More than 200 U.S. personnel, three aircraft and a Navy research ship participated in rescue and recovery operations east of Patagonia, with a search area of more than 655 square nautical miles, according to a statement from U.S. Southern Command. The total search area was about 300,000 square miles divided among more than a dozen countries, according to a graphic from the Argentine Navy. Balbi likened the scope of the mission to searching for a cigarette on a soccer field.
The U.S. Navy deployed a P-8 Poseidon reconnaissance aircraft within a day of the incident, said Cmdr. Erik Reynolds, a Navy spokesman. It was later joined by an additional P-8, a NASA P-3 Orion research aircraft stocked with powerful scientific instruments. Multiple unmanned underwater mapping and salvage vehicles were also used.
A small team will remain in Argentina until Jan. 2, and after that, technical assistance will be provided by experts back in the United States, Reynolds said.
The hopes of family members and rescuers were repeatedly dashed after what seemed to be promising signs of life turned out to be mistakes or false assumptions. Sonar pings picked up early in the mission were believed to be metallic, but Argentine officials later said they were biological in nature. In another instance, a life raft and white signal flares were seen in the ocean. They were both found to be unconnected to the San Juan, which had green and red flares, officials said.
A network of oceanographic scientists recorded a “hydro-acoustic anomaly” three hours after the last communication with the San Juan, near its last known position, Reynolds said. The Comprehensive Nuclear-Test-Ban Treaty Organization, a group that tracks underwater seismic events to determine if they are related to nuclear testing, raised the possibility that the event could have been an explosion.
Defense Minister Oscar Aguad sacked Adm. Marcelo Srur, the head of the Argentine Navy, after an investigation of the incident, the Associated Press reported.
Submarine recovery missions are rare. The last time U.S. resources were dispatched was in August 2005, when the Russian mini-sub Priz AS-28 was entangled in nets and cables during a training mission across the Bering Sea. Though U.S. assets were deployed, the U.K.’s Royal Navy Submarine Rescue Service arrived first, Reynolds said, and rescued all seven of the crew.
Every U.S. military operation ends with an after-action review to determine what went right and wrong. That process still has not occurred for the San Juan recovery mission, Reynolds said, although lessons will probably revolve around search techniques, equipment deployment and ways to improve coordination with foreign militaries.
“It’s easy to give your hopes up from a false lead,” Reynolds said, speaking for himself as a spokesman. “You have to be cautious; don’t get too excited over something that turns out to be a ghost.”