As part of the ERAST program, AeroVironment built four generations of long endurance unmanned aerial vehicles (UAVs) under the leadership of Ray Morgan, the first of which was the Pathfinder.

In 1983, AeroVironment obtained funding from an unspecified US government agency to secretly investigate a UAV concept designated "High Altitude Solar" or HALSOL.

[2] In 1993, after ten years in storage, the aircraft was brought back to flight status for a brief mission by the Ballistic Missile Defense Organization (BMDO).

By the time the aircraft was adopted into the ERAST project in late 1993, solar cells were being added, eventually covering the entire upper surface of the wing.

During those flights, Pathfinder carried two lightweight imaging instruments to learn more about the island's terrestrial and coastal ecosystems, demonstrating the potential of such aircraft as platforms for scientific research.

That compared with about 14 percent efficiency for the older solar arrays that cover most of the surface of the mid- and outer wing panels from the original Pathfinder.

[3] The Pathfinder-Plus development flights flown at PMRF in the summer of 1998 validated power, aerodynamic, and systems technologies for its successor, the Centurion.

On August 6, 1998, Pathfinder-Plus, piloted by Derek Lisoski, proved its design by raising the national altitude record to 80,201 feet (24,445 m) for solar-powered and propeller-driven aircraft.

[1][5] In July 2002 Pathfinder-Plus carried commercial communications relay equipment developed by Skytower, Inc., a subsidiary of AeroVironment, in a test of using the aircraft as a broadcast platform.

"A single SkyTower platform can provide over 1,000 times the fixed broadband local access capacity of a geostationary satellite using the same frequency band, on a bytes per second per square mile basis.