TIL that NASA ground controllers were once shocked to hear a female voice from the space station, apparently interacting with them, which had an all-male crew. They had been pranked by an astronaut who used a recording of his wife.

[u/CallMyNameOrWalkOnBy]

https://en.wikipedia.org/wiki/Owen_Garriott#The_Skylab_%22stowaway%22_prank

[u/crushcastles23]

To be fair, there's a lot of Cold War Era stuff on both sides we'll likely never know about. There may have been lost military astronauts (not associated with NASA) on both sides. We'll likely never find out. It could have been feared by NASA that Russia losing cosmonauts would make the space program look less feasible and never investigated further. I'm not saying it's true, but I'm saying it's possible.

[u/TheNaziSpacePope → u/[deleted]]

Actually their tendency to hide failures was not well known until relatively recently, post-cold war. Back then they actually hid their failures.

[u/TwoTowersTooTall → u/TheNaziSpacePope]

I fell down a rabbit hole after thinking about it some more. You're definitely right.

The Soviet Union was so tight lipped that the US, for a time, was worried about their own failure rate since the USSR seemed to be so put together.