Solar Impulse is a display of clean technologies, a genuine Flying Laboratory.

1. FLYING LABORATORY
Solar Impulse’s attempt to fly around the world powered only by solar energy set a goal many thought
“impossible” and placed the bar very high. A family group of partners took up the challenge to invent
new paradigms and find the answers to problems that until now had remained unsolvable. They
combined their very diverse backgrounds and specialist talents to build bridges between various areas
of expertise and push back the frontiers of technological knowledge. These solutions are found in all
the plane’s systems from the structure to the pilot equipment, they made the airplane become a weapon
to demonstrate what can be achieved with pioneering spirit and clean technologies.
HIGHLIGHTS
STRUCTURE Carbon fiber sheets only 25 g / m² (0.8 oz. /11 sq ft.)
– 3 times lighter than paper
SOLAR CELLS Only 135 microns thick – like an average human hair
MOTORS 3% energy loss versus 70% in normal thermal motors
BATTERIES High energy density – 260 Wh /kg (348 hp)
COCKPIT Isolation foam with very thin pores to insulate from
extreme temperatures during flights
MAN-MACHINE INTERFACE Informing the pilot of the aircraft’s bank
angle through a vibration device
LIGHTING 16 LED landing lights consuming less than 2 bedside
lamp-bulbs
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2. FUSELAGE
Solar Impulse engineers developed a winded fiber design to achieve the lowest possible weight and
incredible strength.
Especially light composite
materials used for
competitive yachting
Manufactured by Decision
A new technology that is currently being adapted to the construction of high
performance yachts. Eighty-three percent of Si2’s structure is made out of extremely
light composite materials. A new thin ply technology has been used and the gluing
process optimized.
First time carbon fiber
composites can be mass
produced
Brought to you by Covestro
A crucial innovation that has allowed mass production of carbon fiber composites and
further weight reduction of carbon fiber components. This could be the answer for size
limitations such as for rotor blades for the wind industry or for cycle-time issues in
the automotive industry. At Solar Impulse, carbon fiber components are used in the
cockpit fairing providing mechanical strength in applications which would usually
require epoxy. This technology was already exploited commercially as a conductive
material in electrodes.
Ultra-light thin ply
technology
Solution brought by EPFL
and North TPT
Thanks to the new thin ply technology developed by the Swiss company North TPT, the
solar airplane is built with carbon sandwich instead of epoxy-enhanced solid carbon.
This technology has reduced the weight of some layer of carbon material from
100 grams per m² (3.5 oz. /11 sq ft.) to 25 g/m2
(0.8 oz. /11 sq ft.).
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3. WINGS
One hundred forty-four ribs carefully placed at 50 cm (20 in.) intervals by Solar Impulse engineers.
The upper surface of the wings is made of solar panels and the lower part with an ultra-light fabric.
The wing spar is entirely made of carbon fiber honeycomb sandwich panels.
Thin, UV resistant,
waterproof resin
Conceived by Solvay
Thin fluorine copolymer film with a potential use for electric cars currently protects
Solar Impulse’s solar cells. These cells are brittle and have no mechanical resistance,
but when covered with this film, they can be molded into the wing curvature without
breaking. The resin is UV resistant, waterproof and only 17 microns thick.
Ultra-light lighting system
Designed by Omega
To ensure visibility when landing after sunset, a system using LED lights was devel-
oped. The lights are protected by the same resilient plastic found in Swatch watches.
The entire system, including the protective glass, the wiring, power transformer and
connector, weighs just shy of 2 kg (4.4 lbs.) and consumes less than 100 Watts.
Solar cells as fine as a hair
Innovation by SunPower
With industry-leading efficiency (22.7%) Si2’s solar cells are only 135 microns thick, like
an average human hair. In comparison, the efficiency of solar panels used on homes is
of 16%. The best are those used on satellites (30%), but they are also too heavy for the
solar aircraft. There are 17,248 solar cells on Si2, chosen for their weight, energy and
efficiency ratio.
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4. GONDOLAS
For optimal maintenance, Solar Impulse engineers designed molded carbon fiber gondolas. Each
gondola contains a motor, a lithium polymer battery and a propeller.
Special additive for
increased energy density
Solution brought by Solvay
Technology already exploited by the automotive industry as well in portable electronics,
the PVDF binder (fluorinated polymer) increases energy density. It was developed for
use in the battery electrodes and as additive for making them.
Rigid, highly
insulating foam
Innovation by Covestro
This new foam has very thin pores, high rigidity and structural strength while remaining
lightweight. It is used in the best refrigerators and in the construction sector. To insulate
the cockpit from the radical temperature changes (-40°C/-40°F to +40°C/104°F) a
thermal isolation technology was conceived. The temperature of the batteries never
drops below -20°C (-4°F), temperature which could reduce their capacity.
Batteries with
lower oxidation
Invented by Kokam
Lithium-polymer battery cells used for Si2 are made with an innovative chemical formula
that has improved the oxidizing process. It’s a new technology and the best battery for
the project thanks to the weight, efficiency and lifespan ratio.
DC brushless sensorless
motors with exceptional
efficiency
Designed by Nicolas Wavre,
manufactured by Etel, magnets and
lamination stack by Vacuumschmelze
Si2’s motors have 97% efficiency, a technology for applications that are concerned with
power to weight optimization. Designed using newly developed materials and
technologies, a new treatment of the magnets and special slicing of the lamination stack
in very thin pieces reduced the power losses to an impressive minimum. Solar Impulse
is the first to use this breakthrough technology.
High efficiency DC/DC
converters and test bench
for electric systems
Built by Omega
This technology could be used to test the systems of electric cars. Developed especially
for Solar Impulse, the test bench enabled Solar Impulse engineers to validate the entire
chain of all the different electrical elements of the airplane. It provided them with the
necessary data to build the most efficient electric system.
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5. COCKPIT
The challenge for Solar Impulse electricians was developing efficient electronics with the lightest
materials on the market, all capable of functioning in extreme temperatures.
Highly sensitive flight
instrument with embedded
vibration alert system
Developed by Omega
Normal aircrafts are usually alerted of their bank angle when the aircraft is at 40° ; Si2’s
pilots are alerted already at 5°. The Omega instrument was conceived to allow the pilots
to keep track of their flight paths and bank angles while in flight and alerts them if the
angle of the wing exceeds the normal limit. The Instrument includes a vibration alert
system set inside the pilot’s sleeves.
Vibration device
for pilot awareness
Conceived by EPFL
The vibration device and man-machine interface allow the transfer of information
to the pilot while reducing the amount of information to be handled visually and
aurally.
Electrocardiogram
monitoring pilot’s fatigue
and vigilance level
Innovation by EPFL
The electrocardiogram has been tested by recently operated patients as a means to
inform their physician about any anomalies in real-time. It could potentially be used
by the automotive industry as a way to detect the driver’s level of attention. This device
accurately measures the heartbeat curve and is meant to be worn by the pilot to
monitor his level of fatigue and vigilance. The size of a matchbox, it immediately
transmits the information if a problem is detected.
Tailor-made pilot support
system for safety
Designed by Altran
Without the Stability Augmentation System (SAS) combined with the Monitoring and Alert
System (MAS) , the pilot wouldn’t be able nor be allowed to fly several days in a row.
The SAS actively maintains a straight and level flight path while the MAS monitors
independently the SAS in operation, the aircraft flight path and the overall system
health status.
In case anything abnormal occurs on the system side while the pilot is resting, the MAS
can disengage the SAS while alarming the pilot by several means (audio, visual and
tactile alarms) to force him to take back active control of the aircraft within 10 seconds.
Lifeline to the ground
Solution by Swisscom
The communication device transmits over 100 data items to the mission room, from
temperature of the motors to the position of the aircraft and tension in the accumulators.
Weighing less than 5 kg (11 lbs.) with an energy consumption not exceeding 50 watts,
this solution is the pilot’s lifeline to the ground and a great tool for fans to follow the
adventure online.
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6. PILOTS
During the circumnavigation of the globe, each pilot has to fly up to 4-5 days in a row. They will need
2.4 kg (5.2 lbs.) of food, 2.5 l (84.5 oz.) of water and 1 l (33.8 oz.) of sports drink per day : additional weight
that needs to be carefully calculated by the Solar Impulse team. In case of an emergency, the pilot seat
has an integrated parachute and life raft.
Intelligent fibers for a
stable body temperature
Conceived by Solvay
Intelligent nylon fibers are used in the pilot’s clothing. These are called “ intelligent ”
fibers because they stabilize the pilot’s body temperature. These fibers re-inject infrared
heat back to the surface of the skin when it’s cold but also prevent the pilot from
sweating during periods of intense heat.
Low-bandwidth solution
bringing the pilot to us LIVE
Solution by Swisscom
Sending videos is always a challenge especially in situations where the antenna has to
be small and lightweight. A low-bandwidth solution was implemented with only 50 kb/s
allowing videos of the pilots to be seen LIVE while in flight.
High-altitude medicine
for healthy pilots
Expertise provided by Hirslanden
Crucial medical advices are provided prior and during flights thanks to physicians and
specialists of high altitude medicine (aviation), counseling the pilots in nutrition science
as well as sleep and recovery methodologies.
Personalized diets for
a pioneer’s appetite
Developed by Nestlé Research
To ensure the pilot’s dietary needs are met during the long legs of the Round-the-World
flights, science-based personalized nutrition has been developed. Nestlé Research
managed to create a wide range of meals and snacks that can withstand extreme
variations in temperature and climatic conditions whilst providing the pilot with a healthy
balanced diet.
Business-class comfort
for transatlantic and
transpacific flights
New technology developed by Lantal
In order to allow the pilot to remain alert while flying the plane for flights up to 5 days
and 5 nights, the cockpit on Si2 offers enough space to stretch his legs. A reclining chair
and an ergonomic inflatable cushion ensure 100% comfort for the Round-the-World
mission flights.
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7. MISSION FLIGHTS
Apart from tailor-made flight planning and monitoring tools designed in tight collaboration between
Solar Impulse engineers, flight specialists and partners, there is ongoing cooperation between Solar
Impulse and national air traffic controllers for smooth and safe flights.
Real-time flight planning
and monitoring
Brought by Altran
PLATOO is the planning tool for real-time flight monitoring from the Mission Control
Center. This extremely precise system integrates : real-time meteorological data
processes, ultra-fine modeling of spectral phenomena and takeoff decision criteria.
The long-term stochastic (probability distribution) routing optimizers provide extremely
reliable analysis to define the Round the World flight strategies.
A satellite’s energy
system architecture
Developed by Altran
One of the project’s key successes was the energy system layout which optimizes
the energy system architecture. A satellite energy system specialist was involved in
the system’s design because of the similarities to the challenges and requirements
of satellites.
Technical and operational
support for smooth flights
Services offered by IATA
Representing more than 240 airlines, accounting for 84% of global air traffic, IATA provides
operational and technical assistance to Solar Impulse, facilitating take-offs, landings and
support to gain full cooperation of governments and air navigation services.
Safe flights in the
European airspace
Support provided by Eurocontrol
Eurocontrol offers operational assistance to Solar Impulse flights within the 38 European
member-state controlled airspace. Their systems and procedures has been adapted to
Solar Impulse’s specific characteristics while ensuring the smooth handling of some
30,000 flights daily and the integration of the solar airplane in very dense air traffic.
Fully covered all the way
Insured by Swiss Re
Corporate Solutions
The commercial insurer provides Solar Impulse with the security of full insurance
cover and is the sole insurer of this ambitious project to fly around the world powered
only by solar energy.
Public relations for
successful missions
Support provided by the
Swiss Confederation
Public relations and diplomatic skill at work provided by the Swiss Confederation ease
the way into establishing connections with airport authorities, public officials and
institutional representatives for successful mission flights.
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8. SUSTAINABLE MINDSET
Solar Impulse is supported by companies which strive to promote sustainability through their
technological innovations or their policies, thus taking part in the diffusion and the credibility of Solar
Impulse’s message.
Solar elevator
A world premiere by Schindler
Schindler is currently introducing a new solar-powered elevator to the market.
Furthermore, its innovative and environmental-friendly access and transit management
systems make an important contribution to mobility in urban societies. Moved by the
same spirit, Schindler and Solar Impulse join forces by embedding Schindler’s engineers
to provide Solar Impulse with support in applied electronics, advanced structures, new
technologies and in research and development.
Electric drives
to save energy
A system developed by ABB
ABB supplies technologies that improve the energy efficiency of propulsion systems
from one end of the chain to the other, from source to power distribution. The ABB
power conditioners installed worldwide, regulating the energy consumption of electric
motors, saved 400 TWh of electricity, equivalent to the annual consumption of more
than 100 million European households. The company is also the second largest
supplier of solar inverters, the technology that converts sunlight into electricity, and
is building a fast-charger network for electric vehicles in China.
Spreading the word
Using Google platforms & technology
For years, Google has contributed to the adventure by providing the Internet and
communications resources needed to let the World know of the Solar Impulse journey.
Google designers and engineers volunteered to help building the best possible user
experience across Solar Impulse online presence, and whether the plane is on the ground
or in the air, Google App Engine enables Solar Impulse’s Websites to run smoothly.
Solar Impulse hosts and broadcasts live discussions and performances to millions
of viewers, through their YouTube channel, thanks to Google Hangouts on air; and
with Google Expeditions, Solar Impulse’s technology is explained to students through
a large network of highschools, making a lasting impact on the young generation of
Internet users.
The carbon
abatement curve
A knowledge brought by McKinsey
The “ carbon abatement curve ” developed by McKinsey, provides a quantitative basis
for evaluating the effectiveness and costs of the various technologies that can bring
about a reduction in greenhouse gas emissions. The curve takes into account already
existing technologies as well as others that have a high probability of becoming
available by 2030, thereby encouraging the search for new techniques of energy-use
optimization and guaranteeing a sustainable future.
Celebrate sustainability
An initiative set in motion
by Moët Hennessy
Recognizing the role of excellence and innovation as two key drivers for progress, Moët
Hennessy views Solar Impulse as a project which illustrates the strength of
entrepreneurship and self-transcendence. These core values lead to great achievements
and are common to Moët Hennessy’s ambition of pursuing their development with the
permanent preoccupation of the future. With this initiative, they wish to celebrate the
men behind this adventure, marking their every step in the making of history.
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