High Quality Content by WIKIPEDIA articles! USS Angel Shark (SSGN-559), a fictitious submarine apparently named for the angel shark, was the subject of an episode of the television show JAG. Her "SSGN" designation indicates a cruise-missile submarine with a nuclear propulsion plant. In the JAG story, Angel Shark was lost while on a cable-tapping espionage mission in the Sea of Okhotsk reminiscent of those actually carried out by Parche (SSN-683), under mysterious conditions reminiscent of the loss of Scorpion (SSN-589), and involving a secret recovery operation reminiscent of Project Jennifer. No vessel of the United States Navy has ever been named Angel Shark and no vessel has ever been designated SSGN-559. The number indicates an extremely early vessel first nuclear submarine was Nautilus (SSN-571) and the first American SSGN was Halibut (SSGN-587). Construction of SS-559 was authorized during World War II, but was cancelled on 7 January 1946 before the vessel was named.