Special report: Plane talking

In 2003, adventurer Bertrand Piccard took his dream of building a unique aircraft to André Borschberg, an engineer and pilot, and the Solar Impulse project was born. ICIS asked them about their dream, the hurdles they overcame and what the future holds

What was behind your vision for building a solar aircraft?

Bertrand Piccard (BP): Our message highlights the importance of a pioneering and innovative spirit, especially in the domain of clean technologies. Nowadays, the technological solutions that allow Solar Impulse to fly both day and night are accessible to all and are replicable in everyday life. These are not secret, futuristic technologies. If they were used routinely in our society, we would be able to save 50% of our consumption of fossil energies and to produce half of the rest with renewable energies. Solar Impulse wants to emphasize the energy solutions as well as the environmental and political solutions from a decidedly constructive angle in order to engender enthusiasm and the necessary motivation to leave behind this pervading fatalism. Aviation makes you dream, feeds your passions. A plane that flies without fuel and achieves something everyone imagined impossible will fire our imaginations and encourage many people to invest in the practical solutions that our society needs.

How has support from the chemical industry made this challenge possible?

Solar Impulse | Righetti | Rezo.ch André Borschberg (left) and Bertrand Piccard are ready to make history

André Borschberg (AB): The interesting thing with Solar Impulse is that most of the partners don’t come from the aviation industry. In fact only a few of the 80 partners are active in this field. All the innovative solutions come from other industries, especially the chemical one. They push the boundaries out of their comfort zone and came up with solutions to meet the very specific requirements of Solar Impulse: build an airplane with the wingspan of a jumbo jet and the weight of a car capable of flying day and night on solar energy only.

What were the most significant contributions from both Solvay and Bayer MaterialScience and how has their experience helped?

AB: The solutions developed by Solvay and Bayer MaterialScience for the airplane are key in multiple areas such as ultralight materials and energy savings, efficiency of components, and solar cells and in the energy storage through increase of energy density of the batteries. Solvay has 13 products on Solar Impulse 2 which enhanced its performance while keeping its weight to a minimum. These products have accessed a host of promising new markets, including solar panel protection, computer and mobile phone batteries, baggage compartments on planes and sustainable solutions in mobility. Bayer MaterialScience developed among other products the insulation foam. This new foam has very thin pores, high rigidity and structural strength while remaining very light. It allows us to do without a cooling or heating system for the batteries and in the cockpit. It is also used in the best refrigerators and in the construction sector.

What were the greatest technical challenges you faced during the project – and how were they overcome?

AB: On 5 July 2012, we were on the verge of rejoicing for an accomplished mission until, unexpectedly, Solar Impulse 2’s wing spar cracked and the final structural test failed. Pushing the limits is no easy task and the failing of the spar led to a partial rebuilding of it, consequently causing a construction delay. It was the first time a final structural test had failed in the history of the project and even though it was hard to accept, it’s an extremely valuable learning experience. What has emerged from this situation is that the flight around the world, scheduled for 2014, was an extremely ambitious deadline and that 2015 was more realistic. Moreover, it has made room for some stimulating brainstorming sessions within the team not only on how to use the time gained to improve the reliability of the aircraft but also to further emphasize the project’s message and value.

After next year’s flight around the world, what next for the Solar Impulse project?

BP: For the time being our focus is to complete the first round-the-world solar flight in stages. As long as we have not succeeded it will be considered as impossible. Let’s start here and afterwards think of the next step. To bring such an endeavour to success you have to keep full focus on it.