Solar Impulse completes historic round-the-world trip

The Solar Impulse has become the first aircraft to circle the globe powered by the sun, after landing in Abu Dhabi on the last leg of its journey.

Bertrand Piccard piloted the plane for a final time, steering it safely from the Egyptian capital Cairo to the UAE.

Throughout the voyage Piccard took turns at the controls with Swiss compatriot Andre Borschberg.

The final leg brought to an end a 17-leg voyage that began in Abu Dhabi on 9 March last year, spanning across four continents, three seas and two oceans.

The longest leg, a 8,924km flight from Nagoya in Japan to Hawaii, US, lasted nearly 118 hours and saw Borschberg break the world record for longest uninterrupted solo flight.

Piccard and Borschberg have been working on the Solar Impulse project for more than a decade.

According to the BBC, Solar Impulse is comparable to a car in weight, but has the wingspan of a Boeing 747. It is powered by 17,000 solar cells but the experimental design is said to present a number of technical challenges, with the airplane very sensitive to weather conditions.

The cockpit is reportedly about the size of a public telephone box, with the pilots having to wear oxygen tanks to breathe at high altitude and permitted to only sleep for 20 minutes at a time.