On 6 March 2009, an era in Navy undersea operations ended when the Deep Submersible Rescue Vehicle Mystic (DSRV-1) was retired at San Diego. With that event, more than a half-century of U.S. Navy manned deep submersible operations was over.
The Navy's first manned vehicle was the bathyscaph Trieste. Built in 1953, it was purchased from Professor Auguste Piccard of Switzerland in early 1958. At the time it was one of only two deep submersibles in the world. The French Navy had a modified version of a Piccard bathyscaph, the FNRS-3.
In December 1958, the Trieste made its first ocean dive off San Diego to a modest depth of 820 feet. A year later it dove to nearly seven miles.