She holds the NASA record for time spent in space. This week she headed back

Astronaut Peggy Whitson, probably thinking about breaking records or being in space.Bill Ingalls/NASA/NASA via Getty Images Before this week, Peggy Whitson had spent a cumulative 665 days in space over her career, giving her the NASA record.She's not done yet.Who is she?Whitson, 63, is a biochemistry researcher, retired NASA astronaut, and colloquially known as "the space ninja."

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