NASA Pathfinder Plus- Solar Powered Flight
NASA’s Pathfinder, designed by the same company that created the Gossamer Albatross, Penguin and Challenger, as well as the Helios. It was originally built in the early 1980’s but sat in storage before a series of test flights in 1993 and 1994. The Pathfinder set a new altitude record for solar aviation in 1995, reaching over 50,000 feet.
In 1998, longer wings were added to the unmanned solar plane and the aircraft was renamed the Pathfinder Plus. Pathfinder Plus beat previous altitude records when it reached nearly 97,000 feet in 2001.
NASA Pathfinder and Pathfinder Plus
Pathfinder
The NASA Pathfinder aircraft, designed and built by AeroVironment Inc., for the NASA Environmental Research Aircraft and Sensor Technology (ERAST) Program, is a lightweight, remotely-piloted, solar-powered aircraft weighing less than 600 lb. Pathfinder is a proof-of-concept forerunner for the Centurion and its successor, the Helios Prototype aircraft.
Pathfinder is constructed of state-of-the-art composites, plastics, and foam. The upper surface of the aircraft's 100-ft wing is covered almost completely by thin solar-cell arrays that collect sunlight and convert it into electricity. This electricity powers six small motors with propellers. Slowing down or speeding up these individual propellers allows Pathfinder to make turns, since it does not have ailerons and rudders typical of most airplanes.
Pathfinder Flight History
Pathfinder was developed in the early 1980s, and was adopted into NASA's ERAST Program in 1993. After initial flight tests at NASA Dryden Flight Research Center, at Edwards, CA, it was modified with additional solar arrays and other upgrades. Another series of development flights began in 1995. On September 11, 1995, Pathfinder reached an altitude of 50,500 ft, setting a new altitude record for solar-powered aircraft.
After more upgrades and one checkout flight at Dryden in late 1996, Pathfinder was deployed to the U.S. Navy's Pacific Missile Range Facility (PMRF) at Barking Sands, Kauai, HI, in April 1997 . Kauai was chosen as an optimum location for testing the solar-powered Pathfinder due to its high levels of sunlight, available airspace and radio frequencies, and the diversity of terrestrial and coastal ecosystems for validating scientific imaging applications. While in Hawaii, Pathfinder flew seven high-altitude missions from PMRF. By this time it was clearly the world's highest-flying solar-powered aircraft. With a flight to 71,530 ft Pathfinder had also flown higher than any other propeller-driven aircraft.
Pathfinder Plus 
Essentially a transitional vehicle, the Pathfinder Plus was a hybrid of the technology employed on Pathfinder and developed for the Centurion/Helios Prototype.
During 1998, the Pathfinder was modified into the longer-winged Pathfinder Plus configuration. On August 6,1998, the Pathfinder Plus was flown to an altitude of approximately 80,200 ft, again setting new standards for solar-powered and propeller-driven aircraft. The goal of the flights was to validate new solar, aerodynamic, propulsion, and systems technologies developed for the Pathfinder's successor, the Centurion/Helios Prototype.
The most noticeable change in the Pathfinder Plus was the installation of a center wing section that incorporated a high altitude airfoil designed for Centurion. The new section was twice as long as the original Pathfinder center section and increased the overall wingspan of the craft from 98.5 to 121 ft. The new center section was topped by more efficient silicon solar cells that could convert 19 percent of the solar energy they receive into useful electrical energy to power the craft's motors, avionics, and communication systems. Maximum potential power was boosted from about 8,000 kW on Pathfinder to about 12,500 kW on Pathfinder Plus. Pathfinder's six motors were replaced by motors designed for the Centurion, and two additional motors were mounted on the center section of the wing.
NASA Pathfinder aircraft taking off September 11, 1995 when it set the new solar powered altitude record
Specifications for NASA's Pathfinder Plus
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Length: 12 ft |