An Underwater Ice Station Zebra
The Trieste II (DSV-1), the Navy’s most advanced deep sea submersible at the time, surfaced about 350 miles north of the Hawaiian Islands in the pre-dawn hours of 26 April 1972 after recovering a mysterious item.
Publicly called a “data package,” the object was actually part of a U.S. spy satellite, codenamed HEXAGON. Before today’s digital technology, photoreconnaissance satellites used film, which returned to Earth in capsules ejected from the satellite. The capsules, called “buckets,” reentered Earth’s atmosphere and deployed a parachute to slow their descent.
During the first HEXAGON mission in 1971, the parachute broke off causing the bucket to crash into the ocean. This release includes photos of the capsule on the ocean floor, pictures of the Trieste II (DSV-1), and an article recounting the deepest undersea salvage then attempted. We also linked to the Naval Undersea Museum, where the Trieste II (DSV-1) is on permanent display.