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Trieste II
Deep Submergence Vessel Trieste II. In 1972 the Trieste II successfully recovered a lost film-return vehicle from the first KH-9 HEXAGON reconnaissance satellite. The frame visible at the front of the vehicle at left was used for towing the submersible, but also could carry equipment down to the ocean floor, such as the claw-like device used to recover the sunken spysat bucket. (credit: US Navy)

Deep ops

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In April 1972 the Deep Submergence Vehicle Trieste II, operating on a secret mission, recovered a film-return capsule from the first, top-secret mission of a KH-9 HEXAGON reconnaissance satellite from 16,400 feet (5,000 meters) below the Pacific Ocean.

The HEXAGON was a massive spacecraft, as big as a bus. (See “A paler shade of black” The Space Review, September 20, 2010; and “Black Fire: De-orbiting spysats during the Cold War” The Space Review, October 25, 2010.) When it launched from Vandenberg Air Force Base atop a Titan III rocket in June 1971, it carried four of the large Satellite Recovery Vehicles (SRV), each the size of the cabin of a Volkswagen Beetle. The SRVs collected the film after it had run through the cameras at high speed. Each SRV had takeup wheels for film from the two main cameras as big as truck tires.

Something went wrong with one of the reentry vehicles from this first KH-9 mission. It is unclear which of the vehicles it was, and what exactly went wrong, but the capsule plummeted to the ocean.

When an SRV was full, the film was cut and the SRV sealed up. It then ejected off the spacecraft in low Earth orbit and retrorockets slowed it down enough so that it reentered the atmosphere over the northern Pacific. The vehicles used an ablative heat shield and after getting through the hottest part of the reentry, they ejected the heat shield and deployed a parachute. Behind the heat shield was a rounded, kettle-shaped container called a “bucket” that held the actual film. The bucket was heavy—at least several hundred pounds for the early missions and possibly up to 2,000 pounds (900 kilograms) for later missions—and it swung under a large parachute.

As all of this was happening a fleet of aircraft launched out of Hickham Field on Oahu was heading into position over the Pacific, northwest of the Hawaiian island chain. What happened next was like an idea out of a James Bond movie: an Air Force C-130, trailing a cable between two poles sticking out of the back of the airplane, flew over the top of the parachute. Because the parachutes were so big, they could not be captured between the two poles, so they were equipped with what looked like a nipple at the top that was small enough to fit between the poles, and it was snagged by the steel cable behind the airplane. The parachute collapsed, and the heavy capsule trailed hundreds of feet behind the plane. Pilots have said that when they caught the really big ones, the buckets that were full of film, their C-130 Hercules aircraft jerked with the weight. A sergeant in the noisy open cargo bay of the plane would then start winching in the cable, and the very heavy bucket with its precious cargo.

But something went wrong with one of the reentry vehicles from this first KH-9 mission. It is unclear which of the vehicles it was, and what exactly went wrong, but the capsule plummeted to the ocean. Perhaps the parachute never properly deployed, or perhaps the plane hit it and collapsed the chute. It seems unlikely that the problem was a simple miss, since the Air Force deployed multiple planes in just such an eventuality. No matter what the cause, the bucket ended up in the water. And it sank.

It finally hit bottom over three miles (five kilometers) down.

What followed was a secret mission involving the Trieste II and her two support vessels, the floating dry dock White Sands and the fleet tug Apache. In November 1971 the Apache towed the White Sands with Trieste II to a location approximately 300 nautical miles (550 kilometers) from Oahu, smack dab in the middle of the SRV reentry footprint, 25 degrees North by 167 degrees West. The White Sands flooded her dock and partially submerged into the ocean. This allowed the Trieste II to float out and then submerge.

The Trieste II was the world’s deepest-diving submersible, daughter of the Trieste, which had descended into the deepest spot on Earth, the Mariana Trench, in 1960. She was not really much of a submarine, because she lacked the ability to maneuver very much. For the most part she went up and down, and that was it. But during this dive the Trieste II apparently went down to the bottom and located the KH-9’s bucket. How exactly she did this is still unknown, but it is possible that the bucket was equipped with an underwater noisemaker similar to that used on aircraft data recorders—also known as “black boxes”—so they can be located at sea. But Trieste II returned to the surface without the bucket and its load of precious film.

A few months later the ships received a Meritorious Unit Commendation from the Secretary of the Navy for “the deepest navigation, search and recovery operation in the world.”

In April 1972 Apache, White Sands, and Trieste II returned to the same location, using what the Navy referred to as “sophisticated surface navigation equipment” that put them in the exact same spot as before. They had to be right on top of it, because Trieste II could not exactly travel very far to locate it. This time, though, they brought with them an additional device, a large mechanical claw, with four prongs. It was about the size and shape of the kinds of claws used in automobile junkyards to pick up old cars by their tops, except it was intended for a much more delicate mission.

The Trieste II submerged and went to the bottom 16,400 feet down. At the front of the Trieste II was a special frame that held the claw in place. The claw was attached to a short cable and above the cable were flotation bladders. Trieste II maneuvered the claw over the bucket and closed it, trapping it. Then the submersible let it go, and the bladders started to rise up, towing the bucket below them, all the way to the surface, where a crane from the White Sands lifted the bucket onto deck.

A few months later the Trieste II, White Sands, and USS Apache received a Meritorious Unit Commendation from the Secretary of the Navy for “the deepest navigation, search and recovery operation in the world.” It stated that they had “recovered a research instrument from the ocean floor at a greater depth than previously recorded.” The commendation stated that the officers and men “upheld the highest tradition of the United States Naval Service.”

A few of the facts of this effort are reported in Project Azorian, by Norman Polmar and Michael White, a fascinating book which is mostly focused on the story of the Glomar Explorer and the recovery of part of the Soviet submarine K-129. But there are many more details that will hopefully emerge from the depths of secrecy if the KH-9 program is declassified in the coming year.