2019 marks the 50th anniversary of NASA’s Apollo program. The mission’s crewed flights began in 1968 with the first lunar circumnavigation; on July 20, 1969 Neil Armstrong became the first human to step foot on another planet. By the end of 1972 Apollo’s funding was cut short and NASA’s moon explorations were over. From 1969 to 1972 there were eight crewed missions and 12 astronauts walked on the surface of the moon, exploring and doing ...