Solar plane soars toward lofty goal

A prototype of the Helios flying wing taking off for its first test flight on solar power on Kauai, Hawaii, July 14, 2001.

By Richard Stenger
CNN

(CNN) -- The odd-looking prototype of an aircraft that could someday fly on Mars took wing on Monday in an attempt to break an aviation altitude record on Earth.

The unmanned Helios plane could soar as high as 100,000 feet during a flight over Hawaii expected to last more than half a day, according to NASA project managers. The elevation is three times higher than the cruising altitude of commercial jets.

The air pressure at such lofty heights is thought to resemble the thin atmosphere near the surface of Mars, according to NASA's Dryden Flight Research Center, which oversees the program.

Helios test flights should provide valuable information about how to design airplanes that can navigate the martian skies, said Dryden spokesman Fred Johnson.

"Some of the data will be on-the-job learning for flying in an atmosphere with very little oxygen or other atmospheric constituents. It's really close to outer space, but has enough gas to support conventional flight," he said.

The remote-controlled plane boasts a wingspan longer than a Boeing 747, weighs less than many automobiles and uses 14 solar-powered motors to putter along at about 20 mph.

Eventually such an aircraft could remain aloft for months, offering an inexpensive alternative to low-orbit satellites to gather and transmit data from the edge of space, NASA scientists said.

Weather and technical problems postponed numerous attempts to fly the $15 million craft, essentially a flying wing that extends 247-feet.

On Monday, Helios took off from the island of Kauai shortly before 9 a.m. Hawaiian time (3 p.m. EDT) and should return within 14 to 16 hours. The location takes advantage of long summer sunlight hours to maximize the available solar power.

In a July test flight, Helios reached about 76,000 feet.

In a 1966 spy mission, a SR-71 Blackbird set the current record for sustained horizontal flight for a jet or propeller powered aircraft, 85,068 feet.