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Mission accomplished: Solar Impulse completes 72-hour flight

News International-French

29 Feb 2012

André Borschberg completed the three days and three nights of flight simulation that began in Dübendorf. During those 72 hours the Solar Impulse team was able to test the human challenge posed by long flights and gain valuable insights for the round-the-world solar energy flight scheduled for 2014.

Installed inside a life-size mock-up of the cockpit of the second plane currently under construction, André Borschberg took up the challenge of piloting the Solar Impulse simulator non-stop for 72 hours. Everything was tested and evaluated by the Solar Impulse team, from tiredness to cockpit ergonomics, nutrition, toilets, exercises to prevent DVT, vigilance, and the aptitude to pilot an aircraft under conditions of sleep deprivation.



Emerging from the simulator, André Borschberg, the co-founder, CEO and pilot of Solar Impulse had this to say: “The simulation demonstrated that our concept of flying single-handed for several days in a row is viable. The techniques of relaxation and multi-phase sleep worked very well, exceeding my expectations by far. Thanks to a careful management of the rest periods I was able to maintain optimum vigilance throughout the flight. We learnt a great deal about the practical management of life on board. Going forward, it’s all very positive and taking us ever closer to the round-the-world flight,” he added with a smile.


The EPFL researchers assigned to monitor the pilot’s physiological data were able to roll out solutions on-site that are normally confined to laboratories. In particular, miniature electronics capable of measuring the pilot’s heart and brain functions in real time. The data will be compared with the results of the vigilance and response-time tests and analysed over the coming weeks by physicians of the Hirslanden Group; the data will play a crucial role in defining the pilot’s rest strategy during the round-the-world flight.



During the simulation André Borschberg tested two rest strategies corresponding to the two types of flight the pilots will undertake during the round-the-world trip. Firstly, relaxation techniques used during short flights (24 to 36 hours) over inhabited zones, where sleep is not an option. Secondly, micro-sleep phases of 15 to 20 mins permitted only when overflying oceans. Over the 72-hour period André Borschberg slept 32 times 20 minutes in a seat specially developed by the Swiss company Lantal.



Bertrand Piccard, initiator, chairman and pilot of Solar Impulse, summed up the simulation of the past three days in two words: “STEADY STATE. For a human body, steady state represents the same notion as sustainability when we talk of sustainable development. It means that the physiological parameters have reached a state of equilibrium that allows them to go on working in the same way over a long period.”


The strategy of customised nutrition developed by Nestlé Health Science proved adequate in terms of both taste and nutritional value. The next phase is to develop packaging that is compatible with fluctuations in temperature ranging between -20 °C and +35 °C.


For Solar Impulse this coming spring will have little in common with a simulation. Flights over the Mediterranean region have already been scheduled with the existing prototype. Another means of training for the round-the-world flight by carrying out flights that are longer in both distance and duration, with the two pilots for the first time relaying each other at each stage.

About Solar Impulse
Solar Impulse HB-SIA is the first aircraft that can fly day and night without fuel or polluting emissions. It demonstrates the huge potential of new technologies in terms of energy reduction and the production of renewable energy. This revolutionary carbon fibre aircraft, that has the wingspan of an Airbus A340 (63.4m) and the weight of an average family car (1,600kg), is the result of seven intense years of work, calculations, simulations and tests by a team of 70 people and 80 partners. A plane this light and of this size has never been built before. The 12,000 solar cells built into the wing provide four 10HP electric motors with renewable energy. By day the solar cells recharge the 400kg lithium batteries which means the plane can fly at night.


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