Also the nuclear reactor cores from Soviet US-A satellites: https://en.wikipedia.org/wiki/US-A https://en.wikipedia.org/wiki/US-A It mostly worked fine & 30 o

Also the nuclear reactor cores from Soviet US-A satellites: https://en.wikipedia.org/wiki/US-A https://en.wikipedia.org/wiki/US-A It mostly worked fine & 30 odd discarded cores are orbiting the Earth in a safe graveyard orbit. Just a few fell back.