 The NASA Pathfinder, Centurion, and Helios aircraft were a series of solar- and fuel cell system-powered UAVs, which AeroVironment, Inc. developed the vehicle under the ERAST program.Pathfinder, which was designed and built by AeroVironment, is essentially a flying wing with a 99-foot span.Solar photovoltaic cells mounted on the top of the wing produce up to 7,200 watts, powering the aircraft's six electric-driven propellers, as well as the suite of scientific instruments.