Was a manhole cover really launched into space?

In the short history of human space travel, officially, the first man-made object in space was the satellite Sputnik.

Launched by Russia on October 4, 1957, it was just 58cm wide, about the size of a beach ball. In escaping Earth, this little metal sphere kicked off the epic space race between Russia and the US, which would culminate with Neil Armstrong and Buzz Aldrin landing on the Moon.

But unofficially...