Over a year ago, the solar-powered aeroplane Solar Impulse 2 started its audacious round-the-world trip -- but it became so damaged that it had to pull up short in Hawaii. Now, it's ready to fly again. The aeroplane suffered the set-back during its long flight from Japan to Hawaii -- breaking the record for longest non-stop solo flight, at 117 hours and 52 minutes, in the process. But the takeoff from Japan put too much strain on the batteries that are used to store the solar energy the craft needs to fly.
Now it's all fixed up and tested. New batteries have been fitted and extra cooling systems installed to prevent the problem occurring again in the future. A series of 13 test flights -- including high-altitude testing -- have confirmed it's good to go.
The team is now waiting for a "favourable" weather window in which pilot Bertrand Piccard can set off. Depending on conditions, the aeroplane will head for either Phoenix, San Francisco, Los Angeles or Vancouver. When the Pacific is finally crossed, the rest of the journey remains: On to New York, Europe or North Africa, and then finally Abu Dhabi, where the attempt started.
With 17,000 solar panels on the aeroplane's wing to charge 942kg of lithium battery, Solar Impulse 2 can cruise at a rather slow 142km/h. During the long, continuous flights, pilot Andre Borschberg is only able to take 20-minute naps for breaks. But at least now he's able to fly again.
Image: Solar Impulse