Video: First all-solar airplane passes preliminary runway test

The Solar Impulse team has promised to go "around the world in a solar airplane," and the first steps with a prototype aircraft have been recorded.

The aircraft is designed to be the first to fly around the world powered only by the sun, and as you can see in the videos below, it's completed its first taxi tests down a Swiss runway.

The aircraft has four electric motors that run purely on sunlight.

By any measure, preliminary tests were slow, and the plane only managed about 10 knots, or 11.5 miles per hour.

The team used safety gear to protect the aircraft in case of a failure of the landing gear, but the aircraft was able to taxi without the use of the safety gear.

The next taxi tests are expected to show the aircraft speeding to about 20 knots, which is fast enough for liftoff, for brief "flea hops." First true flights are expected in early 2010.

This post was originally published on Smartplanet.com