Helios Prototype Flying WingTechnicians for AeroVironment, Inc., jack up a pressure tank to the wing of the Helios Prototype solar-electric flying wing. The...Closeup of the Helios Prototype, the latest and largest example of a slow-flying ultralight flying wing designed for high-altitude, long-duration...Aerovironment technicians carefully line up attachments as a fuel cell electrical system is installed on the Helios Prototype solar powered...The first flight of a large aircraft to be powered by electric fuel cells began with a takeoff at 8:43...The Helios Prototype is an enlarged version of the Centurion flying wing, which flew a series of test flights at...The solar-powered Helios Prototype flying wing frames two modified F-15 research aircraft in a hangar at NASA's Dryden Flight Research...The Helios Prototype aircraft during initial climb-out to the west over the Pacific Ocean.The Helios Prototype aircraft at approximately 10,000 feet flying above cloud cover northwest of Kauai, Hawaii.The first flight of a large aircraft to be powered by electric fuel cells began with a takeoff at 8:43...The solar-electric Helios Prototype flying wing is shown near the Hawaiian islands of Niihau and Lehua during its first test...The first flight of a large aircraft to be powered by electric fuel cells began with a takeoff at 8:43...Technician Marshall MacCready carefully lays a panel of solar cells into place on a wing section of the Helios Prototype...Technician Marshall MacCready carefully lays a panel of solar cells into place on a wing section of the Helios Prototype...An engineer at AeroVironment's Design Development Center in Simi Valley, California, closely inspects a set of silicon solar cells for...Helios Prototype on lakebed prior to first battery-powered flightA technician at AeroVironment's Design Development Center in Simi Valley, California, checks a panel of silicon solar cells for conductivity...The first flight of a large aircraft to be powered by electric fuel cells began with a takeoff at 8:43...The first flight of a large aircraft to be powered by electric fuel cells began with a takeoff at 8:43...Helios Prototype Flying Wing flying above Rogers Dry Lake at Edwards, CA.The Helios Prototype is an enlarged version of the Centurion flying wing, which flew a series of test flights at...The 247-foot length of the Helios prototype wing is in evidence as the high-altitude, solar-powered flying wing rests on its...NASA's Helios Prototype aircraft taking off from the Pacific Missile Range Facility, Kauai, Hawaii, for the record flight. As a...Ground crewmen maneuver AeroVironment's solar-powered Helios Prototype flying wing on its ground support dolly during functional checkouts prior to its...Ground crewmen maneuver AeroVironment's solar-powered Helios Prototype flying wing on its ground support dolly during functional checkouts prior to its...The Helios Prototype flying wing stretches almost the full length of the 300-foot-long hangar at NASA's Dryden Flight Research Center,...Helios Prototype Flying Wing performing a test flight over Rogers Dry Lake at Edwards, Calif.The Helios Prototype is an enlarged version of the Centurion flying wing, which flew a series of test flights at...Helios Prototype Flying Wing performing a low-altitude test flight over Rogers Dry Lake at Edwards, Calif.The solar-electric Helios Prototype flying wing is shown over the Pacific Ocean during its first test flight on solar power...The Helios Prototype is an enlarged version of the Centurion flying wing, which flew a series of test flights at...The Helios Prototype is an enlarged version of the Centurion flying wing, which flew a series of test flights at...Helios Prototype Flying Wing taking off.The takeoff set the stage for a two-day Helios endurance flight in the stratosphere planned for mid-July. The Helios wing,...The solar-electric Helios Prototype flying wing is shown over the Pacific Ocean during its first test flight on solar power...The solar-electric Helios Prototype flying wing is shown near the Hawaiian island of Niihau during its first test flight on...The solar-electric Helios Prototype flying wing is shown near the Hawaiian islands of Niihau and Lehua during its first test...Helios Prototype crew chief Marshall MacCready of AeroVironment, Inc., carefully monitors motor runs during ground checkout of the solar-powered flying...Ground crewmen maneuver AeroVironment's solar-powered Helios Prototype flying wing on its ground support dolly during functional checkouts prior to its...The Helios Prototype aircraft in a northerly climb over Niihau Island, Hawaii, at about 8,000 feet above sea level.Ground crewmen maneuver AeroVironment's solar-powered Helios Prototype flying wing on its ground support dolly during functional checkouts prior to its...