From the Archives

The original personnel sphere of the human-occupied vehicle Alvin was shaped from a steel plate in 1964 at Lukens Steel Co. in Coatesville, Pennsylvania. That sphere was used until 1973, when engineers switched to a titanium sphere that was still in use until the submersible’s recent overhaul and upgrade. Scientists, engineers, technicians, and machinists are constantly at work to keep Alvin at work and up-to-date and recently celebrated a milestone when the sub was re-certified to dive to a depth of 4500 meters (14,800 feet). (Photo courtesy of Woods Hole Oceanographic Institution Archives)