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     Recently, a solar-powered (太阳能动力的） plane took to the sky for the first time. It passed an important test on the way to travel around the world.
    The plane took off from an airport（飞机场）in Switzerland. It slowly rose above the fields and into the sky.
   “There has never been an airplane of that kind that could fly—never an airplane so big, so light, using so little energy.” said Bertrand Piccard, a leader of the project.
    During the 90-minute flight (飞行）, the plane did several turns. It climbed nearly 1. 6 km above the countryside.
    Engineers（工程师） plan to test a night flight（飞行）before July. Then they will use the results（结果）of the tests to build a second plane. They plan to travel around the world in that plane in 2012.
    “We want to fly it day and night with no fuel(燃料）,” Piccard said. Piccard and pilot (飞行员）Andre Borschberg will take the plane around the world. They will make a few stops to change places and rest after a long time in the air--and to show off their airplane.
     The plane will fly at 70 km per hour on average(平均）. That is faster than a bike and slower than a car. The pilots will keep the plane in the air for up to five days at a time.