The First Solar-Powered Flight Around the World
> BERTRAND PICCARD landed in Abu
Dhabi on July 25 after completing a two-day solo flight in the Solar Impulse 2 (SI2)
aircraft. The journey marked the end of
the first circumnavigation of the Earth in
a solar-powered airplane.
The idea came to Piccard in 1999 after
he flew around the world in a hot-air
balloon that relied on 3. 7 tons of liquid
propane. He wanted to do it again without
using fossil fuels. In 2002, he met Andre
Borschberg, an engineer and professional
pilot, who led the SI2’s feasibility tests.
SI2 has a 236-foot wingspan and
weighs around 2. 3 tons (about the same
as a car). It has four propellers and four
batteries, and its wings are covered in
17,248 solar cells. The solar cells take
energy from the sun to charge batteries
and run the motors, and the batteries
power the plane through the night.
The 24,800-mile trip was
accomplished in 17 separate flights,
which took 23 days in the air over 16
months. Piccard and Borschberg took
turns in the one-man plane. They covered
four continents, nine countries and two
oceans, and made a stop in Dayton, Ohio—
the Wright brothers’ hometown. They
broke 19 official aviation records along the
way. No fuel was ever used.
SI2 took off on March 9, 2015, and
successfully completed six legs of its
journey by the end of May. However,
while crossing the Pacific Ocean on May
31, inclement weather forced Borschberg
to make an unplanned stop in Nagoya,
Japan. Weather problems kept the team
grounded for another month.
Finally, the crew crossed the Pacific
Ocean on June 28. Borschberg spent 117
hours and 52 minutes in the air between
Japan and Hawaii, breaking the world
records for distance and duration for solar
aviation and for longest solo flight ever.
During this flight, SI2’s batteries
overheated and needed to be replaced,
halting the trip at the halfway point for
months. Once the plane was repaired, the
team had to wait again for the clear skies
and long days of the 2016 summer season.
After a long hiatus, Borschberg
and Piccard were able to take off
again. Between April and July, they
completed the final nine legs of their
They finished where they had begun,
in Abu Dhabi, bringing a 13-year project
to a close.
To learn more about SI2, visit www.