Story summary.US sent a manned rocket ship to a lower earth orbit, the first such ship, to spy weather conditions over enemy territory & to warn of inbound atomic missiles. But it found near earth space already inhabited, in fact teeming, with ... ghosts - & that the man there in the rocket can see them & talk to them!
Here is the story's explanation of title: Beyond atmosphere, it's dead space. "Thanatos, that's Greek for death. May be instead of 'deadspace" you'd prefer 'Thanasphere'".
Fact sheet.First published: Collier's, 2 September 1950.
Related: Stories of Kurt Vonnegut.