In the mid-1990s, someone at the Pentagon came up with a novel solution to a vexing problem: how to shoot down enemy missiles when they are most vulnerable, well before they approach their targets. The answer: Mount a powerful laser on a modified Boeing 747 that can zap missiles in their boost phase, when they are slowly lifting off and laden with fuel.
The Airborne Laser was eight years behind schedule and $4 billion over budget when then–Defense Secretary Robert Gates decided that the whole notion of a 747 flying lazy circles in the skies near a potential adversary, waiting for a possible missile launch, was prohibitively expensive and totally impractical.
In canceling the program, Gates dryly noted that he didn’t “know anybody at the Department of Defense who thinks that this program should, or would, ever be operationally deployed.”
The Airborne Laser, it turned out, was a bit ahead of its time.
The ABL’s unwieldy chemical megawatt laser, which was so heavy it could be carried only by a plane the size of a 747, has now been supplanted by a new generation of smaller solid-state kilowatt lasers, which may do for the ABL what breakthroughs in lithium-ion battery technology did for electric cars in terms of feasibility.
One threat that worries Michael Griffin, the Pentagon’s point man for research and engineering, is drones, which are commercially available and can be coordinated to attack in swarms. Think of last year’s opening ceremony at the Olympic Games in South Korea, when 1,200 Shooting Star drones made by Intel wowed spectators by flying in unison to form animated images in the sky. Now imagine swarms of angry drones overwhelming U.S. troops with small hand grenade-sized explosives.
“The idea of swarming attacks is certainly a concern, and it may be a transformative concern,” said Griffin at the Center for Strategic and International Studies last November. “We need to learn how to defend against such things, and we need to learn how to perpetrate our own versions of those.”
The smaller, lower-powered ABL is uniquely suited to counter the threat from drone swarms.
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Late last year, at a test site on White Sands Missile Range, the Air Force used both lasers and high-powered microwaves to shoot down small, unmanned quadcopters. Among the observers was Mark Neice, executive director for the Directed Energy Professional Society, who once worked on the Airborne Laser project.
“The laser system puts a spot about the size of a quarter on the unmanned system, and it’s designed to burn through the outer hull and get into either the avionics or the engine, thereby disabling the platform and causing it to fall to the ground,” Neice said.
“The HPM [high-power microwave] system uses a high-power radio frequency, kind of in a broader sweep that allows that to then interface with the electrical equipment on board the [drone] and either cause it to mission abort or fall to the ground,” he explained.
While lasers require a line of sight to burn or blind enemy drones, microwaves can render a whole swarm inoperable at once.
“We often think about directed energy as large lasers,” said Griffin, “but we also have high-powered microwaves, which can be very effective at what we call an electronics kill. It’s really hard to envision handling swarming attacks by purely kinetic means.”
But lasers, which literally operate at the speed of light, have other advantages.
Laser beams are silent, invisible, and 50,000 times faster than an incoming missile, which means that operators can just point and shoot and don’t have to lead a moving target.
A 2018 Congressional Research Service report noted the “long and complicated history” the U.S. military has in developing directed-energy weapons, but found that some current programs “are beginning to show promise.”
One system, dubbed “LaWS” (Laser Weapon System), was deployed by the Navy in 2017 aboard the USS Ponce, an amphibious transport ship that has since been decommissioned, where the laser demonstrated a capability against not just drones but small boats and aircraft.
Directed-energy weapons have another advantage: Pretty much all the costs are up front in development and testing.
“It’s an expensive technology to buy but an incredibly inexpensive system to operate, because, now that we’ve transitioned to electric lasers, this runs off of diesel fuel, and the cost of the diesel fuel is less than a dollar per engagement,” says Neice.
But there remain technical challenges, and directed-energy weapons are still a few years away “if indeed they ever become practical options,” says the Congressional Research Service report.
“While DE weapons offer a variety of advantages over conventional kinetic weapons including precision, low cost per shot, and scalable effects, there are also some basic constraints such as beam attenuation, limited range, and an inability to be employed against non-line-of-sight targets which will need to be addressed in order to make these weapons effective across the entire spectrum of combat operations,” the CRS report said.
But the Pentagon’s chief futurist is more sanguine. “In my opinion, we are no more than a few years from having, particularly in the laser world, directed-energy weapons of military utility,” said Griffin.
The Pentagon’s Missile Defense Review, released this month, envisions directed-energy weapons to shoot down enemy missiles not only in their boost phase but also in space, much like the Reagan-era “Star Wars” concept abandoned in the 1980s as unworkable.
[Also read: Nine key takeaways from Trump’s Missile Defense Review]
“Much has changed since the United States last considered space-based interceptors,” the report concludes, “including major improvements in technologies applicable to spacebasing and directed energy.”
The report says the Pentagon is currently preparing “a strategic roadmap” for the development and fielding of directed-energy weapons and that funding for high-energy lasers will be included in the president’s fiscal year 2020 budget request, which will be submitted to Congress next month.
