- News
25 April 2019
Alta Devices launches Anylight Solar for HALE product for high-altitude long-endurance UAVs
Alta Devices of Sunnyvale, CA, USA (a subsidiary of Hanergy Thin Film Power Group Ltd of Beijing, China) has announced a new solar solution designed to meet the specific needs of unmanned aerial vehicles (UAVs) that can serve as platforms for cellular and Internet of Things (IoT) connectivity. Combining the firm’s solar cell technology with several new inventions yields features that can maximize power, minimize weight and provide sufficient protection from the harsh environment commonly found in the Earth’s stratosphere (at 60,000ft).
High-altitude long-endurance (HALE) UAVs that fly at stratospheric levels - or high-altitude pseudo satellites (HAPS) - comprise an important new aircraft category and can include airplanes, airships, and/or balloons that can fly at altitudes of 20km (60,000ft) for extended periods of time. In addition to being used for communications (such as cell phone connectivity etc), these aircraft can be used for intelligence surveillance & reconnaissance (ISR), search & rescue, border patrol, mapping and many other applications. Solar power is critical for these aircraft, particularly because the objective is to fly for years without refueling.
Flight at this altitude demands solar technology that is different from the type used in terrestrial installations or in space. For example, at 60,000ft, ultraviolet radiation from the sun is more intense than on the earth’s surface. Unlike in space with zero gravity, the generation of lift is important for stratospheric vehicles. To allow the aircraft to carry a useful payload and enough batteries for night flight, the solar technology used must be extremely light-weight. In contrast to both terrestrial and space applications, at 60,000ft mechanical stresses during flight can be very tough on the aircraft surface and solar panels, so the solar material must be flexible and durable.
Alta Devices’ new ‘Anylight Solar for HALE’ product (available now) uses its record-efficiency (29.1%) single-junction gallium arsenide (GaAs) solar cells (unveiled in December), producing what is claimed to be industry-leading power per unit area of over 300W/m2 under high-altitude operating conditions. Alta says it has worked with its HALE aerospace customers to solve critical challenges related to the mechanical and electrical integration of the technology onto multiple aircraft platforms. The firm developed special, lightweight packaging that protects the solar cells from the extreme UV, ozone and thermal environment of the stratosphere while maintaining a smooth, aerodynamic surface.
Other crucial challenges addressed by Alta include designing for mechanical stresses and vibration expected during flight and developing techniques for co-curing into lightweight composite structures. Optimizing a solar array for an aircraft requires complex configurations that maximize cell-packing factor (providing industry-leading packing density of up to 94% including diodes and connectors), minimize electrical mismatch and allow the design to utilize the maximum surface area for solar. Alta says that it worked with its customers to understand these requirements and developed module designs that address these issues, providing an easy-to-integrate solution that maximizes system performance while reducing the work required during installation.
“Our aerospace customers need to innovate every aspect of these new and complex aircraft systems,” says CEO Jian Ding. “With our new HALE solar solution, they now have one less thing to worry about,” he adds. “This will simplify the design process and significantly reduce the complexity involved in manufacturing these aircraft.”
Alta Devices says that engineers with extensive expertise in integration are available for customer support and advice on optimal integration techniques such as co-curing or adhesives. Finally, it is ramping its production capability in response to its customers, who plan to manufacture a multitude of HALE aircraft in the near future, the firm adds.
Alta sets seventh consecutive single-junction solar cell efficiency record, at 29.1%