from the bunks had to be removed and brought back to the surface for cleaning. After removing the sheets, the mattresses were moved so that the bunks could be cleaned with a special disinfectant solution to reduce the possibility of microbial contamination to the habitat building from one mission to the next. After cleaning the bunk itself we had to wipe down every surface in each part of the habitat. We started adjacent to the bunks wiping down the pressure hull and the compartments adjacent to the bunks where we had been stowing our personal items. This continued into the main lock and finally into the entry lock so that every surface had been wiped by the time we finished. While this was being done we also did an inventory of the food and medical items remaining. The coordinated effort of the four aquanauts and the two habitat technicians resulted in our finishing everything by 7:45. The recompression of the habitat atmosphere to 48 feet was scheduled for 8:30 so we had time for some last minute reflections as the mission was drawing to a close.

Looking out the view ports we saw fish that we now recognized as daily visitors to Aquarius. After we left the habitat they would remain behind, the rightful inhabitants of the reef. Like flying in space this reminded us that while we have the capability to visit both of these extreme, harsh environments, we are only visitors and ultimately must return to the earth's surface. While space flight creates in virtually all astronauts' a recognition of the beauty and fragility of our planet, as an aquanaut I was equally impressed about the fragility and diversity of life on the reef. The time flew by and at 8:20 we headed towards the entry lock and closed the door to the main lock so that we could expedite our return to the sea floor (at this point, at the end of decompression, pressure inside Aquarius was equal to surface pressure - one atmosphere). With a loud rushing sound the pressure surrounding us increased, pushing on our ears and requiring us to equalize early and often. The temperature of the air in the entry lock also increased dramatically with the effects of compression and we found that our voice returned to the same unusual tone that we had become so used to over the course of the mission. The door into the wet porch was opened when the pressure had equalized on both sides and we went out to greet the safety divers that would be helping escort us to the surface.

For the ascent we would not wear our wetsuits or technical diving gear. Rather, we only had our masks and fins, and a small bail-out bottle attached to a regulator that provide us with enough air to breathe to reach the surface. The light filtered down through the turquoise blue water. It sparkled around us sending shimmering reflections off the scales of the barracuda whose omnipresence was now expected when we were diving outside the habitat. We proceeded down the S4 excursion line a short distance before swimming over to the mooring buoy line to slowly head to the surface. Swimming without all of our gear seemed unnatural at first but certainly made me feel freer in comparison to the weight of the twin 100 cu ft tanks we typically used on all of our dives. Approaching the boat we could easily see that our tranquil swim was about to change as the four to six foot sea swells rocked the boat in every direction. The waves raised the stern dive platform that we would have to climb onto well out of the water before it crashed back down beneath the surface. After such a long and successful mission this was not a time to make a mistake and get hurt boarding the boat and I was happy when all of our team made it successfully into the boat without incident.

The mission was over. Yet despite our desires to have stayed longer, we were all happy to be sitting in the boat breathing the fresh sea air and looking at the beautiful blue sky above us. With the white caps and breaking waves it took us longer to get in to shore than normal. As we pulled into the canal Bill stepped forward and congratulated us all on a successful mission. It was truly an honor to have been part of the first NASA/NOAA research mission to the habitat. This was the first NASA underwater habitat mission since the Tektite program over three decades ago and Mike G., Mike L.A. and I felt very fortunate to join the very small group of explorers that have been to both outer space and inner space.

Final Reflections:

I have tried as much as possible to capture the feeling of living and working under the ocean in my journal. One of the many goals of our mission was to evaluate the potential benefit of using the underwater environment to help prepare astronauts for the rigors of long duration space flight. It clearly accomplished that goal. From a personal perspective, it seemed to me that the habitat was the closest thing to a space flight environment that I had experienced on earth. Our crew felt the pressure to succeed with the research goals of our mission just as we do flying in space. I found it personally fulfilling being back in the role of a proxy scientist collecting data to help researchers in their quest for knowledge. The environment, while appearing beautiful and tranquil, is as harsh as outer space and each team member clearly understood that a mistake could have catastrophic consequences. Perhaps though, the lasting personal memory for me comes from experiencing the awe and beauty of exploring these unique environments. I hope that somehow not only will we learn scientifically about these environments, but that we will effectively communicate and share their beauty and the need to protect them for future generations to enjoy.