Solar plane's first international flight a success

Solar plane's first international flight a success
Solar Impulse has successfully completed its first international flight (Solar Impulse during flight tests earlier this year / Image: Solar Impulse)
Solar Impulse has successfully completed its first international flight (Solar Impulse during flight tests earlier this year / Image: Solar Impulse)
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Solar Impulse has successfully completed its first international flight (Solar Impulse during flight tests earlier this year / Image: Solar Impulse)
Solar Impulse has successfully completed its first international flight (Solar Impulse during flight tests earlier this year / Image: Solar Impulse)

Solar Impulse has successfully completed its first international flight. After spending most of last week on standby waiting for favorable weather conditions, the Swiss solar powered aircraft made the run from Payerne to Brussels on Friday May 13 in a flight that lasted 12 hours 59 minutes. Hats-off to the Solar Impulse team!

Solar Impulse is an astonishing feat of engineering. It has a wingspan of over 200 feet (61 m) yet it weighs only 1600 kg (3,527 lb) and carries almost 12,000 solar cells which supply all of the energy required to keep it aloft.

The plane has actually flown for a longer duration than Friday's 12 hours 59 minute flight, setting a mark of more than 26 hours in an overnight flight last summer. The achievement of its first international flight is as much about the logistics of civil aviation as it is about performance. Solar Impulse is a slow moving aircraft – during the latest flight it flew at around 31 mph (50 km/h) – and this makes for some unique challenges when it comes to flight planning as Solar Impulse Air Traffic Control manager Niklaus Gerber explains on the Solar Impulse Blog:

"HB-SIA is an obstacle for civil and military aviation because it is not very mobile, and rather inflexible. It is slow (31 mph/50 km/h) and does not really show up on radar (you see it as a point that hardly moves). Now, alongside it, there are aircraft that are traveling at between 400 and 900 km/h. So the other aircraft are the ones that have to make adjustments to avoid it. But this scenario is theoretical because we have done everything to avoid it in planning the flight. Usually, the separation distance between aircraft is 300 meters (984 ft) vertically and 8 kilometers (5 miles) when flying at the same height. In the case of Solar Impulse, our margin of safety is much greater. And an aircraft that passes above it needs to be at least 900 meters (2,953 ft) higher, due to the turbulence it creates which descends for about 5 minutes at a rate of 150 meters (492 ft) per minute before dissipating."

Successfully negotiating these constraints in the flight from Switzerland to Belgium is therefore a big milestone in the build up towards the planned round-the-world journey.

A new future for aviation?

The project founded by Bertrand Piccard and André Borschberg (who was at the controls during the first international flight) is not geared towards producing a commercial product but instead aims to demonstrate just how much can be achieved with renewable technology. Even without the round the world trip that the team plans to undertake in 2013, it's arguable that the achievements of the past year which began with the aircraft's maiden flight in April 2010 have already gone a long way to proving the point. We could well be looking back on this period as a "Wright brothers moment" in the history of aviation.In the flight from Payerne to Brussels, Solar Impulse covered around 390 miles (628 km) using no fuel. A rough calculation tells us that a Boeing 747 would have used around 2,000 gallons (7,570 L) of fuel to make the same trip.* Of course it's not much of a comparison when you consider that a commercial airliner can carry hundreds of people, but one can't help but think that the seeds of a new era are being sewn. Solar Impulse is powered by 4 x 10 horsepower electric engines, the Wright brothers had 12 horsepower at their disposal when they flew at Kitty Hawk in 1903. Food for thought.

Watch the majestic landing at Brussels in the Solar Impulse video below:

* A 747-400 that flies 3,500 statute miles (5,630 km) and carries 126,000 pounds (56,700 kg) of fuel will consume an average of five gallons (19 L) per mile (

Brussels Airport Landing - Solar Impulse 1

Alberto Rezende Almeida
hope this future comes quikly . thank you cientists for all the developments in this
I was excited about the Solar Impulse until I learned about how fragile it is ( I deduce this from the article\'s contents ) . What good is an aircraft that must wait for favourable weather conditions and can be destroyed by turbulence from a passing plane ? A useful aircraft flies in nearly any kind of weather and can survive near misses by other aircraft ( 50 meters ).
Bill Clohessy
I don\'t see the airline offering seats to consumers anywhere in this article, I don\'t see any claims that this is the final product offering. What I do see is what is called a starting point and a very positive one at that. Hopefully they can continue to build incrementally on this launching pad so that further down the track we do have a commercially viable and environmentally-sustinable option for air travel that includes the utilities you mention.
The first heavier than air (i.e. conventional) airplanes were about as fragile as this one is. What would have happened if they´d said then ´aw what the hell, there can´t be any serious use for this sort of thing´. Yup, you guessed it. It takes vision and perseverance to achieve a goal.
Yes, good thing the Wright Brothers didn\'t have the defeatist attitude displayed by gusPuppet. No one expected some miracle in solar-powered flight overnight, but this definitely marks a strong beginning. Solar cells continue to improve at a rapid pace, such that within a decade the cells will probably be able to generate twice the amount of power but with only 1/3rd of the surface area. There are also ongoing improvements in the energy density of batteries, meaning that, in a decade, we\'ll probably see batteries with twice the storage capacity, but at barely 1/3rd the weight. I will also add the following prediction-in 30 years time we\'ll see solar powered *jet* aircraft-aircraft that use photovoltaics to break water (or some other hydrogen containing compound) down into hydrogen-then burning the hydrogen to produce jet power. Better still, the aircraft could do minor refueling in mid-air, by collecting & splitting water vapor as they go.
Bill Bennett
Alberto, Bill and bas thank you for the intelligent comments, umm gus,, well never mind
I see....... if someone has an opposing view from yours.... they are not intelligent...ah so ..... ad homenims away ! .......... Willing to make a bet about where the Solar Impulse ends up ? I know let\'s harness zero point energy and then build a clubhouse. Sorry could not resist ( my bad ) 99guspuppet
Isaac Piquiel Filani
another word for surprises is technology.