Project Azorian (also called "Jennifer" by the press after its Top Secret Security Compartment) was a U.S. Central Intelligence Agency (CIA) project to recover the sunken Soviet submarine K-129 from the Pacific Ocean floor in 1974 using the purpose-built ship Hughes Glomar Explorer. The 1968 sinking of K-129 occurred approximately northwest of Hawaii. Project Azorian was one of the most complex, expensive, and secretive intelligence operations of the Cold War at a cost of about $800 million, or $ billion today.
The US designed the recovery ship and its lifting cradle using concepts developed with Global Marine (see Project Mohole) that used their precision stability equipment to keep the ship nearly stationary above the target while lowering nearly of pipe. They worked with scientists to develop methods for preserving paper that had been underwater for years in hopes of being able to recover and read the submarine's codebooks. The reasons that this project was undertaken included the recovery of an intact R-21 nuclear missile and cryptological documents and equipment.
The Soviet Union was unable to locate K-129, but the US knew where to look, based on data recorded by four Air Force Technical Applications Center (AFTAC) sites and the Adak Sound Surveillance System (SOSUS) array. The US identified an acoustic event on March 8 that likely originated from an explosion aboard the submarine. The US zeroed in on the location to within . The submarine located the boat using the Fish, a towed, , collection of cameras, strobe lights, and sonar that was built to withstand extreme depths. The recovery operation in international waters about six years later used mining for manganese nodules as its cover. The company was nominally owned by Howard Hughes, secretly backed by the CIA, who had paid for the construction of the Hughes Glomar Explorer. The ship recovered a portion of K-129, but a mechanical failure in the grapple caused two-thirds of the recovered section to break off during recovery.
The wreck of K-129
In April 1968, Soviet Pacific Fleet surface and air assets were observed conducting a surge deployment to the North Pacific Ocean that involved some unusual search operations. The activity was evaluated by the United States Office of Naval Intelligence (ONI) as a possible reaction to the loss of a Soviet submarine. Soviet surface ship searches were centered on a location known to be associated with Soviet Golf II-class strategic ballistic missile (SSB) diesel submarine patrol routes. These submarines carried three nuclear missiles in an extended sail/conning tower, and routinely deployed within missile range of the US west coast. After weeks of searching, the Soviets were unable to locate the sunken boat, and Soviet Pacific Fleet operations gradually returned to normal.
The American SOSUS hydrophone network in the northern Pacific was tasked with reviewing its recordings in the hope of detecting an implosion (or explosion) related to such a loss. The Navy analyzed acoustic data from four AFTAC sites and the Adak, Alaska SOSUS array, locating the wreck of the submarine to within . The site was hundreds of miles away from the Soviet Navy search area.
Naval Facility (NAVFAC) Point Sur, south of Monterey, California, was able to isolate a sonic signature on its low-frequency array recordings of an implosion event that had occurred on March 8, 1968. Using NavFac Point Sur's date and time of the event, NavFac Adak and the US West Coast NAVFAC were also able to isolate the acoustic event. With five SOSUS lines-of-bearing, Naval Intelligence was able to localize the site of the K-129 wreck to the vicinity of 40.1° N latitude and 179.9° E longitude (close to the International Date Line).
In July 1968, the United States Navy initiated "Operation Sand Dollar" with the deployment of from Pearl Harbor to the wreck site. Sand Dollar's objective was to find and photograph K-129. In 1968 Halibut, which had been configured to use deep submergence search equipment, was the only such specially-equipped submarine then in US inventory. Halibut located the wreck after three weeks of visual search using robotic remote-controlled cameras. (It took almost five months of search to find the wreck of the US nuclear-powered submarine in the Atlantic, also in 1968). Halibut is reported to have spent the next several weeks taking over 20,000 closeup photos of every aspect of the K-129 wreck, a feat for which Halibut received a special classified Presidential Unit Citation signed by Lyndon B. Johnson in 1968.