Solar Impulse begins penultimate leg of round-the-world flight

The solar-powered aircraft Solar Impulse embarked this morning upon the penultimate leg of its historic round-the-world flight, leaving Seville in southern Spain at 0420 GMT on the way to Cairo in Egypt.

In a journey that is expected to take 50 hours and 30 minutes, Andre Borschberg will take the controls for what is the 16th leg of the trip, piloting the Si2 aircraft over the Mediterranean towards Tunisia, over Algeria, Malta, Italian and Greek airspace, before touching down – all being well – in Cairo later this week.

The solar aircraft has more than 17,000 solar cells fitted across its wings and fuselage, and has made it nearly all the way around the world using only the power of the sun for energy. There are four large lithium-ion batteries on board and four electric motors, which propel the plane to a top speed of 70 km per hour (43 mph).

The journey began in March in 2015, when the Si2 took off from Abu Dhabi and headed east. After a grueling leg from Japan to Hawaii, the pilots – Borschberg and Betrand Piccard – alongside the ground crew identified some "irreversible battery damage" that required urgent attention upon arrival in Hawaii.

This delay meant that the Solar Impulse team missed its window of opportunity to continue on its journey, delaying the remaining legs of the flight by a few months. However, the overall aim – to get around the globe using no fossil fuels – remains in sight, with the Si2 already having broken a string of records, including the longest-ever solo flight and the first solar-powered aircraft to successfully cross the Atlantic Ocean.

"This flight across Europe will touch a large number of countries, very diverse in terms of culture, climate and geography. But in addition to all being on the shore of the Mediterranean Sea, they have a common denominator: the potential benefit of using renewable energies and clean technology,” said Borschberg, Co-founder and CEO currently at the controls of the solar airplane.

"After 36’000 km, people might start to find it obvious to fly day and night without fuel, but it’s still a very difficult endeavor and the challenge will remain open until the last minute," added Piccard, Initiator, Chairman and pilot.