“Desertion,” Clifford D. Simak, 1944 – Two volunteers who have had their bodies turned into “Lopers” so that they can survey the surface of Jupiter disappear. The administrator can’t in good conscience send another volunteer to look for them, so he transforms himself and his faithful dog into Lopers. Once in his new body, he decides not to return to humanity.
Comments: Read in Great Tales of Science Fiction, ed. Silverberg, who notes: “‘Desertion’ is his finest short story, written in anger and frustration when he heard the first reports of what was happening in the death camps of Nazi-occupied Europe.”
Author: Wikipedia: “Clifford Donald Simak (August 3, 1904 – April 25, 1988) was an American science fiction writer. He was honored by fans with three Hugo awards and by colleagues with one Nebula award and was named the third Grand Master by the Science Fiction and Fantasy Writers of America (SFWA) in 1977.”