A new hope for Solar Powered vehicles: Zero Fuel Solar Airplane that flies at night!


There seems to be a refreshing new hope for all of us interested in entering a new era of efficient, renewable, and non-contaminating energies. For some of us, Solar Power stands as the best candidate.

This new hope is brought by SOLAR IMPULSE, a project founded by Bertrand Piccard, psychiatrist and aeronaut and André Borschberg, an engineer and graduate in management science. For seven years, a team of 50 engineers and technicians have been working on the HB-SIA solar aircraft, zero fuel and completely solar-powered aircraft that is able to fly at night.

Solar Powered vehicles have been in development since the 1980’s. For a long time, there were no really satisfying results. Even today when you mention solar-powered vehicles people tend to imagine a really bulky thing that moves very slow and just stops if the sky gets cloudy – just a scientific curiosity that has no practical use.

However, the SOLAR IMPULSE team is changing the scenario.


SOLAR IMPULSE is a partnership between several companies (Solvay, Omega, and Deutsche Bank among others) that expresses a positive vision of scientific adventure, environmental awareness, and contribution to future generations.

This brings some hope for the world that is currently based on squeezing up earth’s natural resources until the last drop to derive economic benefits from a reduced number of people, and not considering future or present consequences in the account.

There is certainly necessity of abandoning the ‘resource-exhausting economy’ simply because it won’t be possible to continue with it much longer. In the words of SOLAR IMPULSE founder, Bertrand Piccard:

“Adventure is not necessarily a spectacular deed, but rather an “extra-ordinary” one, meaning something that pushes us outside our normal way of thinking and behaving. Something that forces us to leave the protective shell of our certainties, within which we act and react automatically. Adventure is a state of mind in the face of the unknown, a way of conceiving our existence as an experimental field, in which we have to develop our inner resources, climb up the path of our personal evolution and assimilate the ethical and moral values, which we need as our travel companions.”

HB-SIA Solar Powered Aircraft

From the beginning of the project, the intention was to produce a completely self-sufficient solar-powered aircraft that could sustain flight on both day and night and come close to perpetual flight. This is a tremendous challenge. Even with the advent of PV, which has made them more efficient, the balance between precise aerodynamics and dimensions required by the solar panels array to produce the necessary energy is difficult to achieve.  Also, materials have to be very lightweight yet very resistant.

HB-SIA prototype has a 63.40 meters wingspan – almost exactly the same as the giant Airbus A340-500- and has the weight of an average car at 1600 kg. Making an aircraft with those characteristics is something new in the aeronautics world. In order to achieve the target, the airplane structure was constructed with carbon fibre-honeycomb composite. The solar panels are encapsulated and placed on the upper side of the wings, while the bottom is covered with high resistance flexible film.

The Aircraft is able to sustain night fly because it stores the solar-powered energy on lithium polymer batteries.  It can be a problematic issue to improve as the energy storage systems weights 400kg – one-fourth of the overall weight- and it is not really efficient.


Wingspan 63.40 m
Length 21.85 m
Height 6.40 m
Motor power 4 x 10 HP electric engines
Solar cells 11,628 (10,748 on the wing, 880 on the horizontal stabilizer)
Average flying speed 70 km/h
Maximum altitude 8,500 m (27,900 ft)
Weight 1,600 kg
Take-off speed 35 km/h


On 7 April 2010, the prototype made a successful maiden flight.
As reported by SOLAR IMPULSE, on 7 July 2010 at 06:51, the HB-SIA took off from the Swiss Payerne airbase with André Borscherg, CEO and co-founder, at the controls. This time the intention is to perform a full night flight.

As this article is being written the aircraft has already fully charged the batteries and has entered in shadows of the night. We will update to inform about the outcome of the mission, that we are confident it will be successful.


  • The plane was up in the air yesterday for the whole day, then through the entire night, flying solely on solar energy. This flight is the longest and highest in the history of solar aviation! FLIGHT REPORT
  • Pilot: André Borschberg, CEO and Co-founder
  • Take-off time: 07/07/2010 – 06h51
  • Landing time: 08/07/2010 – 09:00\
  • Flight duration: 26 hours 09 min
  • Maximum speed: 68 knots (ground speed)
  • Average speed: 23 knots
  • Maximum altitude: 8564 m (above sea-level)
  • Our congratulations to the Solar Impulse team for making good & clean history!

HB-SIA OFFICIAL BROCHURE: http://www.solarimpulse.com/pdf/hb-sia/hb-sia_en.pdf

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