Challenger
I think this was a cassette tape, in a handheld recorder in the cabin. It
was recovered from the debris. At some point, I think NASA acknoledged its
existence, but refrained from releasing it out of respect for the
astronauts' relatives. I saw a purported transcript in a tabloid that
seemed to match some of the leaked dialog, something like "hold my hand",
but who knows. It makes me sad, too.