The world’s largest solar-powered aircraft, Solar Impulse 2, was forced to push back the second half of it’s round-the-world flight to early spring 2016 due to irreversible damage to overheated batteries, the team behind the project announced Wednesday. Following a record-breaking oceanic flight of five days and five nights (117 hours and 52 minutes) from Nagoya to Hawaii, the aircraft, equipped with as many as 17,000 solar cells, suffered battery damage due to overheating. The team said the battery temperature increased too much due to over insulation of the gondolas and there was no way to decrease the temperature for the remaining duration of the flight. Irreversible damage to certain parts of the batteries require repairs which will last several months. In parallel, the team will study various options for better cooling and heating processes for very long flights.