Don Walsh was a U.S. Navy submarine officer and ocean engineer who, with Jacques Piccard, became one of the first two people to reach Challenger Deep in the Mariana Trench.
Walsh served in submarines and developed expertise in undersea operations before being assigned to the Navy’s bathyscaphe program.
From 1959 to 1962 he served as officer in charge of Trieste at the Navy Electronics Laboratory in San Diego.
Trieste had been designed from Auguste Piccard’s bathyscaphe concept and was acquired by the U.S. Navy in 1958.
For Project Nekton, the vehicle received a stronger pressure sphere capable of withstanding the enormous hydrostatic pressure expected in the Mariana Trench.
On January 23, 1960 Walsh and Jacques Piccard began the descent toward Challenger Deep.
A cracking sound during descent was later associated with damage to an external viewing-window component, but the pressure sphere remained intact.
The bathyscaphe reached the seafloor at roughly 35,800 feet by the period measurements and remained there for about twenty minutes before beginning ascent.
Later improved depth measurements have refined Challenger Deep figures, so TransitSatellite should attach the 1960 depth number to the instrument and source rather than present it as a timeless exact value.
Walsh remained active in ocean engineering, education, and exploration long after the dive.
For TransitSatellite, the achievement must remain a joint Walsh–Piccard mission supported by a large Navy and engineering team—not an individual record attributed to only one occupant.