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From life on Mars to a robot on a comet: The year in space exploration

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December 26th, 2014

From life on Mars to a robot on a comet: The year in space exploration

It’s been a historical year for NASA, who discovered signs of life on Mars and used a robot to land on a speeding comet. But there was also tragedy in space, when one of Virgin Galactic’s test pilots was killed while helping to make the dream of commercial space flight a reality. NBC’s Keir Simmons reports.

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