Directed-energy weapons are among a handful of maturing disruptive or asymmetric technologies that could confer game-changing technological advantages both as a superior defensive capability and as an effective electronic attack option. For operations in anti-access/area-denial environments, they could strengthen U.S. power projection assets and defend fixed-site installations and/or expeditionary forces from attack. In the Middle East, DE weapons could help enhance force protection against small-boat swarms, unmanned aerial vehicles or rocket, artillery, mortar or missile attack.
Joint doctrine defines directed energy (DE) as an umbrella term covering technologies that produce concentrated electromagnetic energy and atomic or subatomic particles. A DE weapon is a system using DE primarily as a means to incapacitate, damage, disable or destroy enemy equipment, facilities and/or personnel. Directed energy has the potential to yield cost effective weapons that can deliver precise, scalable effects – and at long ranges – with a large magazine capacity.
The electromagnetic spectrum is a critical enabler for modern militaries, As early as In 1956, Soviet Admiral Sergei Gorshkov boldly declared that “the next war will be won by whichever side best exploits the electromagnetic spectrum”. U.S. chief of naval operations, Admiral Jonathan Greenert, had forecasted “in the next two decades, the [electromagnetic] environment may become our most critical warfighting arena.”
The unmatched strategic and operational advantages of U.S. and allied forces for more than four decades is waning as many of the key technologies – precision strike, satellites, stealth and advanced communications, among others – proliferate to others. In September 2014, acting Assistant Secretary of Defense for Research and Engineering Al Shaffer warned that “we have lost the electromagnetic spectrum,” expressing concern publicly over the proliferation of high-powered, low-cost and commercially available electronic warfare equipment.
The report “DIRECTED-ENERGY WEAPONS: Promise and Prospects” by Jason Ellis, a visiting senior fellow at CNAS on leave from Lawrence Livermore National Laboratory, offers an objective assessment of the maturity of directed-energy weapons today and what developments may be possible with continued DOD investment.
Actual directed-energy programs, however, have frequently fallen short of expectations. The Airborne Laser program sought to field a megawatt-class chemical laser aboard a 747 aircraft, with planned forward deployment of a 20- to 40-shot magazine and an initial operational capability by 2010. Its main role was a mobile, rapid-response theater missile defense system, along with neutralizing enemy air defenses and providing an offensive counterspace capability. The Space-Based Laser was conceptualized as a constellation of orbital weapons able to engage and destroy in boost phase missiles launched from any corner of the globe. In the 1990s and early 2000s, billions of dollars were spent on Airrborne Laser and Space-Based Laser programs, both of which ultimately failed to reach maturity.
After a nearly half-century quest, the U.S. military today is on the cusp of finally fielding operationally relevant directed-energy weapons. Current-generation tactical lasers have been demonstrated in realistic operational settings against realistic threats. In 2013, the Navy demonstrated the ability of a ship-based tactical laser to shoot down an enemy drone, a more cost-effective counter to low-cost drones than firing a missile. In November 2014, the Navy demonstrated a laser weapon at sea against enemy small boats, a scalable and cost-effective countermeasure to a dangerous threat.
The Air Force demonstrated in 2012 the feasibility of airborne high-power microwave weapons. The Counter-electronics High-powered Microwave Advanced Missile Project (CHAMP), an air-launched cruise missile with a high-power microwave payload, reportedly successfully engaged a set of electronic targets.
High-energy lasers have been the mainstay of DOD’s directed-energy weapon developments since the 1960s, some chemical lasers, designed for strategic missile defense purposes, have demonstrated megawatt-level output. But the large footprint, complex logistics and various technical challenges associated with chemical lasers eventually led to their cancellation.
Current developmental megawatt-class systems emphasize free-electron and diode pumped alkali laser technologies. More recent developments in solid-state and fiber lasers, designed primarily for tactical engagement, feature lower-power systems designed for forward-deployable platforms. They are effectively meeting technical challenges, including power-scaling, beam quality and thermal management — and packaging.
Radio frequency weapons are principally counterelectronic weapons. Starfish Prime and other Cold War-era tests demonstrated the effects of nuclear EMP on electronics; the more modern explosively and electrically driven high-power microwave devices produce non-nuclear EMP effects.
High-power microwave weapons have proven capable of gigawatt-class power output that can disrupt or even destroy modern electronics, but at comparatively short range, using single-shot, very-high peak- power EMPs. Radio frequency weapons can also use millimeter waves for counter personnel applications such as crowd control or perimeter security.
Over the past decade, the scientific community has made noteworthy progress on high-power microwave technologies. These include improvements in microwave sources, antenna design and other long-standing technical limiters to achieving operationally relevant size, weight and power configurations. This has enhanced system’s power density and extended its effective range, which enhances its operational utility. More recent HPM devices are electrically driven, yielding high-repetition rate, more agile waveforms and greater power output.
They have also improved system’s ability to operate effectively at different frequencies and, therefore, improve performance against varied target types. Taken together, these improvements significantly enhance the probability of a system’s achieving the desired counterelectronic effect. Collectively, such developments serve to reduce an HPM system’s physical footprint, which expands the range of potential employment platforms.
And while current developments can lead to a set of battlefield weapons that increase U.S. combat power, they are not yet game-changers. Ultimately, DE weapons have to become credible near-term (less than five years) to midterm (less than 10) as offset candidates, those technologies that enable U.S. forces to maintain battlefield superiority against any adversary for use on appropriate operational platforms.
The development of substantially more capable DE weapon systems will require that DOD actively shape next-generation capabilities. The report give recommendations for how DOD should proceed in this area, mindful of past failed promises, but driven by the inherent warfighting potential that directed-energy weapons hold.
The report recommends “Develop, and communicate, a DOD-wide strategic plan, to develop and field suitable DE weapon systems for the department’s highest priorities”, “Establishing a joint directed-energy weapon program office to help drive mission focused programmatic outcomes in a context of time and budget constraints,” “Increase spending by two to three times for HEL and by five to 10 times for HPM roughly half what DOD spent at the end of the Cold War.”
DOD should push the most promising developments forward, ultimately considering limited-quantity procurements of those systems that address priority theater warfighting capability gaps. DOD should allocate a greater share of available resources to develop and field effective high-end DE capabilities , required to counter higher-end threats like high-speed ballistic or cruise missiles.
Potential U.S. adversaries benefit from the same underlying technology trends and, in some cases, aggressively seek to counter U.S. military superiority. DOD should increase its coverage of relevant foreign scientific and technical developments, both for early warning and to identify technology breakthroughs and potential opportunities. It should also conduct a net assessment of foreign developments on the U.S. defense posture.
Directed-energy weapons are not silver bullets, but rather one of a broader set of tools in the warfighter’s toolbox. Taken together, the parallel advances in directed energy, cybersecurity and electronic warfare could — if operated as a cohesive system — provide the nation an important, if dynamic, qualitative military edge.
An enhanced focus on combined directed energy/electronic warfare/cyber experimentation and wargaming would help DOD appropriately adjust its warfighting concepts, doctrinal approaches, technology development strategies and operational planning.
DOD should plan for future DE weapon successes, more capable next-generation DE weapons that may carry game-changing effects. The continuing development and eventual deployment of more capable DE weapons may diminish operational risk, create improved warfighting options and ultimately enable new operational courses of action. Properly executed, leadership and forces will be prepared as new capabilities —effectively shaped by DOD — become available.