The Navy Is Firing a Mysterious Weapon Today. It Sure Sounds Like a Railgun.

Kyle Mizokami

Popular Mechanics

Tue, December 1, 2020, 8:45 AM EST

From Popular Mechanics

  • The Navy has issued a noise advisory for the Chesapeake region in Virginia.
  • The danger zone stretches nearly six miles toward the Atlantic Ocean, and will be closed to private boat traffic.
  • The Navy hasn’t said what it’s testing, but this is the same location where the service tested its railgun prototypes.

The U.S. Navy is testing something big and loud over the Potomac River this week. The service just issued an advisory over “munitions testing” in Virginia’s Tidewater region, closing sections of the river to boat traffic and warning that civilians could hear loud noises. The projected source of the loud noises is the same range where the service first tested its experimental railgun.

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The advisory, published by Naval Surface Warfare Center, Dahlgren Division and republished by Maryland’s The Bay, states, “NSWCDD plans to conduct range testing, Tues. – Fri., Dec. 1-4 from 8 a.m. to 5 p.m. that may produce very loud noise in communities surrounding Naval Support Facility Dahlgren.” The Twitter user @lfx160219 also posted the advisory:


NSWC Dahlgren warns of “loud” noises on Tuesday, December 1, on the eastern side of the site and downrange. The Potomac River will be restricted to naval traffic for 10,000 yards downrange, or a distance of 5.68 miles.

Things apparently ramp up Wednesday and Thursday, with the noise advisory increasing to “very loud.” On Wednesday, the closed section of the river briefly ramps up to 15,000 yards, or 8.5 miles, before dropping back to 5.68 miles. The testing continues through Friday, December 4. Make your boating plans in the Chesapeake accordingly.

What is this mysterious munition? The advisory doesn’t say, but it does reveal the test is taking place at Dahlgren’s “Railgun Building 1410.”

Photo credit: Time Life Pictures - Getty Images
Photo credit: Time Life Pictures – Getty Images

The main suspect in this case is, of course, a railgun. Long the dream of science fiction, railguns use electricity to generate very strong electromagnetic fields between two rails. A conductive metal device called an armature picks up a projectile and accelerates down the path between the rails, sending the projectile whizzing downrange.

The railgun spits out the projectile at a speed of 4,474 miles per hour, or 1.2 miles per second. According to NASA, the railgun can fire kinetic energy projectiles against aerial targets and high-explosive projectiles against “water surface targets,” a.k.a. ships.