Solar Impulse Plane Attempts Crucial Night Flight

ZURICH, Switzerland (July 7) -- A solar-powered plane is attempting a key flight test in the skies of Switzerland, with its inventors saying it could set a milestone for flying around the world using only the clean and renewable energy of the sun.

The carbon fiber Solar Impulse prototype, with the 262-foot wingspan of an Airbus A340 and the weight of a middle-sized car, took off shortly before 7 a.m. today from the Payerne airbase with a solo pilot at the controls, the Solar Impulse team said.

The plan is to have the aircraft up in the air throughout the day to allow its 12,000 solar panels to soak up as much energy as possible, charging the batteries enough to keep the plane aloft through the dark of night. If successful, it will be the world's first night flight with a solar plane.

"For seven years now, the whole team has been passionately working to achieve this first decisive step of the project," said Andre Borschberg, the CEO and co-founder of the Solar Impulse project, shortly before strapping himself into the cockpit.

Borschberg brought the plane up to an altitude of 28,000 feet, where he planned to cruise until the sun rays begin to weaken about two hours before sunset. The aircraft will then start a slow descent, reaching an altitude of around 5,000 feet by 11 p.m., the team said, and then carry on flying until dawn the next day. If he pulls it off, Borschberg will have completed the longest and highest flight ever made by a solar plane.

A successful day-and-night cycle is a vital step toward the Solar Impulse project's ultimate goal of circumnavigating the earth. The team plans to construct a slightly larger version of the current plane, which would stay in the air for as long as five days and nights at a time, landing only to switch pilots.

The Solar Impulse team initially scheduled the night flight for earlier this month, but a technical problem involving a transmitter forced the group to reschedule. The flight's progress can be followed live on the Solar Impulse website.

The Solar Impulse project, initiated in 1999 by Bertrand Piccard following his circumnavigation of the world in a balloon, was launched to demonstrate the potential of renewable energy and clean technologies and the feasibility of flying without polluting.