Solar Powered UAV Technology for US Military

Solar-powered Unmanned Aerial Vehicles (UAVs) for the US military could become a reality, once solar panel technology for conventional aircraft designs can be made more energy efficient.  US researchers led by scientists from Washington University are presently developing flexible, lightweight solar cells to be fitted to aircraft wings.  These types of cells are designed to drive sensors/actuators located internally, meaning that electric wires are not needed and, therefore, the UAVs’ weight can be kept to a minimum.

“These kinds of solar cells have more specific power convergence efficiency, very clean energy and easy scalability to a larger skin area of the craft, as well as low-temperature processing, which leads to lower costs overall”, head researcher Minoru Taya explained.

UAV Solar Cells

The UAV solar cells being developed are not like other types of solar cells, since they are what is known as ‘dye-sensitized’.  According to Taya, the researchers looked to the natural world for inspiration during the technology’s conception stage.  The solar cell design, he said, took its lead from photosynthesis carried out by natural dyes, an act “inherent in biological species, leaves, bacteria.”

“Thus, the cost of processing is much cheaper than that of the current silicon-based solar cells, which require high temperature clean-room handling”, he explained.

Solar Powered Unmanned Aircraft

Progression to the current phase of solar powered unmanned aircraft development has proved complicated.  The researcher’s initial experimentation involved applying their solar cells to model aircraft.  While they found that the cells were an effective power source, they were also too weighty to permit the aircraft to get off the ground.  However, in later trials, they introduced film-battery technology, linked up to lithium batteries, as a means of capturing solar energy. 

“Any airborne energy harvester must satisfy additional requirements, like weight and durability in airborne environments”, Taya commented. “If those are met, then there may even be longer [UAV] flight times.”  The more time spent in the air by these solar powered UAVs, the less they would need to refuel, and this could be crucial in guaranteeing a successful mission.  By the same token, the DoD (US Department of Defence) would benefit from lower levels of energy consumption.

However, the UAV solar cell technology still needs to be refined before it can be deployed to the front line, including ensuring that it is durable, and that it can be slotted in alongside existing US Air Force technologies.

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