Following a bicycle down the runway at Moffett Field in Mountain View, Calif., a solar-powered airplane took off on a coast-to-coast voyage across the U.S. this morning to promote the message of clean technology.
Piloted by Swiss aviator Bertrand Piccard, the Solar Impulse HB-SIA set off for Phoenix, Ariz., on the first leg of its Across America journey that will also take the slender craft to Dallas, St. Louis, Washington, D.C., and finally New York in early July.
The goal is to go from one end of the country to the other without using a drop of fuel.

Sporting 12,000 solar cells, Solar Impulse can fly both day and night. It has a wingspan of a large passenger jet, at 208 feet, and the weight of a small car at 3,527 pounds.
Although its 881 pounds of lithium batteries only supply it with the power of an average scooter, the HB-SIA plane can fly for up to 26 hours at a stretch. Its average speed is 40 mph.
Launched in 2010, the craft made its first international flight from Switzerland to Brussels in 13 hours, followed by a 1,550-mile journey from Madrid, Spain, to Morocco's Rabat.
The Solar Impulse team hopes to fly the HB-SIA around the world in 2015, but meanwhile you can follow it on the Across America tour here. There's live cockpit footage as well as mapping and flight data from the craft here.
Check out some close-up pics of Solar Impulse from CNET's recent visit in the gallery below.