A prototype solar-powered plane has made its first full test flight – coming closer to the goal of using solar energy to fly around the world.
The Solar Impulse, with a wingspan similar to that of a super-jumbo jet but weighing the same as a saloon car, took off from a Swiss airfield.
The plane’s wings are covered by solar cells which power four electric motors.
Its designers hope a slightly larger production model will circumnavigate the globe in two years’ time.
The test flight was intended to verify that the plane’s behaviour tallied with simulations.
“With such a large and light plane never having flown before, the aircraft’s flight behaviour remains unexplored,” the flight team said in a statement.
Round-the-world balloonist Bertrand Piccard is leading the project and intends to pilot the plane along with co-founder Andre Borschberg.
“It’s a very important moment after seven years of work,” said Mr Borschberg before the take-off.
Witnesses said both take-off and landing seemed to go smoothly.
The flight team have been conducting flea-hop tests since December, taking the plane no higher than 60cm (2ft) in altitude and 300m in distance.
A night flight is planned later this year, and then a new plane will be built based on the results of those tests.
The big take-off is planned for 2012, when the two pilots will try a transatlantic flight before attempting to circumnavigate the globe.