Solar plane circles globe for first time

The first round-the-world solar powered flight has been completed, after the Solar Impulse aircraft touched down in Abu Dhabi.

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

He has been taking turns at the controls with Swiss compatriot Andre Borschberg, with the mission aiming to promote renewable energy.

Clean energy for future

It brings to an end a voyage that began in Abu Dhabi on 9 March last year.

"The future is clean. The future is you. The future is now. Let's take it further,'' Piccard said, arriving into Abu Dhabi to cheers and applause.

The 17-stage journey took in four continents, three seas and two oceans.

The longest leg, an 8,924km (5,545-mile) 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.

The pair had hoped to complete the challenge last year but progress was not quite swift enough to get the best of the weather in the Northern Hemisphere's summer.

Solar Impulse is no heavier than a car, but has the wingspan of a Boeing 747. It is powered by 17,000 solar cells.

But the experimental design presents a number of technical challenges, with the airplane very sensitive to weather conditions.

Indeed, the passage from Cairo was very bumpy for  Piccard as he battled severe turbulence above the hot Saudi desert.

The cockpit is 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.

LEG 1: 9 March. Abu Dhabi (UAE) to Muscat (Oman) - 772km; 13 Hours 1 Minute

LEG 2: 10 March. Muscat (Oman) to Ahmedabad (India) - 1,593km; 15 Hours 20 Minutes

LEG 3: 18 March. Ahmedabad (India) to Varanasi (India) - 1,170km; 13 Hours 15 Minutes

LEG 4: 18 March. Varanasi (India) to Mandalay (Myanmar) - 1,536km; 13 Hours 29 Minutes

LEG 5: 29 March. Mandalay (Myanmar) to Chongqing (China) - 1,636km; 20 Hours 29 Minutes

LEG 6: 21 April. Chongqing (China) to Nanjing (China) - 1,384km; 17 Hours 22 Minutes

LEG 7: 30 May. Nanjing (China) to Nagoya (Japan) - 2,942km; 1 Day 20 Hours 9 Minutes

LEG 8: 28 June. Nagoya (Japan) to Kalaeloa, Hawaii (US) - 8,924km; 4 Days 21 Hours 52 Minutes

LEG 9: 21 April. Kalaeloa, Hawaii (US) to Mountain View, California (US) - 4,523km; 2 Days 17 Hours 29 Minutes

LEG 10: 2 May. Mountain View, California (US) to Phoenix, Arizona (US) - 1,199km; 15 Hours 52 Minutes

LEG 11: 12 May. Phoenix, Arizona (US) to Tulsa, Oklahoma (US) - 1,570 km; 18 Hours 10 Minutes

LEG 12: 21 May. Tulsa, Oklahoma (US) to Dayton, Ohio (US) - 1,113 km; 16 Hours 34 Minutes

LEG 13: 25 May. Dayton, Ohio (US) to Lehigh Valley, Pennsylvania (US) - 1,044 km; 16 Hours 47 Minutes

LEG 14: 11 June. Lehigh Valley, Pennsylvania (US) to New York (US) - 230km; 4 Hours 41 Minutes

LEG 15: 20 June. New York (US) to Seville (Spain) - 6,765km; 2 Days 23 Hours 8 minutes

LEG 16: 11 July. Seville (Spain) to Egypt (Cairo) - 3,745km; 2 Days 50 Minutes

LEG 17: 23 July. Egypt (Cairo) to Abu Dhabi (UAE) - 2,694 km; 2 Days 47 Minutes