Solar plane crosses Pacific to Bay Area on trip around the world

Solar Impulse 2 flies over San Francisco on Saturday, April 23, 2016. The solar-powered airplane, which is attempting to circumnavigate the globe to promote clean energy and the spirit of innovation, arrived from Hawaii after a three-day journey across the Pacific Ocean. (AP Photo/Noah Berger) less Solar Impulse 2 flies over San Francisco on Saturday, April 23, 2016. The solar-powered airplane, which is attempting to circumnavigate the globe to promote clean energy and the spirit of innovation, arrived ... more Photo: Noah Berger, Associated Press Photo: Noah Berger, Associated Press Image 1 of / 39 Caption Close Solar plane crosses Pacific to Bay Area on trip around the world 1 / 39 Back to Gallery

A solar-powered airplane flew over the Golden Gate Bridge on Saturday, offering San Franciscans a rare glimpse of the aircraft as it completed its flight over the Pacific Ocean as part of an attempt to circumnavigate the world.

The Solar Impact 2, which left Hawaii on Thursday, had already been in flight for about 56 hours when it made its first pass over the landmark bridge.

“I crossed the bridge. I am officially in America,” pilot Bertrand Piccard declared Saturday evening as the plane circled past the Golden Gate and over the Presidio. He was broadcasting live in an online video feed documenting the journey.

Down below, residents of the Outer Richmond and the Sunset neighborhoods snapped photos of the solar plane on its historic flight.

The plane made its way to Moffett Federal Airfield in Mountain View, where it landed at 11:45 p.m. Saturday. The pilots will recharge before the next leg of their journey, to the central U.S., then onward to New York before crossing the Atlantic Ocean.

Piccard has said that stopping in Silicon Valley is of symbolic importance, linking his daring around-the-world journey with the spirit of innovation and technology for which the area is known.

The aircraft, which is equipped with 17,000 solar cells that power the plane’s propellers and charge its batteries, can continue to run on stored energy after the sun sets. Piccard and his co-pilot, André Borschberg, who followed Piccard over the Golden Gate in a red helicopter Saturday, began their journey in Abu Dhabi on March 9, 2015. So far, the plane has crossed half the globe, with stops in Oman, India, Myanmar, China, Japan and, most recently, Hawaii.

On July 3, 2015, Borschberg completed a historic five-day, five-night pass over the Pacific Ocean from Japan to Hawaii without using any fuel. The team was later delayed in Hawaii because of damage the battery system had suffered along the way.

The plane is able to fly nearly nonstop powered exclusively by the energy of the sun, according to the crew. Over populated areas, the pilots do not sleep. But over the oceans, they take short naps of up to 20 minutes at a rate of one to 12 times per day.

The solar aircraft is slow-moving — typically flying about 28 mph — though it can pick up speed midday when the sun’s rays are strongest. Its long, narrow, 5,000-pound body is made of carbon fiber. It has an unusually long wingspan of 236 feet — about 13 feet longer than a Boeing 747.

The Associated Press contributed to this report.

Marissa Lang is a San Francisco Chronicle staff writer. Email: mlang@sfchronicle.com Twitter: @Marissa_Jae