Navy Can See A More Powerful Future As Its Railgun Test Sets A Record

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Forum Spin Doctor
Norfolk Virginian-Pilot
February 1, 2008 By Matthew Jones, The Virginian-Pilot
Dahlgren, Va.--Science got one step closer to science fiction Thursday morning, when the Navy used an electromagnetic railgun to fire a 7-pound slug at seven times the speed of sound.
The record-breaking shot, witnessed by a roomful of VIPs via remote camera at the Naval Surface Warfare Center, also moved the armed forces further down the road to a faster, safer, lighter, cheaper form of firepower.
Moments before, a split screen showed an engineer at a control panel and a target that stood several miles away.
“Armed,” he said.
Then: thick smoke.
Target gone.
Applause.
After the shot, Adm. Gary Roughead, chief of naval operations and a former gunnery officer, praised the test.
“I never want to see a sailor or Marine in a fair fight,” he said. “I always want them to have the advantage.”
The railgun’s technology is straightforward and potent, making it a long-time favorite of fiction writers and video game makers, though in sometimes fanciful variations, such as a hand-held version in the “Quake” series.
The Navy’s railgun is basically a long tube lined with two copper alloy rails. When charged by an enormous pulse of electricity, these rails exert a tremendous force that sends an inert projectile out at incredible speed.
And the more juice generated, the more muzzle velocity the weapon has and the farther and faster the projectile can go.
Thursday’s test produced a record 10.86 megajoules, which sent the 7-pound aluminum slug at Mach 7 (more than 5,000 mph) for 80 meters, a roughly 20-millisecond ride.
The Navy’s ultimate goal is a ship-mounted weapon capable of firing missiles 200 nautical miles in a six-minute arc into outer space and back to land, guided by GPS.
This dwarfs the range of the Navy’s current workhorse gun, the 5-inch MK 45, which shoots about 13 nautical miles.
The railgun uses electricity to propel its missiles, so they carry no fuel. The damage is caused purely by the kinetic energy of the missiles’ descent, which is projected to reach Mach 5, so they carry no warheads.
This means the missiles are cheaper. They are also smaller and safer, making them easier to store aboard ships and allowing for more variety in a vessel’s design.
For the Marines the gun would support, there are further benefits.
A ship carrying a rail gun would be able to begin bombarding the shore much sooner, far beyond radar range. It also would be able to fire more quickly.
The gun has a projected accuracy of 5 meters, which would minimize risk to Marines on the ground as well as any collateral damage.
But for now, that is still the future.
The present stood several miles from the VIP viewing room, where the railgun awaited its next test.
Along one side of the building, a series of capacitors rose like a two-story hybrid of a transistor radio and 1980s-era computer circuit board.
Cables snaked from these capacitors like oversized distributor cables leading to several dozen gigantic spark plugs mounted at the rear of the 40-ton metal box housing the gun itself.
During the gun’s five-minute priming, these capacitors drew energy from the power grid and stored it like a camera flash.
When fired, the 32-megajoule pulse surged through the wires, creating tremendous force and heat and sending the missile into an outside trap.
Elizabeth D’Andrea, the railgun’s project manager, stood by the gun Thursday and spoke of the challenges still ahead.
These include the extreme wear on the launcher and the projectile, which experiences a force of 40,000 G’s as it leaves the gun, as well as the materials needed for a projectile to handle four minutes in outer space at the apex of its arc.
Another problem comes in shrinking the capacitors to fit aboard a ship, as well as powering and cooling the weapon once it’s aboard, controlling electromagnetic interference and making the entire weapon maneuverable.
The goal, D’Andrea said, is to mount the weapon on a future generation all-electric ship by the year 2025.
At the gun site, Roughead declined to speculate on when the weapon would be ready and on what kind of ship it would be mounted .
“There’s a long way to go,” he said.
There is no cost estimate at this point, said Rear Adm. William Landay III, chief of naval research.
Outside the building, Andrew Wyman, a range test engineer, stood in a three-sided concrete shed. Behind him, a steel box mounted on a railcar held 5,000 pounds of sand.
This was the missile trap and it looked the part: The sand was pushed far back into and up the box’s sides, which splayed out like frozen silver paint.
Nearby lay the tatters of the foamboard target, partially reassembled.
“You’re dealing with lightning and thunder when you shoot this thing,” he said, holding up a small chunk of aluminum, the last of the slug.
The shot Thursday was roughly the 100th since this round of testing began in October 2006, he said. The lab plans to go to six tests a week starting next week.
Nearby stood Roger Ellis, a technical director.
He said the project has attracted a broad spectrum of scientists, with its focus on materials, electricity, mechanics, chemistry and even plasma physics.
“It’s tremendously exciting. We’re making history here,” he said. “This is more than just a paycheck for the engineers working here.”
 
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