During the ascent the balloon is constantly widening because of the decrease of atmospheric pressure, and at a certain height it will inevitably burst.

在上升的过程中，随着气压的降低，气球不断膨胀，到一定的高度，气球就会爆破。

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Achievement: Mr Harrison guided the balloon to a height of 22 miles above the earth's surface and was able to recover the camera as it parachuted back down to earth using a sat-nav device.

完成过程：哈里森先生使用卫星导航设备，先引导气球到达距离地球表面22英里的高空，然后在相机通过降落伞返回地面时，恢复相机的照相功能。

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Small balloon height.

气圈高度小。

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"People were jumping out of the balloon from about the height of a seven-storey building, " Cherry Tohamy, an Egyptian who was in another balloon, told the BBC.

BBC: Egypt balloon crash: Two Britons and UK resident die

Unlike a conventional hot air balloon where the height is controlled by a burner, the gas balloons are filled with hydrogen and controlled by releasing gas to go down and throwing out ballast to go up.

BBC: Wiltshire

Finally, at a height of almost 19km, the balloon burst and the payload fell back to earth helped along by a parachute.

BBC: Giant weather balloon carries out its sky mission