Dr. Carl Sagan, an astronomer and Pulitzer-prize-winning author, played a leading role in the American space program since its inception. Beginning in the 1950s, Dr. Sagan developed what was to become a long-standing relationship with NASA as one of their consultants. He was also a part of the organization’s astronaut training program, working one on one with the Apollo astronauts by briefing them before their flights to the Moon. He also participated in experimental activities on a number of space programs including the Mariner, Viking, Voyager, and Galileo expeditions throughout the solar system, and beyond.