Raytheon Company has begun deliveries of pulse power containers in support of the U.S. Navy's Railgun program. The containers, which are comprised of multiple pulsed power modules, will be integrated into the Navy's Railgun test range for additional development and testing. The modular pulsed power containers, when combined, produce enough energy to enable the electromagnetic launch of a railgun's high-velocity projectile at speeds in excess of Mach 6.
"Directed energy has the potential to redefine military technology beyond missiles and our pulse power modules and containers will provide the tremendous amount of energy required to power applications like the Navy Railgun," said Colin Whelan, vice president of Advanced Technology for Raytheon's Integrated Defense Systems business. "Raytheon's engineering and manufacturing expertise uniquely position us to support next generation weapon systems to meet the ever-evolving threat."
Raytheon's pulse power container design is the result of work stemming from an initial $10 million contract with Naval Sea Systems Command to develop a pulsed power system, which will enable land or sea-based projectiles to reach great distances without the use of an explosive charge or rocket motor. Raytheon is one of three contractors developing a PPC design for the U.S. Navy.
The Navy started pursuing the railgun as a high-tech addition to the arsenal currently on its warships. First of all, it's fast – the projectile would go from 0 to 5,000 mph in less than a millisecond, striking with such great kinetic energy that no explosive warhead is necessary, U.S. Navy Secretary Ray Mabus said in a June 2015 summit on directed energy.
Next, its round is lighter – 23 pounds, compared to the 70-pound shot that fires from the Navy's current five-inch gun. Lighter, non-explosive ammunition is both easier and safer to carry, meaning Navy fighters can stockpile rounds in greater numbers before shipping out.
The key to the Mach 6 shot isn't just the amount of energy required, but the speed at which the gun releases it. That power is measured in units called megajoules, and the Navy has specified that it wants the railgun to fire a 32-megajoule shot. That's about the same amount of force as 11 pounds of C4 explosives, Mabus said at the energy summit.
To produce that kind of pop, Raytheon has designed what is known as a pulse power container – a 20-foot-long, eight-and-a-half-foot-tall box that holds and connects dozens of smaller units called pulse power modules. The job of each of those modules is to draw in energy over several seconds and release it in an instant. Chain enough of them together, and they crank out enough power to make the Mach 6 shot.
Provided, of course, that they release all that power quickly, said Peter Morico, one of the engineers who worked on the system.
"If you had a 100-watt lightbulb and you sat in front of it 24 hours a day for 12 days, you'd absorb 100 megajoules. You could easily survive that," Morico said. "But release that same amount of energy in 10 milliseconds, and you, your house, your neighbor, your neighbor's house and your neighbor's neighbor's house are gone."
Each module undergoes extensive testing before it graduates to the pulse power container. The test starts with the push of a big green button.
A generator kicks on and the power starts to flow – 60 kilowatts, enough to light up 20 or 30 houses. The module, locked away in a test chamber for safety, drinks in the juice for about five seconds, then spits it out in an instant – directly into a water-filled barrel that absorbs the shock.
“It’s like winding up a big spring for five seconds and letting it go,†Morico said. Except that spring would flap and flail from all the energy. In this test, if it goes well, nothing much happens at all. Only a malfunction such as a power arc would produce the kind of flashes and bangs you might expect from a test of such powerful electronics.
Inside the chamber, two high-definition cameras keep a close watch on the module. They show absolutely nothing happening; the video is so still it's indistinguishable from a photograph. The only noise is a modest pop, like a champagne cork shooting out of a bottle.
And while there's no actual champagne in the test chamber, this noise is both a sign of success and a cause for celebration. “I love that sound,†Morico said.
