I read an ex-library book in the mid-1980's (so suspect it was written pre-1975) and the story was set on Pluto.
The protagonist was a space pilot who, for a reason I can't remember, lands / crashes on that distant world - and dies ... Only, some time later, to reawake - alive!
It turns out that a great deal of time has passed. And an alien civilisation, living on Pluto, has found the pilot's body. These aliens clone the body, and then duplicate man's mind.
The pilot 'wakes up'- but can't see anything. He's told not to worry. As time passes, he realises something is amiss. It's then that the aliens explain things: while they've successfully duplicated his mind, so far they've not inserted it into the cloned body - so he exists as pure consciousness.
Finally, both body and mind are joined. The man is thankful for being alive. He now sets about living amongst the aliens. But he's drawn to his old ship, and wants to head off to distant Earth ...
My memory of some of the details regarding the plot of this story are hazy, but I've outlined what I can remember. I've no idea when the book was first published, nor what its title is.