Sidebar: Solar Flier Climbs Higher

sidebar: solar flier climbs higher

Engineers and scientists from NASA and Aerovironment of Monrovia, Calif., were gathering at press time at a missile range in Hawaii to attempt the launch of a solar-powered, unmanned airplane, Helios, to a record altitude of 100,000 feet. In 1998, Pathfinder Plus, Helios's predecessor, set the current high flight record for an airplane of 80,000 feet.

NASA has several goals for the Helios project. By flying at this extreme altitude, the agency hopes to get a sense of the flying conditions on Mars. The Helios is expected to carry a 100-lb. payload and thus demonstrate an ability to carry loads up to 600 lbs. to 70,000 feet, offering an alternative to meteorological and atmospheric monitoring by satellite. Another goal of the project is to demonstrate the feasibility of long-term flight, one in which the time spent aloft is counted in months.

Helios's maker, Aerovironment, has already formed a subsidiary to commercialize the technology. Skytower Inc. sees the Helios and similar solar-electric aircraft as an ideal way of providing telecommunications service to residents of Earth. Compared with satellites, a Helios-style craft could offer many times more broadband capacity with lower launch-loss risk. And atmospheric satellites could compete with land-based stations through lower cost, faster deployment, and easier relocation.

If the high-altitude flights go well, NASA will begin fitting the craft with fuel cells to enable flights of longer duration. The fuel cells will use oxygen and hydrogen generated during the day to keep the airplane flying through the night. The test of this part of the project is anticipated for 2003, when plans call for a 96-hour flight at 50,000 feet.