Navy test-fires low-cost, hypersonic-speed projectiles

Twenty projectiles were successfully fired at near-hypersonic speed from the USS Dewey's standard Mk 45, five-inch main deck gun during the "Rim of the Pacific" exercises off Hawaii, the USNI News reported.

It was an attempt to learn if the 40-year-old gun's utility could include a high-tech, low-cost weapon against cruise missiles and unmanned aerial vehicles.

In October, the Congressional Research Service said in a report that the new weapon, called an HPV or hypervelocity projectile, was designed for a railgun, a device using electromagnetic force to launch projectiles by means of a sliding armature.

Shot from the deck gun, the payload can travel as fast as Mach 7.4, or over 2,400 mph at sea level. The system is under consideration, as is a laser guided system and the railgun approach.

"Any one of these three new weapons, if successfully developed and deployed, might be regarded as a 'game changer' for defending Navy surface ships," the CRS said. "If two or three of them are successfully developed and deployed, the result might be considered not just a game changer, but a revolution."

The "gun-launched guided projectile," as the Navy has renamed the system tested at the summer exercises, can be fired using existing and aging guns found on many vessels -- making it considerably less expensive than the other systems under examination.

Defensive missiles cost $800,000 to a few million dollars each, and would have to be used in great number to counter incoming salvos of enemy missiles. The gun-fired guided projectiles, however, cost about $85,000 each, the CRS said.

BAE Systems, developers of the HPV, said it can be used by existing Navy, Marine Corps and Army guns.