This Plane Could Fly Forever Without Stopping

With good weather, the Solar Impulse 2 could theoretically fly forever. It's circling the globe now.
Flying around the world, powered by the sun
This is the Solar Impulse © Solar Impulse/Revillard/
By Josh Sampiero

The Solar Impulse 2 is a modern marvel, a plane built to fly around the world powered only by the sun. Flying above the clouds with good weather, it could conceivably fly on and on, but don't get nightmare scenarios of an endless flight in your heads — there's no way they could pack enough snacks and sodas to keep you content in your seat. Also, you wouldn't have a seat.

No, this craft is a technical leap forward rather than a commercial experiment. In March, the plane started a round-the-world journey in Abu Dhabi, steered by two Swiss pilots, André Borschberg and Bertrand Piccard. With 6,700 miles behind them, Borschberg will now face the greatest challenge yet: crossing the Pacific Ocean, from Japan to Hawaii. We chatted with him to get the details.

Solar Impulse, the plane without power
In the cockpit of the Solar Impulse 2 © Solar Impulse/Anna Pizzolante/ You’ve got a long flight ahead of you ...

André Borschberg: The leg from China to Hawaii is the longest leg in the journey. It’s the first time one pilot will fly solo for that long. The question is if I can keep up my energy. The challenge will be to keep the right attitude and mindset to make the right choices. The only way to fly five days and five nights is to forget about the present and focus on the moment.

Flying to Hawaii, by the numbers

But you had to make an unscheduled stop ...

Originally, we took off from Nanjing, China. But after two days, weather shut us down and we were forced to land in Japan — there was simply no choice. It was unplanned, but the Japanese were incredibly helpful in getting the plane on the ground and allowing us to set up the mobile hangar.

Solar Impulse, the plane without power
Clouds like this forced the plane to land © Solar Impulse/Andre Borschberg

What gets the plane in the air, and conversely, keeps it on the ground?

Weather plays a role in different ways. We need to avoid turbulence, strong wind and strong thermals. Since we use solar energy to charge the plane, we also need to be in the sun as much as possible. So we’ll occasionally fly somewhere else.

It looks fast.

It isn’t. The plane only travels 45 miles per hour. You can have duration or speed, and we chose duration. In good weather, the plane can stay in the air forever.

You climb up to 28,000 feet every night. Why so high?

Altitude is a way to store energy. We climb to 28,000 feet and it gives us time and lets us use less of the battery. It increases the chance we’re still in the air when the sun comes up the next morning.

Flying around the world, powered by the sun
This is home for days at a time... © Solar Impulse/Pizzolante/

Over 120 hours in the plane is a long haul. Is the seat economy or first class?

It’s a good business-class seat. You can put the backrest completely horizontal! It’s also extremely soft.

Soft enough to sleep?

Sleeping is one way to rest, but it will only be 20 minutes at a time. I’ll use other techniques of yoga, meditation and breathing. They’re really powerful. Relaxing the mind and body, but keeping attention on the aircraft.

What keeps you busy?

During the flight there’s a lot to do. I don’t expect to have much time. There’s a lot of communication with the ground to learn about the weather, see what’s going on and find the optimal path to the destination.

Are you scared at all?

I work hard to prepare. We’ve done rescue training to make sure we can use the parachutes, but also as a way to put difficult moments out of the mind. I’m not afraid; I’m excited. That forces you to prepare everything. It makes you ready.

Want to know more about the Solar Impulse project? Follow it live.

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