Solar Impulse's troubled round-the-world flight: ‘We need to raise €20m'

The solar plane's attempt to fly around the world has been grounded by battery failure. As the pilots regroup for the next leg, they discuss the highs and lows of their epic journey

The darkest moment of Andri(C) Borschberg's unprecedented solar flight across the Pacific was not when he learned of the battery failure that has now suspended the Solar Impulse flight until next spring.

It was 12 hours into the journey, as he flew about 6,000 metres over the Pacific, south-east of Tokyo, and a decision had to be made about whether to continue. "Before every flight you have what we call the point of no return - it was the afternoon of the first day," he says.