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Visitors gather around the Apollo 11 command module “Columbia” that carried astronauts Neil Armstrong, Buzz Aldrin, and Michael Collins on their historic voyage to the Moon and back on July 16 to 24, 1969, at the Smithsonian Institution’s National Aiur and Space Museum in Washington Saturday, Aug. 25, 2012. Neil Armstrong who became a global hero when as a steely-nerved pilot made "one giant leap for mankind" with a small step onto the moon died Saturday. He was 82. (AP Photo/Manuel Balce Ceneta)

NASA testing Apollo 11 rocket engine

Engineers hope to gain valuable knowledge from the engine, which was originally supposed to power the Apollo 11 moon mission in 1969 but was grounded by a problem.