The Solar Impulse, a solar-powered plane created by explorer Bertrand Piccard and engineer André Borschberg, is a delicate creature. It’s so lightweight that it can only fly in the most calm weather, when turbulence is non-existent. But the weather was perfect for the plane’s flight this week over San Francisco’s Golden Gate bridge. The flight marks the beginning of Solar Impulse’s cross-country journey, set to end in early July at JFK Airport in New York City.
Piccard described earlier this year to Co.Exist what it’s like to fly a solar-powered plane: "If you fly it like a normal airplane you overcontrol, you cannot steer and land. You need to learn how to be extremely careful, make little moves with the control, and wait until a reaction comes. You have to anticipate enormously, and it’s not very stable, so you need to fly with the rudders."
The plane, which is covered in 12,000 solar cells that store energy in a lithium polymer battery, can go only go 35 mph on a good day. But Piccard and Borschberg are already working on a second version of the Solar Impulse with upgraded features. That plane is expected to make a round-the-world trip in 2015.
Solar Impulse will make 10 stops before winding down in New York City—check here to see if you’ll get to watch it slowly cruise the skies in person.