Solar Impulse is the name of a Swiss long-range experimental solar-powered aircraft project, and also the name of the project's two operational aircraft. The privately-financed project is led by Swiss businessman André Borschberg and Swiss psychiatrist and aeronaut Bertrand Piccard, who co-piloted the first balloon to circle the world non-stop. The Solar Impulse project intends to achieve the first circumnavigation of the Earth by a piloted fixed-wing aircraft using only solar power.
The prototype aircraft, bearing the Swiss aircraft registration code HB-SIA and often referred to as Solar Impulse 1, is a single-seat monoplane powered by photovoltaic cells and capable of taking off under its own power. It is designed to remain airborne up to 36 hours. The aircraft conducted its first test flight in December 2009. In July 2010, it flew an entire diurnal solar cycle, including nearly nine hours of night flying, in a 26-hour flight.Piccard and Borschberg completed successful solar-powered flights from Switzerland to Spain and then Morocco in 2012, and conducted a multi-stage flight across the United States in 2013.
Improving on the prototype, a slightly larger design was created in 2014, designated HB-SIB and named Solar Impulse 2. In March 2015, Piccard and Borschberg began a circumnavigation of the globe with Solar Impulse 2, departing from Abu Dhabi in the United Arab Emirates. The aircraft is scheduled to return to Abu Dhabi in August 2015.
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
2011–12: Further test flights through Europe and North Africa
2011–13: Construction of second prototype (HB-SIB; Solar Impulse 2)
2013: Continental flight across the US by Solar Impulse 1 (Mission Across America)
2014: First flight of Solar Impulse 2
2015: Circumnavigation by Solar Impulse 2, conducted in twelve stages over five months
The Solar Impulse project in numbers:
12 years of feasibility study, concept, design and construction
50 engineers and technicians
80 technological partners
more than 100 advisers and suppliers
1 prototype (Solar Impulse 1, registered as HB-SIA)
1 final airplane
(Solar Impulse 2, registered as HB-SIB)
The wingspan of HB-SIB is 71.9 m (236 ft), slightly less than that of an Airbus A380, the world's largest passenger airliner, but unlike the 500-ton A380, the carbon-fibre Solar Impulse weighs only 2.3 tonnes (5,100 lb), little more than an average automobile. It features a larger, non-pressurized cockpit and advanced avionics, including an autopilot to allow for multi-day transcontinental and trans-oceanic flights. Supplemental oxygen and various other environmental support systems allow the pilot to cruise at an altitude of 12,000 metres (39,000 ft).