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The Descent of Alvin

In  forty years of operation, the deep submergence vehicle Alvin has evolved and changed its look several times (oldest version at the top right, current version at bottom left, and a future conception of the next Alvin vehicle at the bottom right). In fact, the sub has been completely disassembled (see movies at the top of linked page) every three to five years so engineers can inspect every last bolt, filter, pump, valve, circuit, tube, wire, light, and battery—all of which have been replaced at least once in the sub’s lifetime. In all of those years and iterations, though, the venerable sub has never done what it did yesterday–place a call to the International Space Station. (Illustration by E. Paul Oberlander, Woods Hole Oceanographic Institution)