Tanker Charging Drone with Laser Focus of New DARPA Program

DARPA recently published a Request for Information (RFI) seeking feedback from the industry on a proposal to equip the Air Force’s existing KC-135 and KC-46 Pegasus tankers with an “underwing power beam pod.” Options too.

Such pods should contain a continuous wave laser that produces at least 100 kW and require a thermal control unit that integrates the laser into the tanker. The solution is also expected to provide beamforming and steering with laser energy that “covers a nearly hemispherical field of view” to ensure that power is reached where it is needed.

You also need to know more about how to get on the tanker and generate electricity first, using existing or new equipment.

In a broader sense, RFI wants to know from the enterprise whether it can not only adapt existing hardware, but also build and test the components and subsystems needed for Airborne Energy Well. The deadline for submission is July 11th.

As the main driving force behind the Airborne Energy Well initiative, the RFI outlines the need for UAVs to fly longer and recreates the benefits that traditional tanker aircraft offer to manned fleets. Second, drones will be able to reduce their organic energy storage, for example, to carry more weapons and sensors. Alternatively, you can benefit from long-term durability without landing. All-electric drones lined up to benefit from airborne energy wells now tend to be relatively small in size. However, larger UAVs are becoming more and more agenda, and having the ability to replenish battery cells while in the air may help address durability issues associated with electric drones.

In the short term, Airborne Energy Well may not need to recharge large aircraft, but over time, larger and more complex types (both manned and unmanned) will be battery-powered. It is set. Meanwhile, both DARPA and the Air Force are increasingly interested in the possibilities of electric vertical takeoff and landing (eVTOL) designs. It continues to evolve and grow in size as batteries become smaller and more efficient.

NASA’s X-57 project is the aviation’s first all-electric experimental aircraft, aimed at demonstrating the benefits of electric propulsion for aviation.

Of course, the airborne energy well also needs a compatible drone with some means of receiving the directed energy generated by the tanker. There are other potentially significant hurdles, such as atmospheric interference from clouds and the effects of precipitation on laser beam output.

With all of this in mind, a very tall and slow-flying aircraft that runs on electricity, flies for a very long time, stands in place of a communications satellite, or lifts a sensor high, is the best of this concept. It could be a “customer”. It also means that power is beamed up through a thin atmosphere with less weather than down, significantly reducing the major technical hurdles of such a concept.

Still, there are major challenges beyond beam propagation and atmospheric strain. This includes major thermal issues and both sender and receiver size and weight issues, to name just a few. These are not unique to this concept alone. With this past feature of us, you can read all about the reality and myths surrounding today’s directed energy weapon applications.

But in the end, DARPA suggests that if the provider and receiver subsystems can be completed, Airborne Energy Well could become part of a much larger and more ambitious energy transfer network. doing.

“This response to the RFI will be used to inform and investigate future programs that will improve the ability of aerial assets to dynamically move energy across a network of aircraft equipped with energy beam and reception techniques. “Masu,” said RFI. “This aerial energy well is a potential component of the broader energy web of power generation, transfer relays, and receiving solutions, allowing the Pentagon to dynamically allocate energy resources and provide military effects more flexibly. I will. “

The RFI specifies the potential incorporation of tankers in service, but there is no reason why the same technology could not be inserted into other manned and unmanned platforms in the future. Indeed, drones are now ready to begin flying traditional refueling missions, and even larger ones may be able to recharge battery-powered counterparts. Certain future manned aircraft may also be offered in unmanned or optionally pilot versions, which may help to become “charging stations” for other UAVs.

In addition, such techniques could begin to provide additional energy to aircraft equipped with systems that consume huge amounts of power, such as lasers. Thus, aerial energy wells, or the like, can have uses other than recharging for the propulsion of electric aircraft.

DARPA states that while for-profit companies began adopting wireless energy transmission some time ago, military adoption is generally lagging behind in certain applications.

Nevertheless, the Pentagon has been exploring the potential of this type of technology for at least some time.

In 2011, the Air Force Research Laboratory’s Revolutionary Munitions Department funded NASA’s research on laser-powered beam systems. As a precursor to airborne energy wells, this study focused on “long-range optical” refueling “of electrical platforms such as micro unmanned aerial vehicles (MUAVs).”

Another relevant precursor to the latest DARPA research can be found in 2014 when the NRL published a paper outlining the potential of pulsed power in plasma physics and military applications. In that paper, Thomas Merhorn, director of the NRL’s Plasma Physics Division, wrote:

“Rather than using a laser beam to kill a UAV, based on the concept of scalability, they began pursuing the idea of ​​beaming power into a UAV to enable continuous flight and could be applied to both surveillances. There is a possibility [Intelligence, Surveillance, and Reconnaissance (ISR)] And countermeasure missions. The team has a long-range laser output beam to the UAV offboard decoy, continuous monitoring, and communication relay. “

Two years later, the Navy issued a patent for a system that transmits power to a durable unmanned aerial vehicle. This system was pioneered by Dr. Paul Jaffe, an electronic engineer at the National Rugby League Research Institute (NRL).

Then, in 2019, the NRL conducted a three-day demonstration of the Navy’s latest power beam capabilities at the time. “If you have an electric drone that can fly for more than an hour, you’re doing pretty well,” Jaffe said at the time. “If there is a way to keep these drones and UAVs flying indefinitely, it will have a very wide range of effects. Power beaming has a way to do that.”

3-day Power Beam Demonstration at David Taylor Model Basin at Naval Battle Center in Bethesda, Maryland, 2019:

However, it’s worth noting that the NRL’s 2019 test used a 2 kW laser that transmitted energy over a distance of about 300 meters. DARPA is currently looking at a system with 50x power and a much longer transmission distance while both objects are in motion.

DARPA has previously worked on this topic as part of it. Following the agency-sponsored roundtable conference of powered aircraft in 2015, the Silent Falcon, a laser-powered aircraft, was demonstrated in 2018. It was intended to “demonstrate that remote electrical refueling of DoD systems with high energy laser power beams would extend mission operating time in competing remote environments.”

Currently, DARPA states, “Multiple technologies related to wireless energy transmission are being researched and developed to keep unmanned aerial vehicle systems operational.”

Using existing tanker aircraft as a platform for tanker aircraft is logical in the sense that they already help primarily increase the durability of manned aircraft. However, this role may be added to the tanker fleet’s already expanding mission roster, including its ability to act as a communications node for other platforms. This is also a time of increasing concern about the viability of tankers near the airspace being contested.

In addition to the Roll-On Beyond Line-of-Sight Enhancement (ROBE), which is part of the KC-135 fleet, there are plans for tankers to provide combat management capabilities for armed drones. Cockpit (RTIC) Initiative, War zone I have investigated it in the past. The tanker fleet is already struggling to meet the requirements, especially as the KC-135 and KC-10 are retired, so it is possible to relieve these pressures by increasing the burden on these valuable assets. you can’t.

But beyond this, it is clear that remote power generation has significant potential impact, especially in the field of long-lasting unmanned aerial vehicles and space. In fact, the secret X-37B spaceplane has also been involved in power beam testing, showing how interest in this technology is growing. In the future, satellite constellations could also power the drone. You can read an exclusive interview with the Chief Scientist of the X-37B Power Beaming Program here.

In addition to these aerial and space-based capabilities, this same type of technology will ultimately be used to allow remote military bases on land to receive energy and to power autonomous vessels at sea. It may change the way it is done.

With that in mind, Airborne Energy Well could just be the beginning of something much broader and truly revolutionary, perhaps unleashing the dream of essentially unlimited durability of flying vehicles. You can even pave the way. Still, it may be a dream, but there are absolutely big technical hurdles that must be overcome even to make this work at the most basic level, but this is to explore the concept and its feasibility. All about the DARPA program.

Contact the author: thomas@thedrive.com