Jon Kitzmiller, an expert in electromechanical systems at the University of Texas, who worked on an earlier railgun project, says that the navy team is “going to have considerable difficulty getting [to 64 megajoules], but it’s certainly achievable.” He says that the navy’s budget of $40 million a year secured through 2011 proves that it is serious about making the gun a reality in the next 15 to 20 years. The previous effort was derailed by funding constraints.
One of the biggest challenges, says Kitzmiller, will be in designing a power supply that can handle multiple shots. “In order to store multiple 64-megajoule shots on a capacitor bank, you would need an aircraft carrier full of capacitor banks,” he says. One solution, Kitzmiller and Garnett agree, is a system of rotating pulsed alternators, called compulsators, rather than traditional capacitors.
Other challenges include developing a projectile guidance system that can withstand 40,000 gs–twice the acceleration of current systems–and building a gun barrel that can withstand the force and heat produced by repeated firings. The same force that drives the bullet out of the barrel also tears the rails apart. The Dahlgren prototype looks nothing like a typical gun, and parts will frequently have to be replaced.
“Firing a gun once or twice [makes it] a novelty,” says Garnett. “Firing it a thousand times [makes it] a weapon.”