Switzerland in an amazing feat of aeronautical engineering developed a long range environmentally friendly solar powered aircraft. Solar Impulse is a Swiss long-range solar-powered aircraft project. It is led by Swiss psychiatrist and aeronaut Bertrand Piccard, who co-piloted the first balloon to circle the world non-stop, and Swiss businessman André Borschberg. The privately-financed project hopes to achieve the first circumnavigation of the Earth by a piloted fixed-wing aircraft using only solar power.
The first aircraft, bearing Swiss aircraft registration HB-SIA and often referred to as Solar Impulse 1, is a single-seat monoplane, capable of taking off under its own power, and designed to be able to remain airborne up to 36 hours. This aircraft conducted its first test flight in December 2009, and first flew an entire diurnal solar cycle, including nearly nine hours of night flying, in a 26-hour flight on 7–8 July 2010. Piccard and Borschberg completed successful solar-powered flights from Switzerland to Spain and Morocco in 2012, and conducted a multi-stage flight across the USA in 2013.
Building on the experience of this prototype, a slightly larger follow-on design, HB-SIB, known as Solar Impulse 2, was built and first flown in 2014. It is planned to make a circumnavigation of the globe over the course of about five months during 2015. This flight was initially planned for 2014, but following a structural failure of the aircraft’s main spar during static testing in 2012, the flight was rescheduled for 2015. The circumnavigation is scheduled to begin in March 2015 in Abu Dhabi in the United Arab Emirates and to return there five months later. The legs of the flight crossing the Pacific and Atlantic oceans are expected to take between five and six days.
Role Experimental solar-powered aircraft
National origin Swiss
Manufacturer Solar Impulse
Designer Solar Impulse
First flight 3 December 2009
Number built 2 (including prototype)
Length: 22.4 m (73.5 ft)
Wingspan: 71.9 m (236 ft)
Height: 6.37 m (20.9 m)
Wing area: 17,248 photovoltaic cells (269.5 m2)
Loaded weight: 2,300 kg (5,100 lb)
Powerplant: 4 × electric motors, 4 lithium-ion batteries (633 kg), providing 13 kW (17.4 HP) each
Propeller diameter: 4 m (13.1 ft)
Take-off speed: 35 kilometres per hour (22 mph)
Maximum speed: 77 kts (140 km/h) 49 kts
Cruise speed: 90 km/h
Service ceiling: 8,500 m (27,900 ft) with a maximum altitude of 12,000 metres (39,000 ft)
Design and development
Piccard initiated the Solar Impulse project in November 2003 after undertaking a feasibility study in partnership with the Ecole Polytechnique Fédérale de Lausanne. By 2009 he had assembled a multi-disciplinary team of 50 engineers and technical specialists from six countries, assisted by about 100 outside advisers and 80 technological partners. The project is financed by a number of private companies and individuals. The first company to officially support the project was Semper Gestion, after co-founder Eric Freymond was convinced of the future success of the highly media-friendly Bertrand Piccard. At present the main partners are Omega SA, Solvay, Schindler and ABB. Other partners and supporters of the project include Bayer MaterialScience, Altran, Swisscom, Swiss Re (Corporate Solutions), Clarins, Toyota, BKW FMB Energie and Symphony Technology Group. The EPFL, the European Space Agency (ESA) and Dassault have provided additional technical expertise, while SunPower provided the aircraft’s photovoltaic cells. In October 2013, Solar Impulse announced that Peter Diamandis had committed to supporting the project after meeting with Solar Impulse officials during that year’s Google Zeitgeist.
2003: Feasibility study at the École Polytechnique Fédérale de Lausanne
2004–2005: Development of the concept
2006: Simulation of long-haul flights
2006–09: Construction of first prototype (HB-SIA; Solar Impulse 1)
2009: First flight of Solar Impulse 1
2009–11: Manned test flights, including first all-night flight in 2010.
2011–12: Further test flights through Europe and North Africa in 7 legs
2011–13: Construction of second prototype (HB-SIB; Solar Impulse 2)
2013: Continental flight across the US of Solar Impulse 1 (Mission Across America)
2014: First flight of Solar Impulse 2
2015: Planned world tour of Solar Impulse 2, in several stages over five months, expected to begin in March
HB-SIB (Solar Impulse 2)
Construction of the second Solar Impulse aircraft, carrying the Swiss registration HB-SIB, started in 2011. Completion was initially planned for 2013, with a 25-day circumnavigation of the globe planned for 2014.