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Future Tech: 

Everything you need to know about Solar Impulse


Solar Impulse will travel around the world using only solar power.

They said it couldn’t be done, but in 1999 Swiss psychiatrist Bertrand Piccard was the first person to fly around the world in a hot air balloon. The non-stop journey carried the explorer 25,361 miles in all conditions, over an incredible period of 19 days, 21 hours and 47 minutes.

His next trick? Flying around the world again, of course, only this time it isn’t in a balloon, but a solar-powered plane that’s currently crossing the globe without a single drop of fuel. The trip is expected to take five months.

How is that possible?

The first thing to know is that Solar Impulse 2 hasn’t embarked on one non-stop journey, but plans to complete the journey in 13 legs. Having set-off from Abu Dhabi back in March, the plane will fly east, passing through stops including Oman, Mandalay, Nanjing, Phoenix, Arizona and New York, before making the long trip to Southern Europe, Africa and back to Abu Dhabi.

The longest legs of the journey are those crossing the Atlantic and Pacific oceans, both of which are expected to take five days each.

What happens overnight?

Good question – after all, what use is a solar-powered plane under a blanket of darkness? Luckily for Piccard and his co-pilot André Borschberg, Solar Impulse 2 comes well-equipped.

In order to cross the oceans on just solar power, the plane needs to be super lightweight, and it comes in at around 5,000lbs. Almost half of that weight is made up of lithium batteries which are recharged during the day by the 17,000 solar cells built into the plane’s body. That explains its enormous wingspan.

Solar Impulse flies a little slower overnight so as not to drain the energy its stored up during the day, and it also needs optimum weather conditions to complete its journey. That means plenty of sun, so let’s hope Piccard and Borschberg have packed their factor-50.

/ Photo: Ackerman /

We’re walking on sunshine (whah-oh!), and don’t it feel good! // Photo: Ackerman,

Who else is behind Solar Impulse?

While it’s down to Piccard and Borschberg alone to fly the plane itself, Solar Impulse has a team of more than 80 engineers, technicians and mission controllers on-land to back them up. The project received financial and technical backing from more than 100 partners, but these mostly come from outside the aviation industry. In an interview quoted by Tech Digest, Piccard explains: “It wasn’t the people selling candles who invented the lightbulb.”

What will it be like on-board?

As for the pilots themselves, it’s going to be grueling a flight – and we’re not just talking about stingy legroom. The plane can’t carry an auto-pilot function so will be manned by the two pilots in rotation, who will be allowed to sleep for only 2-3 hours during any 24 hours period.

Aside from keeping their eyes open, there’ll also be a wildly fluctuating temperature. As the cockpit is not pressurized, the two pilots can expect temperatures to vary between 40c and -40c. They’ll be wearing thermal insulation to help them adjust, but, put it this way – rather them than us.

When can we all fly solar-powered?

Not so fast. If successful, Solar Impulse 2 may prove that a plane can travel across the globe without fuel, but a plane carrying passengers? That’s another question. The lightweight design plays a big part in getting it through those longer journeys, and once you add the considerable bulk of GoExplore’s editorial team to the passenger cabin, that thing is going down quicker than you can say “maybe this isn’t such a good idea.”

It looks like we’re sticking with Budget Air for now then, leaving the science to the scientists, and the exploring to the explorers.

Where is the plane now?

Why not have a look? You can follow the Solar Impulse’s journey via blog and live stream over on the project’s website. It’s currently on it’s tricky eighth leg – hovering over the Pacific Ocean from Nagoya to Hawaii.

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