The Solar Impulse 2, which is halfway through an attempt to circle the globe, has been grounded in Hawaii for at least nine months because of battery damage sustained during its record 118-hour trans-Pacific flight from Japan, the project team said on 15 July.

The aircraft is not expected to take off on the next leg of its journey - a four-day, four-night flight to Phoenix, Arizona - until late April or early May 2016, the team said.

Additional time is needed to repair the plane's four batteries, which store energy from the sun during daylight hours to keep the aircraft powered overnight, allowing it to remain aloft around the clock on extreme long-distance flights.

The batteries became overheated during the plane's initial ascent after take off on 29 June from Nagoya, Japan, en route to Hawaii on the seventh and most challenging leg of its circumnavigation attempt.

The team stressed in a press statement that the damage was "not a technical failure or weakness in the technology." Instead, the team had miscalculated the extent of the temperature increases and amount of insulation that would be needed for the tropical climate they encountered on the ascent from Nagoya.

Still, flight controllers and the pilot managed to successfully complete the Japan-to-Hawaii leg, safely landing in Honolulu on 3 July after 117 hours and 52 minutes aloft.

The trip shattered the 76-hour record for a nonstop solo flight set in 2006 by the late American adventurer Steve Fossett in the Virgin Atlantic Global Flyer.

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