Solar-powered airplanes could fly for months, but they need just one thing

Researchers from Harvard and Michigan universities are exploring solar-powered drones that could fly for weeks or months. The key is achieving an energy density of 500 Wh/kg, allowing these drones to operate in the stratosphere. Solar panels would charge batteries during the day, enabling nighttime flight. The Sceye company has developed a solar airship for stratospheric communication. Current battery technology is approaching 400 Wh/kg, but costs remain high. The goal is to reduce operational costs and extend observation periods for climate research and disaster monitoring.