Somewhere in the tropical Pacific, DSV Alvin crew member Jeff McDonald emerges from the sub’s  hatch, after giving an orientation to a future scientist-observer. Alvin holds three, a pilot and two observers, in a six-foot diameter sphere. The Alvin group conducts orientations to familiarize new passengers with the sub’s restricted space, layout, and systems before they dive. A new sphere is being constructed, part of a major upgrade to Alvin slated to begin in 2011. (Photo by Buffy Cushman-Patz, Teacher at Sea)