U.S. Air Force Airborne High-Power Laser System Sees Key Progress

Recently, the U.S. Air Force Research Laboratory (AFRL) successfully completed flight testing of a new beam guide concept. This concept can be used with a directed energy laser system integrated into an aircraft.
The team, comprised of personnel from AFRL's Aerospace Systems Directorate, Directed Energy Directorate at Cortland Air Force Base, New Mexico, and prime contractor MZA Associates, reportedly developed and tested a low-power, subscale beam guide to evaluate the capabilities of various aerodynamic flow control techniques to mitigate the optical and mechanical distortions associated with laser beams on high-speed flying airborne platforms. optical and mechanical distortions associated with the laser beam on a high-speed flight airborne platform.
The HARDROC beam director is a technological leap forward in minimizing aerodynamic degradation," said Rudy Johnson, HARDROC program manager. "This series of flight tests has demonstrated the effectiveness of flow control in reducing the aerodynamic impact of the beam director."
Researchers at the U.S. Air Force Research Laboratory (AFRL ) have been developing the flow control system at the heart of HARDROC for several years. According to Dr. Scott Sherer, CFD lead for the HARDROC project, "Using advanced computational fluid dynamics (CFD) simulation techniques, we were able to significantly reduce air effects at very high speeds and over a very large angular range. We effectively leveraged the significant computational time provided by the DoD High Performance Computing Modernization Office to determine which flow control techniques would work, which were worth pursuing, and which were not."
Working closely with their counterparts in the Directed Energy Directorate, the Aerospace Systems Directorate team drew on previous efforts in beam guide development to further advance the technologies used in the HARDROC project.
"Advancing flight testing is a tremendous task and accomplishment for the HARDROC team," said Dr. Matthew Kemnetz, co-principal investigator for air effects and beam control at the AFRL Directed Energy Council at Cortland Air Force Base, N.M. "These data from the flight tests will help the development of the airborne beam indicator move forward."
While advanced flow control techniques are at the heart of the HARDROC project, modifying these aerodynamics and combining them with realistic optics is critical to demonstrating the effectiveness of the overall system.
"Based on the results of our computational simulations and wind tunnel experiments, we are very confident that the airflow control system will perform well. But the big question in our minds was whether these flow control techniques could be used with the sensitive optics required for advanced directed energy systems. And HARDROC quickly solved that problem."
To get those answers, AFRL contracted with MZA, a world leader in modeling, analysis, design, development, integration and testing of high-energy lasers (HELs) and advanced optical systems, to design a sub-scale system that could be used in a wind tunnel or an aircraft.
The final design was ground tested in an environmental chamber and wind tunnel to ensure functionality and performance under load, followed by final flight testing on a business jet in the summer and fall of 2022. During the flight tests, the aircraft cruised at high speed while various sensors were used to measure aerodynamic disturbances. The data show that the HARDROC beam guide extends the operational range of the airborne directed energy system, providing a 360-degree field of view over a wider speed range at a much smaller size, weight and power (SWaP).
The successful flight demonstration of the HARDROC turret clears a major technical hurdle for operating high-power lasers on high-speed aircraft in a variety of Air Force missions," said Dr. Mike Stanek, technical advisor for the Aerospace Systems Council's Integrated Systems Division. The integration of a smaller size, weight and power HARDROC turret than other types of integration strategies allows for less laser power to be lost to air effects, resulting in improved mission performance."