John F. Kennedy uses all three main modes of appeal in his Moon Speech. Combined, the three of them give Kennedy credibility and help him get his message across to a wider audience.
Kennedy uses logos when he presents historical facts. In his metaphor that compresses the history of mankind, Kennedy presents some of the historical milestones that have defined humanity:
Last month electric lights and telephones and automobiles and airplanes became available. Only last week did we develop penicillin and television and nuclear power, and now if America’s new spacecraft succeeds in reaching Venus, we will have literally reached the stars before midnight tonight.
In this part, Kennedy focuses on the impact of technology to show the audience the fast pace of technological development. The logical argument is also meant to make the audience support his decision to send a man on the Moon.