Mark Armstrong and Rick Armstrong said that this film contained the most accurate portrayal of their father Neil Armstrong and their mother Janet Armstrong.
William Safire, one of Richard Nixon's speechwriters, had prepared a statement to be delivered by the President in the event the Apollo 11 mission had failed. NASA White House Liaison, astronaut Frank Borman, suggested to Safire that the President should be prepared to address a catastrophic mishap with the mission. Since the most dangerous parts of the mission were the landing and take-off, a mishap most likely meant the astronauts would either crash on the moon or be unable to depart; in either case left stranded there. Safire wrote a short speech titled "In the event of moon disaster" for such a contingency, but did not deliver it to Nixon. After the success of the mission, Safire quietly entered the speech into the presidential records where it remained until it was de-classified and released to the public in 1999. The first line of the speech reads: "Fate has ordained that the men who went to the moon to explore in peace will stay on the moon to rest in peace."
In the breakfast scene just before Apollo 11 launched, NASA sketch artist Paul Calle was played by his own son Chris Calle.
The "1201" and "1202" alarms that sounded during the lunar descent was an indication that the computer was receiving more data than it could process. The procedure to fix this was to cycle the switch, which essentially ended the bottleneck. This was not the last time this error had been encountered in an Apollo flight. When Apollo XII was struck by lightning during its launch, it also triggered a 1202.
A prominent character in this film is Donald K. Slayton aka Deke Slayton. He was one of the original Mercury astronauts but was grounded due to heart palpitations. Choosing to stay with NASA, he became its first Chief of the Astronaut Office and the Director of Flight Crew Operations. His persistence would eventually pay off, as he was declared healthy in 1971 and finally went into space in the joint American/Soviet Apollo Soyuz flight in 1975, some 14 years after the first manned Mercury mission.