Nicholas Johnson is chief scientist for orbital debris for the United States space agency.

VOA: special.2009.04.01

But young Nicholas Johnson, a conundrum-solving kid who has tinkered with puzzles since he was a toddler, says he has the answer.

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According to NASA there are about 20, 000 pieces of space junk bigger than 10cm (3.9 inches) and its chief scientist for orbital debris Nicholas L. Johnson says most robotic satellite missions are vulnerable to particles as small as 5mm (0.2 inches) -- there are thought to be millions of those in orbit.

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