Piranha

The payload aboard Iowa, Bastian’s plane, was the reason the three Megafortresses were here.

Stuffed into Iowa’s forward bomb bay were a half-dozen fiberglass and steel container that looked like the old-fashioned milk containers once used to gather milk from cows on the copilot’s family farm. A thick ring that sat about where the handles would have been contained just enough air to properly orient the container’s “head” float a few meters below the surface of the water. Above the ring was a rectangular web of thin wires that, once deployed, would extend precisely 13.4 meters. The wires were attached to a line-of-sight radio transmitter that generated a short-rang signal across a wide range of bands. These signals could be received and processed by a specially modified version of the ante

The bottom portion of the buoy contained three different arrays, the first was designed to broadcast audible signals that sounded like a cross between the clicks of a dolphin and the beeps of a telephone network. The second picked up similar audible transmissions in a very narrow range. The third transmitted and listened for long and extremely-low-frequency (or ELF) radio waves. These devices were actually relatively simple and while not inexpensive, were considered expendable—which was why the buoyant ring was equipped with small charges that would blow it off the buoy, sending them to the bottom of the ocean.

In essence, the milk cans were simply sophisticated transmitting stations for “Piranha,” the larger device strapped to Iowa’s belly. Piranha looked like an oversized torpedo with extra sets of fins on the front and rear. Once in the water, the conical cover on its nose fell off to reveal a cluster of oval and circular sensors that fed temperature, current, and optical information back to a small computer located in the body of the device. Between these sensors and the computer was a ball-shaped container that held a passive sonar; this too fed information to the computer, which in turn transmitted it, whole or in part, back to the buoy. The rear two thirds of Piranha contained its hydrogen-cell engine. Pellets made primarily of sodium hydride were fed into a reaction chamber where they mixed with salt water, creating hydrogen. This part of the engine was based on the hydrogen-powered, long-endurance, low-emission motor that powered an ultra-light UAV being tested at Dreamland. The sea application presented both major advantages—the availability of water allowed the compressed, pelletized fuel to be substituted for a gas system—and great challenges—the fact that it was salt water greatly complicated what was otherwise a fairly simple chemical process.

Rather than turning a propeller as it did in the ultra-light, Piranha’s engine was used to heat and cool a series of alloy co

Piranha had been developed by a joint Navy and Dreamland team; it was represented the next generation of unma

Unlike those probes, Piranha could be operated from aircraft, thanks to the buoy system. Like the buoys, the probe itself was disposable, or would be in the future. For now, a low-power battery mode took it back to a specific GPS point and depth for recovery by submarine or surface ship up to 150 miles from rundown.

The data transmitted back to the buoys—and from them to a controlling airplane or vessel ship—was considerably greater than that possible in the current-generation UUVs, thanks largely to compression techniques that had been pioneered for the Flighthawk. These “rich” signals were difficult to decode and had a short range, which limited the ability of an enemy to detect and track them. in the stealth mode, which used only the intermittent audible mode to communicate, the operator received enough information to identify size, course, and bearings of an enemy target out to seventy-five miles, depending on the water conditions. In “full como,” or communications mode, the signal fed a synthetic sonar system. This sonar was passive, and thus completely undetectable. It painted a three-dimensional sound picture on an operator’s screen; the computer’s ability to interpret and translate the sounds into pictures of the object that created them not only meant that combat decisions could be made quickly, but the operators required considerably less training than traditional sonar experts. Just as the improvements in sensor gear and computers allowed the copilot on a Megafortress to perform the duties of several B-52 crew members, the synthetic sonar would allow a back-seater in a Navy Tomcat to handle Nirvana while taking negative G’s.

In theory, Colonel Bastian and his people were going to find out if the impressive results in static and shallow-water tests could be duplicated in the middle of the ocean, against some of the best people with Seventh Fleet could muster. The Kitty Hawk, steaming out toward Japan after a brief respite at Pearl, was the target.

If you’re going to test a new weapon system, might as well go against the best, thought Dog.

“Piranha Buoy in ten seconds,” said Ferris.

“Ten seconds,” said Dog. “Piranha Team, you ready?” he added, speaking over the interphone circuit to the Piranha specialist, Lieutenant Commander Tommy Delaford and Ensign Gloria English. They were sitting downstairs in what ordinarily was the Flighthawk deck on the Dreamland Megafortresses.

“Ready,” replied Delaford, the project leader for Piranha. Delaford worked directly for the Chief of Naval Operations, Warfare Division; his handpicked Navy team include people from N77 (the submarine warfare division), N775 (science and technology), and the Space and Naval Warfare Systems Command.

“I have Task Force Charlie,” said Captain Derek Teijen, piloting Galatica. “Tapping in coordinates—they’re a bit closer than they’re supposed to be, Colonel. Lead ship is barely one hundred miles away. Have it ID’s as a DDG. Carrier is sending two F-14’s toward us.”