Persistence is a key characteristic of unmanned aircraft. It is also a useful attribute for the aerospace industry, as it can take a long time for an idea to catch on. Take the concept of long-flying unmanned aircraft in the stratosphere acting as “atmospheric satellites” providing communications in rural areas or disaster zones. Fifteen years after it first tried to establish solar-powered UAVs as high-flying cell towers, AeroVironment has formed a joint venture with Japanese ...
