Piloted solar plane unveiled
The vehicle, spanning 61m but weighing just 1,500kg, will undergo trials to prove it can fly through the night.
The width of a jet airliner, but the weight of a family car, it is possibly the lightest plane (weight-for-size) ever to fly.
When trials have finished - including a transatlantic flight planned for 2012 - the single-seat plane (designated "HB-SIA") should be able to circumnavigate the globe non-stop. Unfortunately, the pilot won't - at 20-25 knots, the flight should take three weeks, too long for a human to go without sleep. Instead, the flight is planned in five-day "hops", each ending with a change in pilot.
Solar Impulse website
BBC Story with video