Solar-powered plane flies across the Pacific

A solar-powered plane has completed a three-day, non-stop flight across the Pacific Ocean without using any fuel, marking a milestone in renewable energy. The aircraft is built mainly of carbon fibre and is entirely powered with 17,248 solar cells on its wings that recharge four lithium polymer batteries; it weighs just over 5,070 pounds, which is nearly 200 times lighter than a Boeing 747. As we have previously noted, airlines are now being hit by climate change regulations as they account for about 2% of global emissions, though analysts believe these emissions will triple by the middle of the century due to the expected growth in air travel. 

Story highlights Pioneering solar plane lands safely in the continental U.S. "Nobody's done this before. There's no guidebook," director says The flight's mission is to showcase the power of clean technology

CNN —

An experimental plane flying around the world without a single drop of fuel landed in California after a two-and-a-half day flight across the Pacific.

Piloted by Swiss explorer and psychiatrist Bertrand Piccard, Solar Impulse 2 touched down in Mountain View just before midnight (3 a.m. ET).

“It’s a new era. It’s not science fiction. It’s today,” Piccard told CNN from California after his successful voyage. “It exists and clean technologies can do the impossible.”

Images of the elegant solar aircraft, which has the wingspan of a Boeing 747 but only weighs about as much as an SUV, flying over the Golden Gate Bridge into San Francisco Bay mark a significant achievement. The team has seen the project beset with problems and setbacks during its pioneering airborne circumnavigation.

“I’m very happy that everything works extremely well and the airplane is functioning as it should,” Piccard’s business partner and the plane’s other pilot, Swiss engineer Andre Borschberg, told CNN by phone from California just ahead of the successful, on-schedule landing.

“It’s a demonstration that the tech is reliable.”

An experimental plane trying to fly around the world without a single drop of fuel took off from Hawaii on Thursday, resuming a journey that had stalled on the island of Oahu for almost 10 months.

Solar Impulse 2, seen above the Pyramids of Giza on its approach to Cairo, Egypt. Solar Impulse 2 Solar Impulse 2 aircraft lands at Sevilla airport on June 23, 2016, after a 71-hour journey from New York powered only by sunlight. CRISTINA QUICLER/AFP/AFP/Getty Images The Spanish Air Force's Patrulla Aguila formation team performs past the sun-powered Solar Impulse 2 aircraft arriving few moments before landing at Sevilla airport on June 23, 2016. CRISTINA QUICLER/AFP/AFP/Getty Images Solar Impulse 2 sits on the runway at JFK international airport prior to departing to cross the Atlantic on June 20, 2016. Solar Impulse/Revillard/Rezo.ch Solar Impulse 2 flies over the Golden Gate Bridge as part of a fly-by of the San Francisco Bay after flying for two and half days from Hawaii. Solar Impulse Solar Impulse 2 departs Hawaii for the two-and-a-half day flight to California, the 9th leg of its round-the-world trip. JEAN REVILLARD/REZO Pilot Bertrand Piccard prepares to take off from Kalaeloa Airport, Hawaii on April 21st 2016, en route to California. The round-the-world solar flight will take 500 flight hours and cover 35,000 km. JEAN REVILLARD/REZO The Solar Impulse 2 is seen at the Kalaeloa Airport in Kapolei, Hawaii, on Friday, July 3. The solar-powered plane, alternately piloted by Andre Borschberg and Bertrand Piccard, is attempting to fly around the world without fuel. Marco Garcia/AP Borschberg approaches Honolulu Airport on July 3 after a record-breaking five-day journey across the Pacific Ocean from Japan. Jean Revillard/Solar Impulse 2/AP Solar Impulse is seen at sunrise on Monday, June 29, shortly after taking off from the international airport in Nagoya, Japan. The aircraft's Japan-to-Hawaii trip was the most ambitious leg of its quest to circumnavigate the globe powered only by the sun. SOLAR IMPULSE/AFP/Getty Images The solar-powered plane prepares to take off from Nagoya on June 29. Jean Revillard/SI2/Global Newsroom/Getty Images A mobile hangar is opened on Tuesday, June 23, as the plane is prepared for a possible takeoff. The plane had been waiting in Japan for three weeks because of bad weather. TOSHIFUMI KITAMURA/AFP/Getty Images The mobile hangar at the Nagoya airport, as seen on Wednesday, June 3. TOSHIFUMI KITAMURA/AFP/Getty Images The Solar Impulse 2 touches down in Nagoya on Monday, June 1. The plane made an unscheduled stop after mission controllers decided the weather was not right for the plane to cross the Pacific Ocean. TOSHIFUMI KITAMURA/AFP/Getty Images People take pictures as the plane takes off from Nanjing, China, on Sunday, May 31. JOHANNES EISELE/AFP/Getty Images Piccard sits in the cockpit right after landing in Chongqing, China, on Sunday, March 31. He had just completed the fifth leg of the global trip. Solarimpulse Borschberg and Piccard are welcomed by a crowd of reporters after landing in Chongqing. Solarimpulse The Solar Impulse 2 is rolled out of its inflatable mobile hangar before leaving Myanmar for Chongqing on Monday, March 30. Solarimpulse The plane is prepared on a tarmac in Ahmedabad, India, on Wednesday, March 18. Solarimpulse The Solar Impulse 2 flies over Muscat, Oman, after taking off on Tuesday, March 10. Solarimpulse The plane takes off from Abu Dhabi, United Arab Emirates, on Monday, March 9. Its flight to Oman was the first leg of its round-the-world flight. Jean Revillard/Getty Images The plane is the brainchild of Swiss pilots Piccard, right, and Borschberg. FABRICE COFFRINI/AFP/Getty Images The top surface of the Solar Impulse 2's wings is covered with 17,000 solar cells that supply four electric motors with renewable energy. Its batteries can store enough solar daytime energy to keep the plane moving throughout the night. © Solar Impulse | Revillard | Rezo.ch The plane's wings stretch for a massive 72 meters (236 feet). © Solar Impulse The plane's cockpit has been designed to ensure that a pilot can live there for a week. FABRICE COFFRINI/AFP/Getty Images Solar Impulse 2 is the upgraded version of a prototype, pictured here, that made history in 2010 by becoming the first solar aircraft capable of flying overnight. DOMINIC FAVRE/AFP/Getty Images/file Solar Impulse 1, pictured here over Lake Geneva, broke several records, including the world's first fully solar-powered intercontinental flight in 2012. JEAN REVILLARD/AFP/Getty Images/file Borschberg is an engineer who studied management science at the Massachusetts Institute of Technology. The aviation enthusiast has been involved in several startups and technology projects over the years. © Solar Impulse | Revillard | Rezo.ch Piccard, who is also a doctor and a psychiatrist, is the first man to fly around the world non-stop in a balloon. He hails from a family of scientists and explorers. © Solar Impulse | Revillard | Rezo.ch Piccard's grandfather, Auguste Piccard, was a physics professor who helped pave the way for high-altitude navigation by inventing the pressurized cabin. He was also the first person to reach the stratosphere in a balloon. © Piccard Family Piccard's father, Jacques, was the first man to dive to the bottom of the Marianas Trench -- the deepest point of the world's oceans. © Piccard Family Solar Impulse 2's round-the-world journey Prev Next

The Solar Impulse 2, piloted by Swiss explorer and psychiatrist Bertrand Piccard, lifted off just before sunrise to cheers and applause.

As dusk fell over the city, the team posted striking images on its social media accounts.

BREAKING: a solar airplane flying without fuel above #SF at night to promote #futureisclean ! pic.twitter.com/eNAbdfnkK4 — Solar Impulse Foundation (@solarimpulse) April 24, 2016

It will head for the San Francisco Bay area, some 4,000 kilometers (2,500 miles) away. And because the plane travels at about the same speed as a car, the Hawaii-California leg will take about 62 hours to complete.

While Piccard was at the controls for this ninth leg of the round-the-world trip, he and Borschberg, take turns flying the plane solo.

“It’s a very stable weather window,” Solar Impulse spokeswoman Alexandra Gindroz said.

That forecast will be a relief for Piccard and his business partner, Swiss engineer Andre Borschberg, who take turns flying the plane solo.

Solar Impulse 2 makes history 01:49 - Source: CNN

After all, it’s the weather – particularly the sun – that ultimately decides the schedule of this journey, even with dozens of engineers and experts monitoring the plane’s every move.

After all, it’s the weather – particularly the sun – that ultimately decides the schedule of this journey, even with dozens of engineers and experts monitoring the plane’s every move.

“Nobody’s done this before,” managing director Gregory Blatt said. “There’s no guidebook. There’s no best practice.”

The team has learned this the hard way.

Rolling with the punches

The Solar Impulse 2 was originally supposed to land in Abu Dhabi, where it started its journey in March 2015, by the end of last summer.

Solar-powered plane lands in Hawaii 01:53 - Source: CNN

But a series of frustrating weather delays in China slowed progress for weeks, followed by an unexpected diversion to Japan, where the aircraft was damaged on the tarmac by a storm.

Still, the pilots and their team of more than 100 pushed onward, repairing the aircraft and preparing it for what they called “the moment of truth” – the Pacific crossing to Hawaii.

It was a moment of human achievement. For almost five days and five nights, Borschberg piloted the plane wearing an oxygen mask as it climbed up 8,000 meters (5 miles) high during the day, its solar cells soaking up enough energy to propel the aircraft through the night.

‘We made a mistake’

While Borschberg set a new record for the solo flight, clocking in at 117 hours and 52 minutes, a chain of events caused the batteries to overheat.

It was only after he landed that the team discovered how bad the damage was.

“We made a mistake with our batteries,” Piccard said after the plane touched down in July. “It was a human mistake.”

And a mistake that took more than nine months to fix.

Back in the air

Solar plane hopes to circumnavigate the globe 01:38 - Source: CNN

Fast forward to this spring, and the Solar Impulse 2 has new batteries, a new cooling system that can be manually operated by the pilot, and $20 million in fresh funding to keep the mission up and running.

The engineers and pilots flew more than eight training and maintenance flights over the past few months, and the plane has been performing remarkably well, Blatt said.

While the team is pumped up and feeling confident, Blatt said he recognizes the challenges ahead, including tricky springtime weather over the U.S. mainland.

After several stops in the United States, the pilots hope to cross the Atlantic Ocean, and then Europe or northern Africa.

They plan to return to the Middle East by late summer, completing a 35,000-kilometer (27,000-mile) trip around the world.

Piccard says he’s been working toward the realization of his dream for 17 years, and “the last 16 years have been more difficult than the flight itself. The flight was for me the accomplishment of this dream … and we can prove the reliability of these clean renewable technologies.”

At least in theory, the plane now has the ability to fly for an unlimited period, Borschberg said, with only the human factor limiting how long the plane could potentially stay on the air.

“When you have the possibility to fly forever, it is an incredible feeling,” he said.