A solar plane on an around-the-world journey has reached the point of no return over the Pacific Ocean after departing Hawaii, and now it's California or bust, the AP reports. The plane was cruising over the cold northern Pacific late Thursday at about 20,000 feet with a nearly-full battery as night descended, according to the website that's documenting the journey of Solar Impulse 2. The plane is on course to land in Mountain View, Calif., in about three days. Pilot Bertrand Piccard, who is flying this leg of the journey accompanied by co-pilot Andre Borschberg, said Thursday he's confident things will go according to plan, adding the destination in the heart of Silicon Valley is fitting as the plane will land "in the middle of the pioneering spirit."
At one point the plane was passed by a Hawaiian Air jet whose passengers caught a glimpse of the Solar Impulse 2. The solar aircraft landed in Hawaii in July and was forced to stay after the plane's battery system sustained heat damage on its trip from Japan. The aircraft started its journey in March 2015 from the United Arab Emirates and made stops in Oman, Burma, China, and Japan. It's on the ninth leg of its circumnavigation. The trans-Pacific leg is the riskiest part of the plane's global travels due to the lack of emergency landing sites. The plane's ideal flight speed is about 28mph, though that can double when the sun's rays are strongest. The carbon-fiber aircraft weighs about as much as a midsize truck; its wings, which stretch wider than those of a Boeing 747, are equipped with 17,000 solar cells that power propellers and charge batteries. (Read more Solar Impulse stories.)