Alvin is the United States' only deep-diving manned submersible used for science, so its upgrades will have a serious impact on the discoveries we can pull off in the deep.

To make a tricked-out sub, engineers first had to build a new personnel sphere, the titanium orb that protects the sub's three passengers—one pilot, two scientists—from the crushing pressure of the water above them. Metalworkers cast two perfect hemispheres, 6 feet in diameter, and welded them together with an electron beam. Structural tests showed the sphere was safe to dive up to 6,500 meters below the surface, which opens up 98 percent of the seafloor to exploration.

After the sphere was finished, engineers built a new chasse around it, outfitted with improved tech for the scientists inside. Five HD cameras—up from three on Alvin's previous iteration—record the scene for later analysis. Those cameras can see further, too, thanks to the high-intensity LEDs that ring the sub. And more and larger viewports provide overlapping fields of view, which allow scientists and pilots to coordinate sample collection with the sub's robotic arms.