The Emerging Directed Energy Weapons

Minutes

On March 22nd, 2024, in the Powell Auditorium of the Cosmos Club in Washington, D.C., President Larry Millstein called the 2,492nd meeting of the Society to order at 8:08 p.m. ET. He began by welcoming attendees, thanking sponsors for their support and announcing new members. Scott Mathews then read the minutes of the previous meeting which included the lecture by Eric Cline, titled “Survival of Civilizations: After 1177 BCE”. The minutes were approved as read.

President Millstein then introduced the speakers for the evening, Thomas Karr, of MITRE Corporation, and James Trebes, of the Dept. of Defense (Ret.). Their lecture was titled “The Emerging Directed Energy Weapons: Are they finally ready to provide real military capability?”.

The two speakers alternated throughout the lecture. Karr began by indicating that the lecture would focus on laser-based weapons, with some discussion of microwave weapons, and no discussion of particle beam weapons. Karr presented an outline of the lecture, including: some history, physics, lethality, current US systems, foreign systems, and military challenges.

Trebes then discussed the physics of directed energy weapons (or DEWs), describing the variety of ways the energy beam could damage or interfere with a target, including: heating, creating fractures, spallation, shock waves, disruption in air flow, RF effects, and high electric fields. He described the potential advantages of DEWs in terms of low cost per shot and “deep magazines”. He discussed his view of the roadmap for DEWs, starting with simple, short-range systems capable of destroying UAV’s, drones, and artillery, to mid-range systems, capable of destroying cruise missiles, to complex, long-range systems capable of defeating hypersonic and ballistic missiles.

Karr then described some of the physics of DEWs. Given the focus on laser weapons, he presented graphs of the atmospheric transmission windows, indicating which lasers operated in each of the windows. He discussed the early work in the field using chemical lasers, then the semiconductor and solid-state lasers which began to appear in the 1970’s and 80’s, and the subsequent development of high-power fiber lasers, which now represent the state-of-the-art. He showed examples of diode-pumped, fiber lasers that are currently capable of generating and delivering hundreds of kilowatts of average power. He then mentioned the 22 specific DEWs systems deployed by the US for defense against “soft targets”. Karr briefly discussed the physics of combining fiber lasers, to create a more powerful beam, stating that these techniques will likely be used to create future weapons to defeat “hard targets”. He then presented some of the additional systems that need to be integrated with the laser source to create an effective weapon. These included: the power source, cooling system, beam director, target tracking, fire control, and command & control systems.

Trebes then discussed some of the physical limitations of DEWs. For laser-based systems, these include: atmospheric turbulence, thermal blooming, and self-focusing. For high power microwave systems, the primary limitation is atmospheric electrical breakdown. He presented the concept of the “Kill Chain”, describing the flow of information from long-range radar, local radar, and target tracking to the command & control center, and then to the weapon’s fire control system. Trebes then discussed “kill assessment”, and various types of kills. These included “system kills”, which result in “flaming wreckage”, and “mission kills”, which prevent mission completion. He noted that most laser weapons result in mission kills, and not system kills. He then discussed the ways in which a HPM system can get electromagnetic energy through the cracks and seams in a weapon to disrupt its electronics.

Karr then showed images of deployed DEW systems in the US military, and gave more details about each. These included the Navy ODIN (optical dazzling interdictor), the Army DE-MSHORAD (maneuvering short range air defense), the Marine CLAWS (compact laser weapons system), and the Air Force HELWS (high energy laser weapon system). He then showed images and gave details about future systems currently under development by the US military. He also showed examples of DEW systems being deployed or developed by other countries.

Both speakers then presented some of the difficulties in having the US military adopt DEWs. They discussed the fact that the Pentagon, and the warfighter in particular, do not trust these weapons systems because they are largely untested on the battlefield. They mentioned the bureaucratic hurdles associated with the “Integrated Defense Acquisition, Technology, and Logistics Life Cycle Management System”. They discussed the fact that the military has many different weapons systems that compete with DEWs. And finally, they discussed the fact that while the cost-per-shot was very low…on the second shot…these systems require considerable capital investment.

The lecture was followed by a short, collegial debate. Karr argued that each branch of the military should create a new office to direct research into DEWs. He argued that this research should be moved from the traditional research labs (ARL, NRL, AFRL) to new labs that specialize in building weapons. Trebes argued that the creation of new agencies or offices were not necessary. He argued that such “specialty organizations” would only work if the organizations were given some form of congressional mandate, forcing them to spend money on DEWs research. In the end, the two speakers agreed that they were “not that far apart”.

The lecture was followed by a Question and Answer session, however, in the interest of time, the details of the Q&A session have been omitted from the minutes.

After the question and answer period, President Millstein thanked the speakers and presented them with PSW rosettes, signed copies of the announcement of their talk, and signed copies of Volume 1 of the PSW Bulletin. He then announced speakers of up-coming lectures, made a number of housekeeping announcements, and invited guests to join the Society. He adjourned the 2492nd meeting of the society at 10:29 pm ET.

Temperature in Washington, DC: 9.4° Celsius
Weather: Cloudy
Audience in the Powell auditorium: 52
Viewers on live stream: 53 …for a total of 105 live viewers
Views of the video in the first two weeks: 946

Respectfully submitted, Scott Mathews: Recording Secretary