The Grapevine
Secrecy was part of the Space Race because it occurred during the Cold War. Rumors spread like wildfire, and some are still around today because they were so persuasive. The main one is that the Soviets sent humans to die while in space.
Lost Cosmonauts
People started whispering about the Soviet cosmonauts who were lost at the beginning of the Space Race. Stories focused on people dying while returning or developing mental breakdowns from the expeditions. Rumors also spread that cosmonauts were abandoned in space.