At the start of the end credits, there is a title card that says "For Lionel Jeffries 1926 - 2010." Lionel Jeffries played Joseph Cavor in First Men in the Moon (1964).
As they approached the moon, an alarm number 1202 occurred and Cavor said "I'd ignore it". This is a reference to the "1202 Alarm" that the Apollo 11 LEM encountered when it approached the lunar surface in 1969. The astronauts on Apollo 11 similarly ignored the alarm as it was related to a radar system overload, and ground control believed they would have sufficient processing capacity to land anyway.
The film takes place in 1909 and on July 20, 1969.