Milestones in solar aviation

• Pages: 12-14

The first night flight by a solar-powered aircraft –

a feat unimaginable only a few years ago, and ac-

complished by the elegant

Solar Impulse

in July

this year. A few weeks later, the

Zephyr

, a solar-

powered unmanned drone,1returned to earth af-

ter 14 days in the air. These two historic, record-

breaking feats demonstrate the enormous

potential of renewable energy and new technolo-

gies. They promise to transform our perception of

what is possible.

Launched in 2003 by pioneering adventurer

Bertrand Piccard and entrepreneur and aviation

enthusiast André Borschberg, the ambition of

the Solar Impulse project is “to contribute to the

world of exploration and innovation, to the cause

of renewable energies. To demonstrate the im-

portance of the new technologies in sustainable

development and… to place dream and emo-

tion at the heart of scientific adventure.”

The inspiration

On March 21, 1999, after 19 days, 21 hours and 47

minutes in the air, Bertrand Piccard and Brian

Jones touched down in the Egyptian desert in

their hot-air balloon, the

Breitling Orbiter 3

. This, the

first, non-stop circumnavigation of the earth in a

balloon, was widely hailed as the last great pio-

neering feat of the 20th century. On landing,

Messrs. Piccard and Jones had only 40 kgs left of

the 3.7 tons of liquid propane with which they be-

gan their adventure (in the Swiss town of Château

d’Oex). Frustrated by the constraints of fossil fuel,

Mr. Piccard resolved to repeat the experience, but

without using fossil fuels or polluting emissions.

Thus was born the Solar Impulse project.

The

Solar Impulse HB SIA

, the first manned aircraft

able to fly day and night propelled solely by solar

energy, has the wingspan of a large airliner (63.40

meters), and the weight of a midsize car (1,600

kgs). It is covered by some 12,000 solar cells

which run four electrical engines and charge 400

kgs of lithium batteries.

The mission of the flight on July 7 and 8 was to

“demonstrate the feasibility of a complete day-

night-day cycle propelled solely by solar energy.”

After six years of intense effort, countless calcula-

tions and simulations and 11 test flights, the 70-

strong Solar Impulse team completed this “un-

precedented” and “revolutionary” aircraft. And on

July 8, 2010, at 9 a.m.,

Solar Impulse

, with co-

founder André Borschberg at the controls,

touched down after a flight of 26 hours, 9 min-

utes and 10 seconds. It was the “longest and high-

est” flight in the history of solar aviation – a mile-

stone in the field.

On leaving the cockpit, Mr. Borschberg said, “I’ve

been a pilot for 40 years now, but this flight has

been the most incredible one of my flying career.

Just sitting there and watching the battery-

charge level rise and rise thanks to the sun… and

then that suspense, not knowing whether we

were going to manage to stay up in the air the

whole night. And, finally, the joy of seeing the sun

rise and feeling the energy beginning to circulate

in the solar panels again!” He added, “I have just

flown more than 26 hours without using a drop of

fuel and without causing any pollution.”

Flight Report

Pilot: André Borschberg, CEO and co-founder

Take-off time: 07/07/2010 – 06:51

Landing time: 08/07/2010 – 09:02

Flight duration: 26 hours 9 minutes 10 seconds

Maximum speed: 68 knots / 125.9 km/h

Average speed: 20.6 knots / 38.2 km/h

Maximum altitude: 8,720 m (above sea level)

For Mr. Piccard, the flight “was a crucial step for-

ward” in lending credibility to the potential of re-

newable energy and clean technologies.

Following Solar Impulse’s maiden flight on April 7,

2010, Mr.Piccard noted, “our future depends on

our ability to convert rapidly to the use of renew-

able energies.

Solar Impulse

is intended to demon-

strate what can be done already today by using

these energies and applying new technologies

that can save natural resources.”

MILESTONES

IN SOLAR AVIATION

OCTOBER 2010

12

“All that is impossible

remains to be achieved”

Jules Verne

1 A high-altitude long-

endurance (HALE)

unmanned air system

(UAS)