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IMAGE: Aquanaut Mike Gernhardt

Aquanaut Mike Gernhardt outside Aquarius.

*NEEMO 1 Journals
*Aquanaut Profile: Mike Gernhardt

NEEMO Journals

NEEMO 1, Mike Gernhardt
Day 7, Saturday, Oct. 27, 2001

Diving in the terminator

The terminator is the line between day and night on a moon or a planet. Everyone recognizes the moon's terminator in the familiar phases of the moon. The earth's terminator is less well know, but can be seen very clearly when viewed from space. In the space shuttle we move at over 17500 miles per hour and pass through the terminator in a matter of less than a minute. I remember going through the terminator on my first space walk. I was up on the end of the robot arm at night with the payload bay lights of the shuttle turned off. I could see the stars clearer than I ever imagined. I could also see Jupiter and it's four moons with my naked eye. Then looking down, a fine line of white light on the wing, pink cloud tops in the gray dawn, a crescent of blue, and a few moments later the luminous jewel blue earth hanging in black space. We were crossing over Florida, when the earth lit up and seconds later over the Bahamas with the turquoise water of the shelf and the cobalt blue of the tongue of the ocean. In my minds eye I pictured being on the reef and looking up over the wall at the silhouettes of fish moving through the deep blue. It was a very intense experience, and then the radio crackled in my ear and it was time to get back to work on the space walk. Before I went to sleep that night I wrote a short poem about my experience in the terminator. I don't remember it exactly but it went something like:

Floating in the terminator
In the instant,
Before sunset
In the moment,
Before sunrise
In between,
Night and day
Light and dark
Life and Death

Where above, concentric rings of color fade into the vast empty blackness and below the earth is transformed into soft soothing shades of gray, where all things are possible:

Time to,
Take a chance,
Step out,
Into the light or Dark,
And to,
Live or Die

This morning we made a terminator dive. Something I used to do when I worked in the Islands years ago. We entered the water at nighttime and watched the earth move from night through the terminator into daylight, from the underwater perspective. It takes about 90 minutes to 2 hrs to see the full transformation. When we left the habitat at 0630 it was dark, looking back we could see the Aquarius and the soft beacons of light emanating from the portholes and the external lights. As we headed out the S4 line into the dark and away from the glow of the habitat, we could see the surface. The water was clear, the moonlight illuminated the surface, and the gentle ocean swells were rhythmically rolling through the moonbeams. We watched fish starting to wake up and lazily swimming in the water column.

Then it was back to the wet porch to drop off water samples and then next out to the Pinnacle to finish up the coral reef measurements. By the time we arrived at the Pinnacle way station checked in with Aquarius, it was gray on the reef. Gray water, gray reef, gray fish, it reminded me of the soft gray tones of the clouds viewed from the terminator in space. We set about making the coral measurements off the transect lines, occasionally taking a moment to look at the surface and for a short time we could see the sun rising in the east and the moon setting in the west. Then back to work. We returned to the way station to re-fill our tanks and the moon was gone and the sun's rays were filtering in at an oblique angle. We watched our bubbles silently rise in formation. We did not use the through water communication system today, so it was silent except for the soothing sound of breathing through regulators.

We finished the measurements and then began picking up the gear. The water turned blue and the fish were awake and feeding. A school of rainbow parrotfish swam by and then undulated away with their eyes rolling. Large Schools of barracuda swam in formation within the water column feeding on silver sided baitfish - probably bogas but these small fish are sometimes tough to identify. We recovered the transect gear and headed back to the habitat with about 30 minutes left on our excursion limits. After we unloaded the gear in the wet porch we had about 15 minutes to lay back and soak up the experience. The water was clear and the sun had transformed from individual yellow rays filtering through the deep blue, to a bright gleaming silver surface. The fish were silhouetted against the rolling waves that sparkled in the morning sun. Our bottom time was nearing its end and we had to return to the wet porch. I refilled my tank but before taking it off I put my mask back on briefly, and submerged again to look out from the wet porch one last time. I didn't want to leave, seven days are not enough.

Curator: Kim Dismukes | Responsible NASA Official: John Ira Petty | Updated: 06/09/2003
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