The Solar Impulse plane completed its first international flight on May 13, 2011, soaring from its Switzerland pad to Brussels, taking about 13 hours, free of any need for fuel, capturing energy without emitting pollution.
The experimental emissions-free Solar Impulse HB-SIA covered the 480 kilometer (300 mile) route to Brussels from its home in western Switzerland with graceful ease, winging over France and Luxembourg on the way at an altitude of 3,600 meters (11,880 feet), according to the aircraft's team.
The wingspan of the Solar Impulse is airliner-sized, but the aircraft is no heavier than the average family car.
In July 2010 the Solar Impulse became the first human-piloted airplane to fly 24 hours on solar energy alone, requiring no additional fuel to stay aloft through the night. Last summer's flight set endurance and altitude records for a human-piloted, solar-powered aircraft after the Solar Impulse flew 26 hours, 10 minutes and 19 seconds, at an altitude of 9,235 meters (30,298 feet).
After that, this high-tech green airplane completed several more test flights between Geneva and Zurich.
But flying into the busy Brussels airport was another first, and a key test of the plane's performance as it navigated through crowded airspace.
The four 10-horsepower electric motors that drive the HB-SIA's four propellers are charged by 12,000 solar cells fixed on both its 64-meter (200-foot) wings. So far, as the July 2010 test flight demonstrated, the system can store enough sunlight-generated energy to keep the plane flying over a summer night without falling back on another power source.
Speed is not on the team's list of goals, but drawing attention to the possibilities of green high-tech flying is a top priority.
This Solar Impulse HB-SIA is on display at the Brussels airport until May 29. Its next gig will be a flight to the international Paris Air Show, held June 20 to 26 at Le Bourget airport.
Much longer flights, definitely transatlantic and trans-american journeys, are in the team's near-future plans for the Solar Impulse, all in preparation for a round-the-world bid, probably in a slightly bigger aircraft, perhaps in two or three years.