Directed energy weapons would be ideal for countering many of the anti-access, area-denial threats that peer nations pose to the United States in wartime, but technology has not progressed to the point where those weapons are operationally useful, the Pentagon’s chief weapons buyer said Tuesday.
Since the U.S. military in 1991 demonstrated the capability of its precision munitions during the first Gulf War, potential competitors like China, Russia and Iran have invested in similar systems, Undersecretary of Defense for Acquisition, Technology and Logistics (AT&L) Frank Kendall said at the Center for Strategic and Budgetary Assessments (CSBA) and Booz Allen Hamilton [BAH] Directed Energy Summit outside Washington.
“The problems that we are facing are the very problems that directed energy systems have been envisioned as addressing for a long, long time,” Kendall said. “In particular, precision missiles, cruise and ballistic.”
Sophisticated ballistic and cruise missiles have become less expensive and have, therefore, proliferated to less advanced countries and non-state actors. That proliferation makes U.S. ships and ground forces vulnerable to attack and defending against missiles with terminal guidance using missile interceptors is prohibitively expensive, he said.
“What China is buying, or well on their way to buying, is a suite of capabilities designed to keep us out of their part of the world,” Kendall said. That includes anti-ship missiles that would keep U.S. amphibious assault vessels too far offshore to launch Marines or aircraft carriers to launch air strikes in the event of a forced invasion, hence ‘anti-access, area denial.’
“Air defenses are something we haven’t focused on in recent years, because we tend to control the air,” he said. In 1991, the U.S. was safely atop the technological heap with its monopoly on precision munitions technology. The world of missile technology is now much more level, Kendall said.
Instead of buying “fairly low numbers of very expensive things” that gave the U.S a decisive technological advantage in past conflicts, “the idea now is to buy fairly large number of inexpensive things and use them in a different way,” Kendall said.
Whereas conventional anti-missile interceptors can cost hundreds of thousands, if not millions of dollars apiece, a single shot from the laser weapons system (LaWS) cost about a dollar. Laser weapons also let commanders dial up or down the intensity of the shot to deal with threats of varying lethality, giving them the ability to “deter, disable or destroy,” a target with a single system.
There are major technological hurdles that need to be overcome before lasers or high-powered microwave weapons are able to destroy an incoming missile in flight, however. The main challenges involve the size, weight and power requirements for current systems.
The Navy is 2012 mounted a prototype laser on a destroyer and demonstrated the ability to shoot down a “soft drone” – one without weapons or countermeasures – during an exercise on a clear, cloudless day. Last year, LaWS, a similar system, was made operational and deployed aboard the USS Ponce afloat forward staging base in the Arabian Gulf.
Scaling the system up to a higher intensity could flip the cost-of-defense paradigm of defending against relatively inexpensive, highly sophisticated anti-ship missiles back in favor of the US, said Navy Secretary Ray Mabus.
“From these successes, I recognized the potential utility and cost-effectiveness of directed energy weapons across the full range of military operations,” Navy Secretary Ray Mabus said at the summit.
That system still requires massive equipment to provide power and cool the laser. Those subsystems, though still fairly inexpensive compared to traditional munitions, are often three to four times the size of the actual laser, said Rich Bagnell, who manages the self-protect high-energy laser demonstration at the Air Force Research Laboratory’s directed energy directorate.
“I believe we have much of the technology in hand, or nearly in hand, for us to be able to handle the self-defense mission,” he said. “The laser is no longer the long goal. It’s power and thermal. … We have a lot of work to do on the subsystems.”
LaWS and other laser weapons in operation, like the Marine Corps’ ground-based area defense laser, operate at about 30 kilowatts of energy. In order for a laser to effectively “kill” incoming missiles it needs to emit about 100-150 kilowatts, Bagnell said.
The Office of Naval Research is feeding lessons from USS Ponce into the Navy’s solid state laser (SSL) technology maturation program, which is aiming to produce a 100-150 kilowatt laser prototype for at-sea testing in 2018. The Navy, in the meantime, has decided to extend the LaWS deployment indefinitely.
Because Navy ships are large and have huge turbine or nuclear powerplants, Mabus said the service is the perfect host for large directed energy prototypes.
The Navy is “best-positioned to address these obstacles right now,” he said. “The size, weight, power, and cooling required by contemporary directed energy systems makes naval vessels the platform of choice for operationalizing the technology. Our ships are big enough to host large, heavy weapons, our gas turbines and nuclear reactors can provide the magnitude of power necessary to make these weapons effective and we have all the saltwater in the world and the air in its atmosphere for cooling.”
Energy could also soon replace traditional explosive propellents that are heavy, take up space and are volatile aboard ship. The Navy’s electromagnetic rail gun, after decades of overhyped, underdelivered promise, is nearing fruition.
“The railgun has been a long time coming,” Mabus said. The service already has successfully tested a 32-joule prototype that can hurl a metal projectile with the power of 11 pounds of C4, which translates to a 23-pound projectile accelerating from 0 to 5,000 miles per hour – seven times the speed of sound – in 1/1000th of a second and can strike targets as ranges up to 100 miles.
“As a point of comparison, the Navy’s current 5-inch gun has a range of 13 miles, its rounds weigh 100 pounds, and their explosive nature makes them more precarious to store and handle,” Mabus said.
In 2015, the Navy will mount a similar weapon aboard a joint high speed vessel, the USNS Trenton, to gauge its operational utility at sea. Plans are to fire 20 projectiles at targets 25 to 50 miles out.