The solar-powered plane that last week made the world's first inter-continental flight by such an aircraft took off Wednesday on its toughest challenge yet -- flying in Morocco's desert climate.
Swiss pilot Andre Borschberg steered the Solar Impulse into the skies from Rabat airport at 0707 GMT and headed south toward the city of Ouarzazate where he is expected to land around 2300 GMT if all goes well.
"This flight will certainly be the most difficult the plane has ever undertaken due to the hot and dry nature of the climate as well as the proximity of the massive Atlas mountains," towering up to more than 3,000 metres (9,800 feet), said a statement released by organisers on Tuesday.
"It is potentially extremely dangerous," said Borschberg. "I know it is not going to be easy but I have the deep feeling that we know enough" to make a successful landing in the desert.
The high-tech aircraft, which has the wingspan of a large airliner but weighs no more than a medium-sized car, is fitted with 12,000 solar cells feeding four electric motors and flies without using a drop of fuel.
Last week it flew into history books as it completed the world's first inter-continental flight by a solar plane, flying from Spain to Morocco, a feat that capped a string of other firsts, including the first manned plane to fly around the clock on the Sun's energy in July 2010.
It also holds the record for the longest flight by a manned solar-powered plane after staying aloft for 26 hours, 10 minutes and 19 seconds above Switzerland, and has also set a record for altitude by flying at 9,235 metres (30,298 feet).
Flying above the Moroccan sand dunes -- the backdrop to the 1962 British cinema epic "Lawrence of Arabia" -- poses particular challenges such as thermal currents, strong winds and thunderstorms.
"At the moment, everything is going very, very well," Borschberg told AFP by satellite phone while the plane was cruising at an average speed of 50 kilometres per hour.
"To avoid air traffic, I am flying above the Atlantic at an altitude of 3,000 metres towards Casablanca," he said.
"After taking off, the plane made a little circuit over Rabat.
"I am then going to follow the south coast towards Marrakech."
Borschberg expects to reach Marrakech, the popular tourist city at the foot of the Atlas range, by the end of the afternoon, flying at an altitude of 6,000 metres.
After rising to its highest altitude above the Atlas, the carbon fibre plane will then "descend as gradually as it can to Ouarzazate," Borschberg said.
"By then, it would be night and the wind is expected to be strong," he said.
"All of that is very exciting and I am looking forward to be in Ouarzazate, close to the site of the new solar power complex which I am planning to visit in the next few days."
Ouarzazate is also the future site of Morocco's first solar energy complex, the solar energy agency Masen said in a joint statement with Solar Impulse.
Last month, the solar-powered aircraft made the 2,500-kilometre (1,550-mile) journey from Madrid to Rabat, its longest to date, after an inaugural flight to Paris and Brussels last year.
The flights are intended as a rehearsal for the goal of a round-the-world trip in 2014 by an updated version of the plane.
The flight is live-streamed on the project's website www.solarimpulse.com.
by Henri Mamarbachi Â© 2012 AFP
Date: Jun 13, 2012