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Interview: 'Solar Impulse' Pilot Discusses Impact Of Record-Breaking Flight

Andre Borschberg, in the cockpit of "Solar Impulse," celebrates after completing his historic flight.

Andre Borschberg, in the cockpit of "Solar Impulse," celebrates after completing his historic flight.

Earlier this month, the Swiss-built "Solar Impulse" airplane flew for more than 24 hours powered only by the sun. The prototype aircraft stored electricity in batteries, which allowed it to stay aloft during the night.

Mohammad Reza Kazemi, a correspondent for RFE/RL's Radio Farda, recently spoke to the pilot of the "Solar Impulse," Andre Borschberg, about his historic flight.

RFE/RL: Mr. Borschberg, can you describe your successful 26-hour test flight of the "Solar Impulse?" It was a first, a new innovation.

Andre Borschberg:
It was quite unbelievable, from many perspectives. First of all, it was a beautiful day, so the scenery -- the day flight, the sunset, the night flight, the sunrise -- all that was absolutely beautiful. But, of course, the highest and most extraordinary moment was just following sunrise when the solar generators started to be alive again and started to feed energy back into the motors and the batteries. That was a great time.

RFE/RL: So through the whole night you had nothing, no energy?

Through the whole night I used no energy from the sun, of course, but I used the energy we stored during the day. The idea is that by flying during the day we collect solar energy to propel the aircraft but also to feed the batteries and climb to a high altitude -- up to 9,000 meters. At sunset, I flew down to a low altitude -- about 2,000 meters -- which took about three hours, during which time I did not have to use energy from the batteries. And then for the remaining part of the night I used the energy that we stored in the batteries. Of course, with the hope to still be in the air the following day, which happened very successfully.

RFE/RL: So you could have continued your flight after the sun came up?

Yes, and that [is] also the demonstration we want to do. We could continue and do the same cycle again -- collecting energy to refuel the batteries. You have to understand, we still had about 40 percent battery charge [in the] early morning, so we were extremely successful [in] not using too much energy during the flight. That was an excellent [result] for us.

RFE/RL: Were you afraid during the flight?

No, because I think the flight was very well prepared. Of course, the cabin and the cockpit [are] quite small. It was very cold, because at 9,000 meters the outside temperature is -30 or -35 degrees [Celsius]. But the mission went very well. The aircraft was flying well, too, so it was a great moment.

"Solar Impulse" had the wingspan of a jumbo jet but its weight was only that of a midsized car.
RFE/RL: You had no heater in the cabin?

I had no heater, but I had a special outfit, and I was able to inflate this outfit with air to increase the insulation. So, in fact, it was almost too warm and that was the difficulty when I was flying at low levels because I was sweating a lot. So we were too much on the warm side during the entire flight.

RFE/RL: I saw pictures of the plane and the videos. The cabin for the pilot was very small. What did you do during this time? Twenty-six hours is not a short time.

No, it's not a short time. But I mostly flew the "Impulse" because the "Impulse" doesn't have a lot of pilots. So it has to be flown constantly, so [there is] no way to sleep. [You can] rest a little bit, yes, but [there is] no way to sleep. So I was very focused on flying the airplane. I was quite focused also [on] discussing the flight strategy and the flight tactics with mission control -- the team which is on the ground. So [I was] quite busy for the whole flight.

But [I had] at the same time the possibility, of course, to enjoy the scenery and to be very conscious about what was happening. I'm used to flying fighters and jet airplanes where the speed is very high and the pressure on the pilot is very high, as well. So in the "Solar Impulse" you have time to be conscious of what you're doing and that's also something that's very special.

RFE/RL: Regarding energy usage, the audience had the opportunity to follow you live, right?

Yes. We have a website and on the website we also showed what was happening using cameras in helicopters and also using onboard cameras. On the website, we also had part of the information that we had in the cockpit and that we had on the ground in the telemetry center showing how much energy we [were using], how much energy was being generated by the solar generator, the altitude of the airplane -- all the important flight parameters.

But, you know, the energy question is paramount in the project. The amount of energy we collect, of course, is modest because it's just coming from the sun. So we have to find solutions to build an airplane which uses very little energy. On average, the power we have is the power of a scooter, and that led us to build an airplane with the size of a jumbo jet -- about 65 meters wingspan -- with the maximum weight of a midsized car -- so extremely light.

RFE/RL: One of the challenges was landing. You said the wings were very long and it was not easy to maintain balance.

Yes, landing is always a challenge, especially with such an airplane because of its size and [its sensitivity] to all the turbulences, all the movements of the atmosphere. And after 26 hours you get a little bit tired. So I really had to concentrate to do a good job. But it worked [out] fine. But I was happy to be back safe on the ground.

RFE/RL: Do you think this could mark the start of a revolution in aviation?

I think it's the start, certainly, of a new era but not necessarily only in the aviation industry. I think what we wanted to do with this project and what we will do also in the future is to demonstrate what we can do with existing technologies. But first to show the potential of renewable energy. If we can fly with this energy, we can certainly use it extremely well on all applications or on many applications on the Earth.

And also with existing technologies, we can keep the same quality of life, keep the way we live, but using much less energy than what we used to [use]. I think we are. I mean, if I look [at] Switzerland -- but maybe also in your country -- we are totally dependent on fossil [fuel] energy, which will at a certain stage disappear. Or at least we will see the prices of this fossil [fuel] energy go up very strongly, and we need other sources. We need other types of energy. And the best way to reduce our dependency is to reduce our consumption. And we hope that this project demonstrates that this is feasible.

RFE/RL: Did you get any feedback from the aviation industry?

IATA, which is the International Air Transport Association, which groups all the airlines, has taken our project as the first step toward clean aviation. And they have said the goal for airlines [is] to reduce CO2 emissions by 50 percent in 40 years -- by 2050. It's a long time, but you know in aviation progress is not very fast. It takes time to [make progress in] airplanes. And if we don't start working on these solutions today, we will never have them tomorrow, or at least in 40 years.

RFE/RL: When do you think the first passengers will be able to board solar planes?

See, it's difficult to say. You have to position yourself in the last century. When the Wright brothers made the first flight in 1903, I think one of the Wright brothers said at the time it would not be possible to fly over the Atlantic. Twenty-five years later, Lindbergh made the first [trans-Atlantic] flight. He was alone in the airplane. And it took another 25 years for 100 passengers to fly over the Atlantic, as well.

So I think it's difficult to set the date. But definitely, if we want to reduce the dependency on oil, we have to start working on new solutions today. Is this going to be a hybrid technology? Again, it's difficult to say, but we'd like to start.

RFE/RL: What will be your next project?

The next project is to build a second airplane with which we'd like to fly around the world. This is scheduled for 2013 [and is meant] to re-demonstrate that this technology has a future, that this technology is providing the energy savings that we advocate. And that's what we’re going for over the next few years.