Keaton, never an actor with many lines, got through the production by speaking broken Spanish while reprising his amazing Vaudeville-inspired physical comedy schtick for the delight of Mexican audiences. The madcap plot involves Keaton as a WWII sailor, who thinking he is in Japan, unwittingly surrenders to the Mexican police. Due to be hanged as a spy, Keaton agrees to be sent up in an experimental rocket aimed at the moon in exchange for clemency. He lands not far from the original launch site, and cinematic hilarity ensues as Keaton attempts to communicate with what he thinks are inhabitants of the moon.
The popular director, Jaime Salvador, was known for his low budget "Ranchera" (mariachi musical genre) and comedy films in the golden age of Mexican film (Epoca de oro del cine mexicano), which explains this comedic venture into science fiction with Keaton in "Boom on the Moon." Salvador had a very long directing and screenwriting career from the post-WWII era to the early 1970s. Salvador's last production was released in 1971 - "The Professor" with Mexican film legendary star Cantiflas - five years before Salvador's death.
Thanks to wiki and Mexican film scholar Jose Luis Ramirez