Bathyscaphe Trieste
On 23 January 1960, she reached the ocean floor in the Challenger Deep (the deepest southern part of the Mariana Trench), carrying Jacques Piccard and Don Walsh. This was the first time a vessel, manned or unmanned, had reached the deepest known point of the Earth's oceans. The onboard systems indicated a depth of , although this was revised later to ; fairly recently, more accurate measurements have found Challenger Deep to be between and deep.
Operation Wigwam
Operation Wigwam involved a single test of the Mark 90 Betty nuclear bomb. It was conducted between "Operation Teapot" and "Project 56" on May 14, 1955, about southwest of San Diego, California. 6,800 personnel aboard 30 ships were involved in "Wigwam". The purpose of "Wigwam" was to determine the vulnerability of submarines to deeply detonated nuclear weapons, and to evaluate the feasibility of using such weapons in a combat situation. The task force commander, Admiral John Sylvester, was embarked on the task force flagship . WIGWAM was the first atomic test in the deep ocean, and it remains the only test that has been conducted in water deeper than 1000 ft.
The test device was suspended to a depth of by cable attached to a barge. A tow line connected the 205 ft. (a ) and the shot barge itself. Suspended from the tow lines of other tugs were three miniature unmanned submarines named "Squaws", each packed with cameras and telemetry instruments.