Round two of the Solar Impulse's toughest leg is under way. After the solar plane's first attempt to cross the Pacific was interrupted a month ago, flight engineers spotted what the Japan Times calls a "possible cloudless stretch." That allowed pilot Andre Borschberg to take off from Japan's Nagoya Airfield at 3:04am local time bound for Kalaeloa, Hawaii. The team announced the plane was to depart only an hour before it did so. Borschberg has since "passed the point of no return," meaning he can't return to Japan if he encounters bad weather, according to the project's website, per the BBC. If successful, the leg will be the longest-duration solo flight in aviation history at 120 hours and the furthest distance flown by a strictly-solar aircraft at 4,900 miles.
Prior to starting this leg on a trip around the world, the Impulse 2 had flown about 5,000 miles. Co-pilot Bertrand Piccard is next set to fly the plane from Hawaii to Phoenix before the plane eventually arrives on the eastern seaboard. The Impulse 2 will then attempt an Atlantic crossing, though any further delays could seriously hamper the trip. The team optimally needs to traverse that ocean before the peak of hurricane season in August. The plane had been scheduled to take off from Japan last week, but had to cancel at the last moment due to weather. (Discover how Borschberg will cope during the lengthy Pacific flight.)