Helios leaving Kauai, heading to California

SPECIAL TO TGI

With a new world altitude record to their credit, engineers and technicians for AeroVironment Inc., are preparing to disassemble and pack the solar-powered Helios Prototype for shipment back to California from Kaua’i.

The unmanned craft established an unofficial record of 96,500 feet in sustained horizontal flight during an almost 17-hour flight from the Navy’s Pacific Missile Range Facility last Monday. Only short-duration, rocket-powered planes such as the X-15 of the 1960s have flown higher.

The new mark is subject to certification by the National Aeronautics Association, the certifying agency for all aviation records in the U.S.

John Del Frate, solar aircraft project manager at NASA Dryden Flight Research Center, said the aircraft and most of the crew will depart Kaua’i by next weekend.

The Helios will be placed in storage while development work continues on a regenerative energy storage system designed to allow the aircraft to fly at night on excess power generated by solar panels during the day.

A flight-worthy system is expected to be ready for installation and flight tests in 2003. Those tests are aimed at achieving a NASA milestone of flying continuously for four days and nights above 50,000 feet.

Designed and built by AeroVironment, of Monrovia, Calif., the ultra-lightweight Helios (with a wingspan of 246 feet, its gross weight was 1,557 pounds on this flight) is believed capable of reaching altitudes of 100,000 feet under ideal weather conditions.

Conditions for last Monday’s flight were far from ideal. Del Frate noted that low clouds which delayed the takeoff by almost an hour limited the maximum altitude, since it shortened the time available for ascent to a little over seven hours. Weather also contributed to an encounter with severe turbulence during the first hour of flight, but as it had done on a flight July 14, the Helios rode out the rough air.

Officials said last Monday’s demonstration flight was performed to validate the Helios’ capability as a platform for high-altitude earth monitoring and atmospheric sampling missions.

“There were a few weak areas, but in general, it came together very well,” Del Frate said.

During a post-flight debriefing he described as emotional, “the crew expressed elation, jubilation, a lot of emotion about achieving the record and being part of an incredible team,” he added. “It was a good meeting, a good moment for the team, good closure.”

Development of the Helios is being funded and managed under NASA’s Environmental Research Aircraft and Sensor Technology project.

Helios got help from the Ni’ihau Ranch helicopter and an up-looking fish-eye camera mounted on Helios to avoid flying under clouds during the historic flight, said Bob Curtin, a vice president of AeroVironment.

Greg Kendall was at the “pilot” at the remote controls as Helios broke the altitude record set by the Lockheed SR-71 in 1976.

The record flight was witnessed by Stanley Nelson, chairman of the National Aeronautic Association’s contest and records board.

At peak altitude, several stars were visible through the fish-eye camera. At one point, the aircraft was above 99 percent of Earth’s atmosphere.

One of the more “under-appreciated systems” that worked flawlessly was the heating and cooling system that maintains acceptable avionics temperatures while the environment changes drastically during the climb. The temperature of the atmosphere went from about 80 degrees Fahrenheit at sea level to a minimum of about minus-85 at 58,000 feet.

The true airspeed of Helios was about 21 miles per hour during takeoff and reached about 170 mph at peak altitude. At 170, Helios was flying at about Mach 0.25 on solar power.

The descent lastesd 9.5 hours. Total flight time was 16 hours and 54 minutes.

Officials and volunteers from AeroVironment, NASA, PMRF, ITT, SunPower, HTS, KAS, Ni’ihau Ranch, AmTech and Kauai Community College helped make “this achievement possible,” Curtin said.