Wind and Mountain Wave Observations From a Flight Test of a Solar-Powered Airplane

In support of NASA’s Environmental Research Aircraft and Sensor Technology (ERAST) program, flight tests of the Pathfinder solar-electric-powered, remotely piloted aircraft (RPA) were conducted at the Navy’s Pacific Missile Range Facility (PMRF), Barking Sands, Kaua’i, Hawaii, from May to November 1997 and from June to August 1998. This airplane was designed to operate at low speeds and low Reynolds numbers for long duration at altitudes above 60,000 ft (18 km). Three successive altitude world records for propeller-driven aircraft were established during these tests: 67,400 ft (20.54 km) on June 9, 1997; 71,350 ft (21.75 km) on July 7, 1997; and 80,201 ft (24.445 km) on August 6, 1998.