Mar 20, 2017

Graham Warwick | Aviation Week & Space Technology

Lockheed Claims Fiber-Laser Power Record

Lockheed Martin is eyeing new U.S. Army, Navy and Air Force opportunities for high-power laser systems after demonstrating a 60-kW-class system for delivery to the Army in the next few months.

In tests this month, the laser produced a single beam of 58 kW and is expected to reach the 60-kW goal after further optimization before delivery to the Army, says Rob Afzal, senior fellow for laser and sensor systems with Lockheed Martin’s Cyber, Ships & Advanced Technologies unit.

The electric laser achieves high power with “near-perfect” beam quality by spectrally combining the outputs from multiple kilowatt-class fiber lasers into a single beam. “We are not aware of a higher-power beam-combined laser of this type,” Afzal says.

The Army will mount the system in its High-Energy Laser Mobile Test Truck (Helmtt), which currently carries a 10-kW laser. The laser has demonstrated an electric-to-optical efficiency of more than 43%, which Afzal says allows the power and cooling systems to be small enough to fit in a truck.

Lockheed says its 60-kW laser is compact enough to fit the Army’s FMTV truck. Credit: Lockheed Martin

Having previously developed the 30-kW Athena in 2015 using the same laser technology, Lockheed has verified its approach is scalable up as well as down in size. “We have shown that beam-combined lasers are real and scalable, with a path to higher powers as the services need them,” he says.

Efficiency is key, Afzal notes, because a mobile high-energy laser is expected to be powered by batteries that would be recharged between shots by an engine-driven generator. Similarly, the waste heat generated would be stored during firing and dumped between shots.

For the next steps, the Army, Navy, Air Force and Special Operations Command (SOCOM) all have upcoming opportunities for high-energy lasers, he says. The Air Force Research Laboratory plans to demonstrate a podded laser for self-protection of fighters under the Shield program.

The Navy plans to field a 60-kW-class laser operationally on a destroyer in the fiscal 2020 time frame under the Seasaber Increment 1 Laser Weapon System program and to test a 150-kW laser at sea within a year.

With Lockheed’s 60-kW laser producing 50 kW when installed, the Army’s Helmtt will conduct lethality demonstrations against rocket, artillery and mortar (RAM) and unmanned aircraft system (UAS) threats in fiscal 2018.

As a follow-on, the Army plans the HEL TVD (for Tactical Vehicle Demonstrator), which will conduct a counter-RAM and UAS demonstration in fiscal 2022 to support potential transition to the Indirect Fire Protection Capability, Increment 2-Intercept program.

SOCOM, meanwhile, is seeking funding to modify an AC-130W gunship with a high-energy laser as early as fiscal 2020 to provide an offensive capability

Cleaner-Burning Biofuels Reduce Contrails

Contrails from cruising aircraft are estimated to have a greater impact on the Earth’s atmosphere than all aviation-related carbon dioxide emissions since the first powered flight. Biofuel blends can reduce the particle emissions that form contrails by 50-70%, according to the results of NASA-led research flights.

Data on particulate emission in cruise flight were collected in 2013-14 during flights of NASA’s Douglas DC-8 in which German aerospace center DLR and Canada’s National Research Council (NRC) participated. The CFM56-powered DC-8 was flown on conventional Jet A1 fuel and a 50:50 mix of biofuel and Jet A1.

The DC-8 was flown at commercial-aircraft cruise altitudes while NASA’s Dassault HU-25 Guardian, DLR’s Dassault Falcon 20 and NRC’s Lockheed CT-133 took turns flying behind the four-engine aircraft at distances of 100-500 ft. to sample the exhaust plumes at different thrust levels.

NASA’s ACCESS 2 flights directly measured biofuel particulate emissions in flight. Credit: NASA

Jet engines emit soot particles that, if the air is humid and cold enough, serve as nuclei for the condensation of water droplets and ice crystals that form contrails. The ice crystals can form persistent and sometimes extensive high-altitude clouds known as contrail cirrus. By reflecting sunlight back into space and trapping heat radiated by the Earth, these clouds can affect the climate.

“This was the first time we qualified the amount of soot particles emitted by jet engines while burning a 50:50 blend of biofuel in flight,” says NASA’s Rich Moore, lead author of a paper reporting the results published in Nature.

“The soot emissions largely determine the number of ice crystals in contrails,” says DLR’s Hans Schlager, co-author of the paper. “The possibility of reducing the engine exhaust soot emissions by more than half using biofuels paves the way for reducing the climatic impact of contrails.”

The DC-8 tests, under NASA’s Access 2 (for Alternative Fuel Effects on Contrails and Cruise Emissions) study, were conducted using conventional Jet A1 fuels with moderate and low sulfur levels and a blend with HEFA (hyprocessed esters and fatty acids) biofuel produced from camelina.

DARPA’s Gremlins Advance Toward Flight

Low-cost unmanned aircraft systems (UAS) that can be launched in volleys to cooperate with each other and with manned aircraft, then be retrieved in mid-air and reused, are a step closer to reality.

DARPA has awarded contracts for Phase 2 of its Gremlins program to Dynetics and General Atomics Aeronautical Systems. They were selected over the other Phase 1 participants, Lockheed Martin and Kratos.

“The Phase 1 program showed the feasibility of airborne UAS launch and recovery systems that would require minimal modification to the host aircraft,” says Scott Wierzbanowski, DARPA program manager.

Gremlins focuses on the challenge of recovering unmanned aircraft to a C-130 in flight. Credit: Dynetics

Under Phase 2, the two teams in 2018 will complete preliminary design of full-scale “aircraft carrier in the sky” technology demonstrators and perform risk-reduction tests on individual system components.

DARPA plans to select one team to develop the technology demonstration system and conduct flight tests, scheduled for 2019, involving the airborne launch and recovery of multiple Gremlins.

Kratos, which participated in Phase 1 as both a prime and a subcontractor to system integrator Dynetics, continues into Phase 2. Its Composites Engineering Inc. (CEI) subsidiary will support Dynetics by developing and building prototype jet-powered UAS.

Purpose-designed air-recoverable and -reusable limited-life UAS will be jet-powered. Credit: General Atomics Aeronautical Systems

In the Gremlin concept, groups of UAS would be launched out of range of adversary defenses from platforms ranging from fighters to transports and including other unmanned aircraft.

The volleys of low-cost UAS, carrying various payloads, would perform surveillance, jamming or strike missions to augment manned aircraft. After a mission, the UAS would be retrieved in flight by a C-130 transport, returned to base and prepared for reuse within 24 hr.

The Gremlin’s expected lifetime is about 20 missions, says DARPA. Making the vehicles recoverable and reusable, versus expendable, could provide significant financial savings by reducing airframe and payload costs as well as mission and maintenance costs, the agency believes.

Japan Embraces UAS Airspace Management

Japanese online retailer Rakuten has formed a joint venture with low-altitude airspace service provider AirMap to provide air traffic management for unmanned aircraft systems, or UTM, in Japan.

Rakuten is developing a drone delivery service, called Sora Raku, and participated in AirMap’s Series B investment round in February, along with Airbus, Microsoft, Qualcomm and others.

The online retailer has been testing drone delivery since April 2016, beginning with a one-month pilot delivering golf balls to players on a course near Tokyo. In October, Sora Raku delivered groceries in Imabari, part of a project aimed at delivering fresh produce to the isolated residents of the Shimanami islands on the Seto Inland Sea that separates three of Japan’s four main islands.

Rakuten’s Sora Raku drone delivery testing involves the Tenku hexacopter small UAS. Credit: Rakuten

In November, Rakuten’s Tenku hexacopter conducted the first test of drone delivery remotely operated using an LTE wireless network. The flight was conducted with telecom provider NTT Docomo and Autonomous Control Systems Ltd. (ACSL), a spinoff from Chiba University and the drone’s developer.

The flight, conducted in Chiba, used an improved Tenku designed for flight over water and urban areas, with longer range and a recovery parachute to slow the drone’s descent in the event of an emergency. Rakuten is an investor in ACSL.

In January, ACSL conducted a 12-km (7.5-mi.) delivery flight using the PF1 aircraft that is the basis of Rakuten’s Tenku drone. The 15-min. test flight was conducted in the Fukushima Hama-Dori Robot Testing Zone. Flights up to 20 km, and with multiple drones simultaneously, are planned for the summer.

One of Rakuten’s goals for its Sora Raku service is to deliver goods from the company’s fulfillment center in Ichikawa to Makuhari New City in Chiba, a distance of 10 km, by 2020.

The new Rakuten AirMap joint venture will provide UTM services to drone operators and airspace managers in Japan. Operators will be able to create flight plans and file them with airport and airspace managers. Airspace mangers will be able to view drone flight notices, automate authorization and communicate directly with operators, says AirMap.

Mesmer Detects, Identifies and Seduces Drones

Amid intensifying government and commercial interest worldwide in systems to counter the threat from drones, startup Department 13 has demonstrated its software-based Mesmer system in Australia and New Zealand.

Columbia, Maryland-based Department 13 has been approved by the U.S. to sell its initial Mesmer V1.0 product in all but five countries around the globe. CEO Jonathan Hunter says the Commerce Department has certified the system is not a jammer that would interfere with other aircraft.

Mesmer works by exploiting the communication protocols in the command-and-control links to drones. Initially, the system is approved for use only in detecting UAVs. Hunter says Department 13 is actively working to obtain clearance to use the system to mitigate the drone threat.

Mesmer exploits communications protocols to identify and take control of drones. Credit: Department 13

“We sense the radios of the drones or their operators,” he says. “There are certain unique things we look for. We get a 99.9% positive identification, with low false alarms.” To neutralize the UAV, Mesmer manipulates the protocols. “We get the drone to listen to us, then we mitigate,” he notes.

Hunter does not think the Federal Communications Commission will ever allow jamming by commercial operators of counterdrone systems. But to enable mitigation of the drone threat, the FAA will have to change regulations that prohibit any interference with aircraft.

This will require a change in regulatory language, he says, as the FAA currently defines all drones as aircraft. While it seems unlikely that the agency would budge on a definition it has defended aggressively, Hunter says the FAA is looking at the issue, which is also being debated by Congress.

“Government customers can use mitigation now. Commercial customers can use the system for detection and identification, but mitigation is restricted by law,” he says. “But large commercial entities are working to get the language changed so they can protect their facilities.”

Department 13 conducted demonstrations and operational evaluations in Australia for potential government, military and law-enforcement customers. “We believe a contract will follow,’ says Hunter. In the U.S., Booz Allen Hamilton has licensed Mesmer for potential demonstration for the military.

Mesmer software is designed to run on any hardware, and Department 13 plans to license the system as a software application to defense and commercial integrators of large-scale counter-UAV systems. “V1.0 is ready to ship. It is working on our rooftop, running 24/7,” he says.

The communications protocols Mesmer exploits are specific to drone types, “but 90% of the market uses the same 7-10 protocols, which makes it a little easier,” he says. Department 13 is working under Pentagon contract on extracting the information from “blind” or unknown signals using machine learning.*