Technicians are preparing the flying-wing, solar-powered plane Helios for another test flight.
If Westside weather and all the technical aspects of the Helios prototype are ready the flight is expected to takeoff at about 8:30 a.m. Thursday from the runway at the Pacific Missile Range Facility on the Mana Plain north of Kekaha.
The flight could last for about 20 hours, and the Helios would land on the Barking Sands runway at PMRF.
If the flight is delayed, the back-up dates are Friday and Saturday.
The overall goal of the flight series being held at PMRF this summer is to demonstrate the ability of the Helios Prototype to fly a long-endurance mission of about 40 hours aloft, including at least 14 hours above 50,000 feet altitude.
In daylight hours, the Helios flies on electrical power derived from solar arrays. At night an experimental fuel cell system is being tested that combines oxygen from the atmosphere with hydrogen stored on the aircraft. This would allow the aircraft to stay aloft overnight, and for fairly long periods of time without landing.
If the tests are successful, it will mark the first time that a large aircraft is powered by electricity derived from an advanced experimental fuel cell system. The success of the system would also be a boost for proponents of hydrogen power, a fuel supply that some say would offer a non-polluting, locally-produced alternative to burning fossil fuels for energy.
John Del Frate, Helios project manager at NASA’s Dryden Flight Research Center located in the high desert of California, said the primary objective of the second check flight is to verify the in-flight operation of the fuel cell system, including stable operation of the system and its compressor at 50,000 feet altitude and at a rated power of 18.5 kW.
A rapid shutdown of the fuel cell system and a restart at night on battery power is also planned.
During the first check flight of this series of test flights, made on June 7 at PMRF, the Helios Prototype was aloft for about 15 hours at altitudes up to 52,000 feet. During the flight engineers checked out modifications and upgrades made to the aircraft over the past two years.
Two summers ago an initial series of Helios test flights helped prove the feasibility of using the solar-powered flying wing for military and civilian uses.
The experimental fuel cell system was not brought on-line due to leakage in the coolant system and compressed air lines that feed the fuel cell while the Helios is aloft.