Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer. Chosen as one of the original seven Mercury Program astronauts, he considered this first flight the greatest challenge and actively sought the assignment. Shepard's accomplishments in his career as an astronaut spanned a remarkable period in human achievement and in 1972 he walked on the moon as commander of the Apollo 14 mission. A true pioneer and intrepid explorer, Alan Shepard died Tuesday at age 74 after a lengthy illness.
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