NASA's pumpkin-shaped balloon stays aloft for more than 42 days.
Balloons have long been a cheap way for scientists to get instruments above 99% of the atmosphere that confounds most experiments: nearly to the edge of space, but without the expense of rockets and the long development lead times of satellites. The Achilles heel, however, is that experiments are limited to days or a few weeks, before the balloons start to leak helium and fall back to Earth.
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