Final answer:
The main worry of Jim's youngest son about the moon mission was Option 3: He worried about his dad's safe return from the moon. This reflects the concerns for astronaut safety amid the historic achievements of the Apollo moon landings and the broader settings of NASA's activities during the space race.
Step-by-step explanation:
The main worry that Jim's youngest son had about the moon mission was the concern for his dad's safe return from the moon. This worry is deeply rooted in the human aspect of space missions, where the safety of astronauts is paramount. Despite the success of the Apollo moon landing in 1969, and the landmark achievement of astronauts Neil Armstrong, Buzz Aldrin, and Alan Shepard, every space mission involves risks that resonate with the family members of the astronauts. The personal fears and concerns often relate to the potential hazards during the mission, including the chance of malfunction, issues during the lunar landing or launch, and the potential health risks posed by space travel.
The historical context provided, such as President Kennedy's determination in the space race, Congress's support for NASA, and the challenges faced in theories about the moon's origin, underscores the complexity and ambition of space exploration endeavored by the United States during the Cold War era.