After 13 years of research, design, complex calculations, simulations, construction, testing, training flights, in a field barely explored, Solar Impulse has become the first solar airplane to fly around the world: 40,000 kilometers without a drop of fuel! A real airborne technology lab with endless endurance, capable of crossing oceans and continents by remaining in the air for several days and nights on end. What better way to demonstrate the importance of pioneering spirit than to achieve impossible goals with renewable energy and, by encouraging their use in everyday life, to highlight new solutions for environmental problems?

The vision of a solar airplane flying day and night without using any fuel seemed an obvious next step to Bertrand after his round-the-world balloon flight. Of the 3.7 tons of liquid propane on board at take-off, only 40 kg remained on landing. Success had been entirely dependent on the consumption of the burners. That was the moment when Bertrand promised to himself to go round the world again, but this time taking no fossil fuel with him. In 2002, he asked the Geneva Utilities Department to provide a preliminary analysis, and traveled across the USA to find out how pioneers like Paul McCready and Burt Rutan could help him. Solar airplanes had flown before, but only during the day, and without any capacity for storing energy.

«Solar Impulse has flown more than 40,000 kilometers without fuel, but with an inexhaustible supply of energy and inspiration. This is a historic day for Captain Piccard and the Solar Impulse team, but it is also a historic day for humanity. You may be ending your around the world flight today, but the journey to a more sustainable world is just beginning. The Solar Impulse team is helping to pilot us to that future.»

Ban Ki-moon, UN Secretary-General

«If the round-the-world balloon flight was the final adventure of the 20th Century, Solar Impulse is without doubt the first to encapsulate the challenges of the 21st.»

Albert de Monaco

«Solar Impulse was not built to carry passengers, but to carry a message about the use of clean technologies. More than a plane, I want Solar Impulse to be a powerful demonstration of the potential of modern clean technologies. An airplane with unlimited endurance, flying day and night without fuel, should motivate people to implement solutions solving climate change and pollution issues around the world.»

Bertrand Piccard

In 2003, the Swiss Federal Institute of Technology in Lausanne became enthusiastic about the idea and offered to conduct a feasibility study. This task was allocated to André Borschberg. A friendship was born, and a determination to work together to ensure successful execution of the project. André, an entrepreneur, engineer and professional pilot, put together the technical team and directed the building of the prototype. Bertrand, the visionary and communicator, developed the forward-looking philosophy of the project, outlining its symbolic and political significance in a way that convinced financial partners to back the challenge.
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By placing dreams and emotions at the center of scientific adventure, Bertrand and André are trying to point out the paradigm shifts that can be achieved immediately and will improve the state of the world. Not just by using technology, but equally importantly through responsible citizenship. To be part of the Solar Impulse adventure is to subscribe to an initiative that shows why surpassing personal limits makes sense, and places human-oriented values back at the center of debate.

«It’s easy to generate public enthusiasm for great adventures – people are keen to share the dreams of pioneers and explorers. A solar airplane that can fly day and night and even round the world without any fuel conveys a strong message. If it is possible to get by without fossil fuels in the air, nobody can ever again claim that we cannot do it in our daily lives on the ground, in our cars, houses, heating systems, air conditioners and electric lights. We need to generate positive feelings about renewable energies and clean technologies that allow energy to be saved. Let’s draw governments’ attention to the unavoidable changes that are needed to secure the planet’s future energy supplies and ecological balance. Let’s show how environmental protection can be profitable and stimulating for us. Let’s show how alternative energy sources, allied to new technologies, can help us achieve things previously considered impossible.» »

Bertrand Piccard

THE ZERO-FUEL AIRPLANE
Solar Impulse 2: the wingspan of an Airbus 340, but the weight of a car ! In order to fly by day and by night using only solar energy, Solar Impulse has to reach absolutely unprecedented levels of aerodynamic performance and energy efficiency. This requirement led the whole team, under the direction of André Borschberg, to bring off an amazing technological feat - building a carbon-fiber airplane with a span of 64 meters that weighs only 1,600 kg ! No aircraft manufacturer had thought it possible to meet such a challenge. They had to work with no benchmarks to rely on, using ultralight materials and new manufacturing processes, at the very boundary of the possible. The lithium batteries, which weigh 600 kg, are recharged during the day by 270 m2 of photovoltaic cells, allowing flight to continue through the night before a new cycle starts the following morning. The price to be paid for this is a very low speed (on average 70 km/h) and high sensitivity to turbulence. Only one pilot can be carried. So Bertrand and André take turns in the cockpit. The pilots' endurance was tested during the longest Round-the-World flights over the Atlantic and Pacific Oceans that lasted between three to five days.

«Just imagine your energy reserves increasing during flight! To make this dream a reality, we had to make maximum use of every possible source of energy efficiency. By tapping into each team member’s experience and using the combined potential of them all, we managed to find the solutions.»

André Borschberg

«By circumnavigating our planet, Solar Impulse achieved its aim: to promote renewable forms of energy and clean technologies capable of reducing society’s dependence on fossil fuels. The solar airplane attracts the highest political and economic authorities into debates on the technological solutions currently available to achieve internationally agreed CO2 reduction targets. Each such encounter is also an opportunity to raise the problems of resistance to change and the dangerous or costly effects of using old technologies.»

Bertrand Piccard

«My vision of the future is not a ‘green’ vision but a ‘clean’ vision. All too often, ‘ecology’ is threatening our life style, which is not exactly motivating. People don’t want less, they want better. It will be easier to protect the environment with a broader use of modern clean technologies, than by fighting against societal trends in mobility, comfort and growth. That is the way forward, the way to the future, and Solar Impulse is the ambassador of this vision.” »

Bertrand Piccard