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Science & Environment
Science & Environment
Solar Impulse plane begins epic global flight
By Jonathan Amos
BBC Science Correspondent
9 March 2015
From the section Science & Environment
A record-breaking attempt to fly around the
world in a solar-powered plane has got under
way from Abu Dhabi.
The aircraft - called Solar Impulse-2 - took off
from the Emirate, heading east to Muscat in
Oman.
Over the next five months, it will skip from
continent to continent, crossing both the
Pacific and Atlantic oceans in the process.
Andre Borschberg was at the controls of the
single-seater vehicle as it took off.
He will share the pilot duties in due course
with fellow Swiss, Bertrand Piccard.
The plan is stop off at various locations
around the globe, to rest and to carry out
maintenance, and also to spread a
campaigning message about clean
technologies.
Before taking off, Borschberg told BBC News:
"I am confident we have a very special
aeroplane, and it will have to be to get us
across the big oceans."
"We may have to fly for five days and five
nights to do that, and it will be a challenge.
"But we have the next two months, as we fly
the legs to China, to train and prepare
ourselves."
The project has already set a number of world
records for solar-powered flight, including
making a high-profile transit of the US in
2013 .
But the round-the-world venture is altogether
more dramatic and daunting, and has required
the construction of an even bigger plane than
the prototype, Solar Impulse-1.
This new model has a wingspan of 72m, which
is wider than a 747 jumbo jet. And yet, it
weighs only 2.3 tonnes.
Its light weight will be critical to its success.
So, too, will the performance of the 17,000
solar cells that line the top of the wings, and
the energy-dense lithium-ion batteries it will
use to sustain night-time flying.
Operating through darkness will be particularly
important when the men have to cross the
Pacific and the Atlantic.
The slow speed of their prop-driven plane
means these legs will take several days and
nights of non-stop flying to complete.
Piccard and Borschberg - whoever is at the
controls - will have to stay alert for nearly all
of the time they are airborne.
They will be permitted only catnaps of up to
20 mins - in the same way a single-handed,
round-the-world yachtsman would catch small
periods of sleep.
They will also have to endure the physical
discomfort of being confined in a cockpit that
measures just 3.8 cubic metres in volume -
not a lot bigger than a public telephone box.
Flight simulators have helped the pilots to
prepare, and each man has developed his own
regimen to cope.
Borschberg will use yoga to try to stay fresh.
Piccard is using self-hypnosis techniques.
"But my passion also will keep me going,"
said Piccard.
"I had this dream 16 years ago of flying
around the world without fuel, just on solar
power. Now, we're about to do it. The passion
is there and I look forward so much to being in
the cockpit."
The support team is well drilled. While the
mission will be run out of a control room in
Monaco, a group of engineers will follow the
plane around the globe. They have a mobile
hangar to house the plane when it is not in
the air.
It is not at all certain Solar Impulse will
succeed. Computer modelling suggests the
ocean crossings are feasible, given the right
weather conditions.
But that same modelling has shown also that
there may be occasions when the team simply
has to sit tight on the ground for weeks before
a fair window opens.
"Last year, we had a very good exercise. We
went around the world virtually, but with
actual conditions," explained Raymond Clerc,
mission director.
"For the Pacific crossing, it was an easy
decision. We had a very good window on 2
May. But when we were on the East Coast of
the USA, we had to look to cross the Atlantic
and we had to wait 30 days to find a good
window to cross the Atlantic. And then it was
easy - 3.5 days and we were in Seville, [Spain]
," he told BBC News.
If the pilots should come unstuck over the
Pacific or the Atlantic, they will bail out and
use ocean survival gear until they can be
picked up by a ship.
Of the two protagonists, Andre Borschberg
perhaps needs a little more introduction.
A trained engineer and former air-force pilot,
he has built a career as an entrepreneur in
internet technologies.
Bertrand Piccard, on the other hand, is well
known for his ballooning exploits.
Along with Brian Jones, he completed the first
non-stop, circumnavigation of the world in
1999, using the Breitling Orbiter 3 balloon.
The Piccard name is synonymous with pushing
boundaries.
Bertrand's father, Jacques Piccard, was the
first to reach the deepest place in the ocean (a
feat achieved with Don Walsh in the Trieste
bathyscaphe in 1960). And his grandfather,
Auguste Piccard, was the first person to take
a balloon into the stratosphere, in 1931.
Jonathan.Amos-INTERNET@bbc.co.uk and
follow me on Twitter: @BBCAmos
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