Solar Impulse Solar Impulse

Solar Impulse 2 pilots Bertrand Piccard (right) and Andre Borschberg celebrate after Piccard landed their solar-powered plane at Moffett Field in Mountain View, Calif., on Saturday. Noah Berger/AP hide caption

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Noah Berger/AP

The Solar Impulse 2 airplane, piloted by Bertrand Piccard, gains altitude after taking off from Kalaeloa Airport in Kapolei, Hawaii during a test and training flight in April. Eugene Tanner /AFP/Getty Images hide caption

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Eugene Tanner /AFP/Getty Images

The Solar Impulse 2 landed in Hawaii in early July. The team behind the sun-powered airplane says it will be grounded until next spring. Solar Impulse | Revillard | Rezo/Solar Impulse | Revillard | Rezo hide caption

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Solar Impulse | Revillard | Rezo/Solar Impulse | Revillard | Rezo

Pilot Andre Borschberg of Switzerland sits aboard the Solar Impulse as a ground crew pushes the plane at the airport in Nagoya, Japan, prior to taking off for Hawaii. Toshifumi Kitamura/AFP/Getty Images hide caption

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Toshifumi Kitamura/AFP/Getty Images

The Solar Impulse takes off from Moffett Field NASA Ames Research Center in Mountain View, Calif., Friday, as a team member rides an electric bike alongside the plane. AFP/AFP/Getty Images hide caption

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AFP/AFP/Getty Images