Prototype Solar Plane Crashes

Helios, the solar-powered, remotely controlled aircraft that shattered the world altitude record two years ago, crashed near the Hawaiian island of Kauai on Thursday during a test flight.

The $15-million airplane was designed by Paul MacCready’s aerospace firm AeroVironment Inc. in Monrovia. The craft was flying over the U.S. Navy’s Pacific Missile Range Facility when it “broke apart,” a spokesman for the National Aeronautics and Space Administration said.

It was not clear what caused the airplane to break up. It was aloft about 29 minutes and was hovering at about 8,000 feet when it crashed into the Pacific Ocean, a NASA official said. A chase helicopter recorded the breakup on video, the official said.

The aircraft, an elongated wing-shaped craft laden with thousands of solar panels and powered by 14 propeller motors not much stronger than a hair dryer, was at the heart of NASA’s efforts to develop a high-altitude, long-duration plane that could stay aloft for months.

In August 2001, powered only by the sun’s energy, Helios climbed to 96,863 feet, shattering a 25-year-old flight record. The previous record of 85,068 feet was reached in 1976 by a jet-powered SR-71 spy plane, the world’s fastest jet.

NASA was hoping next month to have Helios attempt another record by flying continuously for 40 hours. The plan was for the plane to first use solar power and then rely on a new experimental fuel cell that could store solar energy during the day and use it to power the aircraft at night.

NASA spokesman Alan Brown said the space agency was “committed to continuing the technology development,” and probably would fund a replacement.

A team of officials from NASA, AeroVironment and the Navy will investigate the accident, Brown said.