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Images: Building the Next-Generation Alvin Submersible

Titanium used to forge the new personnel sphere started out as barrel-shaped ingots fabricated by a mill in Pennsylvania. The two larger ingots, each weighing 17,000 pounds, were shaped into hemispheres and will be joined to create the crew compartment. The third ingot, weighing 7,000 pounds, will be used to make viewport and hatch inserts.

(Photo by Ben "BK" Miller, Southwest Research Institute)

This summer, at a forging plant in Wisconsin, the titanium ingots were heated to 1,700°F and “edge rolled” to get it them as close to circular as possible. Next, they were paddled to flatten their diameter to 130 inches and to reduce their thickness to approximately 6 inches. (Photo courtesy of the Advanced Imaging & Visualization Laboratory, Woods Hole Oceanographic Institution)

The heated titanium disc is shaped into a hemisphere. (Photo courtesy of the Advanced Imaging & Visualization Laboratory, Woods Hole Oceanographic Institution)

One of the forged hemispheres cools. In years ahead, engineers in California and Texas will remove material from the hemishphere's interiors and exteriors to reduce its thickness to 3 inches. (Photo courtesy of the Advanced Imaging & Visualization Laboratory, Woods Hole Oceanographic Institution)

“This sphere is definitely the biggest technical challenge of the project,” said Anthony Tarantino, part of a team of engineers at WHOI overseeing the development of the upgraded submersible. He holds a model of the new personnel sphere, which will measure 7 feet in diameter. (Photo by Tom Kleindinst, Woods Hole Oceanographic Institution)

Researchers want more time in Alvin during each deep-sea dive, which means generating more power. Fortunately, small, powerful lithium-ion batteries have become common. In fact, those types of batteries could power the new submersible. But instead of one or two thumb-size batteries typically used in a cell phone, it would take about 10,000 in total, said engineer Daniel Gómez-Ibáñez. (Photo by Tom Kleindinst, Woods Hole Oceanographic Institution)

To keep the submersible buoyant, engineers use syntactic foam, a matrix of billions of microscopic hollow glass spheres embedded in a hard epoxy resin. The resulting material is hard enough to resist crushing under extreme pressure, yet it is lighter than water and thus provides buoyancy to lift a 36,000-pound vehicle, said Rod Catanach, a WHOI engineer overseeing the foam’s development. (Photo by Tom Kleindinst, Woods Hole Oceanographic Institution)