The prologue voiceover refers to the Apollo Lunar Module as carrying three men to the lunar surface. While the Apollo Command Module had a three-man crew, the Lunar Module carried only two men to the surface.
The "U.S." rocket-ships journeying to Venus bear the red star of the USSR.
When contacting the men on Venus, the radio operator doesn't allow for the time for the radio transmission to travel to Venus and the time any radio transmission reply to travel from Venus to Earth.