We first covered California-based Alta Devices' solar cells being used on UAVs in 2013, when they enabled a prototype solar-powered version of AeroVironment's small Puma AE to stay aloft for over nine hours. Now looking to give high altitude long endurance (HALE) UAVs the ability to stay in the air for much, much longer – even years at a time – the company has just released its Anylight Solar for HALE product.
Built around Alta Devices' single junction gallium-arsenide solar cells, which boast world-record efficiency of 29.1 percent, combined with specialized packaging to withstand the conditions found at altitudes of 20 km (60,000 ft) for extended periods, Anylight Solar for HALE is intended for airplanes, airships, and/or balloons flying at such altitudes.
The company says the specialized packaging it developed for the product is lightweight and boasts a smooth, aerodynamic surface, while providing protection from the extreme UV radiation, ozone and temperatures found at high altitudes. Weight is obviously an important factor for aircraft that need to stay aloft for extended periods, yet still be able to carry their payload and batteries to keep them operating through the night.
Working with potential customers, Alta Devices says the product has also been designed to mechanically and electrically integrate easily into various aircraft while providing maximum surface area for the flexible solar cells. The company claims power output of 300 W/m2 (28 W/ft2) for the Anylight Solar for HALE product in high altitude conditions.
HALE UAVs, which are also known as high altitude pseudo satellites (HAPS), have a range of potential applications, including as flying cell phone towers, for intelligence surveillance and reconnaissance (ISR), search and rescue, border patrol and mapping – all without the expense associated with launching satellites into orbit. We've seen a number of solar-powered HALE UAVs take to the air in recent years targeting such applications, and with the release of Anylight Solar for HALE that number only looks set to increase.
Source: Alta Devices
I wonder if you can use heat absorption during the day for a bunch of the required lift.