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Pathfinder

The Pathfinder was designed and fabricated by AeroVironment in the early 1980's to support a classified program. After its initial flight series, it was determined that the technology required had not reached a level where ultra long duration flight (many days) under solar power could be achieved. At that point the aircraft was placed in storage.   Pathfinder Home Page

DFRC Photo # Photo Date Image Description
  Skip links in main table Pathfinder Photo Collection Contact Sheet
Pathfinder in Hawaii (DFRC Press Release 97-39)
EC97-44287-1 August 28, 1997 Pathfinder over runway in Hawaii
EC97-44287-2 August 28, 1997 Pathfinder in flight over Hawaii
EC97-44288-1 October 25, 1997 Pathfinder in flight over Hawaii
Record Setting Flight Over Hawaii - 71,490 feet
EC97-44138-1 July 7, 1997 Pathfinder aircraft liftoff on altitude record setting flight of 71,490 feet
EC97-44138-2 July 7, 1997 Pathfinder ground preparations prior to altitude record setting flight of 71,490 feet

EC96-43765-8 November 1996 Pathfinder aircraft being assembled - wing assembly
EC96-43817-2 November 1996 Pathfinder aircraft prepared for flight at dawn on lakebed
EC96-43817-4 November 1996 Pathfinder aircraft prepared for flight showing solar cell arrays on wing
EC96-43817-6 November 19, 1996 Pathfinder aircraft flight #1
EC96-43817-7 November 19, 1996 Pathfinder aircraft flight #1
EC96-43817-9 November 19, 1996 Pathfinder aircraft flight #1
EC96-43817-10 November 19, 1996 Pathfinder aircraft checkout flight #1
EC96-43817-11 November 19, 1996 Pathfinder aircraft flight #1
EC96-43817-12 November 19, 1996 Pathfinder aircraft flight #1
EC96-43817-13 November 19, 1996 Pathfinder aircraft flight #1
EC96-43817-14 November 19, 1996 Pathfinder aircraft flight #1
EC95-43261-1 September 11, 1995 Pathfinder aircraft taking off - setting new solar powered altitude record
EC95-43261-2 September 11, 1995 Pathfinder aircraft taking off - setting new solar powered altitude record
EC95-43207-76 July 27, 1995 Pathfinder aircraft in flight
EC95-43329-5 September 8, 1995 Pathfinder - first flight preparation on lakebed
EC95-43329-6 September 8, 1995 Pathfinder - first flight preparation on lakebed at sunrise
EC93-42240-37 October 20, 1993 Pathfinder - flight preparation on lakebed at sunrise
EC95-43207-6 July 27, 1995 Pathfinder - closeup of flight preparation on lakebed at sunrise
EC95-43207-8 July 27, 1995 Pathfinder - closeup of flight preparation on lakebed at sunrise
EC95-43378-19 January 9, 1996 Pathfinder on lakebed preparing for test flight
ES95-43373-6 December 10, 1995 Pathfinder on lakebed preparing for test flight
ES95-43373-17 December 10, 1995 Pathfinder on lakebed rolling out for test flight
ES95-43373-18 December 10, 1995 Pathfinder returning to hangar
ES95-43373-3 December 10, 1995 Pathfinder on lakebed after test flight
EC95-43373-20 December 10, 1995 Pathfinder on lakebed after test flight
EC93-42240-25 October 20, 1993 Pathfinder in flight over lakebed

Additional Information

The basic configuration and concepts for Pathfinder were first realized with the HALSOL (High Altitude Solar) aircraft, built in 1983 by AeroVironment and the Lawrence Livermore Laboratory. Pathfinder is constructed of advanced composites, plastics, and foam, and despite a wingspan of nearly 100 feet, it weighs only about 600 pounds. The wing is very flexible, which enables it to distribute the load almost entirely a long its span. It is propelled by 6 electric motors, each turning a composite propeller. Current from solar arrays provides power during daylight, while stored energy allows flight after dark. The batteries allow an endurance of about two hours in darkness.

On September 13, 1995 the aircraft achieved a major milestone in the ERAST program when it was flown to an altitude of 50,567 ft during a nearly 12-hour mission. The previous altitude record for a solar-powered aircraft was 14,000 feet. It now also holds an unofficial record of 67,350 feet, reached during the tests from the Navy's Pacific Missile Range Facility. Pathfinder resumed test flights from the U.S. Navy's facility on the Hawaiian island of Kauai in mid-1997. Kauai's lower latitude provides a better angle for Pathfinder's solar cells to absorb radiation from the sun, and its prevailing northerly winds allow Pathfinder to be oriented to the best sun angle for longer periods.

Pathfinder is one of several unpiloted prototypes under study by NASA's ERAST (Environmental Research Aircraft and Sensor Technology) program, a NASA-industry alliance which is helping develop advanced technologies that will enable aircraft to study the earth's environment during extremely long flights at altitudes in excess of 100,000 feet. Pathfinder flies very slow, within a narrow speed range. Takeoff is at about 17 mph, cruise speed is about 21 mph, and it climbs at 150 fpm. Pathfinder pilot Dave Ganzer says, "It's like flying underwater, because everything happens at such a slow time scale." Because of its slow speeds Pathfinder flights are meticulously planned around the weather. Winds during takeoff and landing need to be less than 12 mph. Mission simulations are flown before, and even during a flight to negotiate changing weather. Winds aloft often make the aircraft fly backwards or stationary (relative to the ground), but winds that can adversely affect the Pathfinder usually diminish above 30,000 ft.

Pathfinder mostly flies by autopilot, with a pilot and flight test engineer commanding the mission from the ground. Although the pilot has a control stick, the aircraft is usually "flown" using rotary switches that change aircraft headings and turn rates via the autopilot. It is described as an easy plane to land: its normal descent rate of 70 fpm is lowered (by throttle) to 40 fpm and the plane was steered into the wind until touchdown.

Other Links

Pathfinder Movies
Pathfinder Project Home Page
Pathfinder Fact Sheet

ERAST Program Home Page
ERAST Fact Sheet




Last Modified: April 14, 2000
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