NASA's Solar-Powered Aircraft Begins Science Missions In Hawaii

Pathfinder, NASA's solar-powered, remotely piloted aircraft, has begun conducting a series of up to four science mission flights to highlight the aircraft's science capabilities while collecting imagery of forest and coastal zone ecosystems on Kauai, Hawaii.

    Remotely piloted aircraft similar to Pathfinder could spend long periods of time over the ocean, monitoring storm developments to provide more accurate predictions of hurricanes.  These aircraft also could be used to monitor major croplands, forests and other large, remote expanses to provide early warning of crop damage or fires.

    The Pacific Missile Range Facility at Barking Sands, Kauai, is the staging base for these flights as part of NASA's Environmental Research Aircraft and Sensor Technology (ERAST) program, based at NASA's Dryden Flight Research Center, Edwards, CA.  Kauai was chosen as an optimum location for testing Pathfinder due to high levels of solar irradiance, available airspace and radio frequency, and diversity of terrestrial and coastal ecosystems.

    Major science activities of Pathfinder, the first flight of which occurred on Oct. 25, include detection of forest nutrient status, forest regrowth from Hurricane Iniki, sediment/algal concentrations in coastal waters and assessment of coral reef health.  The science activity is being coordinated by NASA's Ames Research Center, Moffett Field, CA, and involves researchers at the University of Hawaii and University of California.  The flights will conclude just before Thanksgiving.

    The flights will test two new scientific instruments, a high spectral resolution Digital Array Scanned Interferometer (DASI) and a high spatial resolution Airborne Real-Time Imaging System (ARTIS).  The remote sensor payloads were designed by Ames to support NASA's Mission to Planet Earth science programs.  The flights will be conducted at altitudes between 22,000-49,000 feet.

    "This will be the first time that we have flown these two new sensor systems," said Steve Wegener, Ames' manager of the payloads and science element of the program.

    DASI, a remote sensing instrument that looks at reflected spectral intensities from the Earth, will be used to study such things as plant stress, constituents in coastal zone waters and coral reef health.  Measuring 30 inches long and ten inches in diameter, DASI weighs less than 25 pounds and mounts beneath Pathfinder's wing.

    The ARTIS payload is built around a digital camera, which has a six-million-pixel array, enabling it to take high quality digital photographs.  The camera has a variety of potential science and commercial applications, such as documenting flood surges, geologic features and crop stress, according to Wegener.

    Both sensors are designed to be small, lightweight and interactive, in compliance with ERAST program goals of miniaturizing flight payloads.  "These new sensor technologies are being developed for use in the next generation of remotely piloted aircraft," Wegener said.  These and other new sensor systems are designed to complement high altitude studies of atmospheric ozone, land-cover change and natural hazard studies conducted by NASA's Earth Resources Survey aircraft.

    Pathfinder recently set an altitude record for propeller-driven flight of over 71,500 feet.  "Pathfinder's performance to date has exceeded our wildest expectations," said the programÕs manager Jenny Baer-Riedhart.  "We beat our altitude milestone by 6,500 feet in the first two flights this summer and demonstrated the capability for science mission demonstrations in a remote, tropical location."

    Pathfinder is one of several remotely piloted aircraft being evaluated under the ERAST program.  The program focuses on developing technologies required to operate subsonic unpiloted aircraft at high altitude for long-duration flights.

    "Remotely piloted aircraft have the potential to do the dull, dirty and dangerous missions where you wouldn't want to put a pilot at risk," Wegener said.

    Pathfinder is a flying wing with a span of 99 feet.  Small pods extending below the wing's center section can carry a variety of scientific sensors.  Solar arrays on the upper wing surface can provide as much as 7,200 watts of power at high noon on a summer day to power the craft's six electric motors and other electronic systems.  A backup battery system can provide power for up to five hours to fly the craft after sundown.  Pathfinder was designed, manufactured and is operated by AeroVironment, Inc., of Simi Valley, CA, under a jointly sponsored research agreement with NASA.