Pathfinder. Developing a solar rechargeable aircraft

Some assignments, both civilian and military, are better performed by unmanned, long-endurance, solar rechargeable aircraft high in the atmosphere than by satellites in low Earth orbits. These aircraft would have more flexible flight paths and would be far less costly than satellites to design, build, and operate. In collaboration with AeroVironment, Inc., the authors developed a lightweight flying wing, called Pathfinder, that uses present-day technologies in photovoltaics, power electronics, aerodynamics, and guidance and control. Because of its light weight, 30 m wingspan, and intended high peak altitude (2025 km), Pathfinder is span loaded; that is, the weight of all components is distributed as evenly as possible across the five modules that make up its wing. Flight tests have proven the soundness of the concepts and components.