Looking for a science fiction story, probably from the 1960s, about a scientist on a space expedition who must send explorers to the surface of a planet with an inhospitable atmosphere. In order to do that, he needs to transform them into bizarre-looking creatures. The story begins when several explorers have simply disappeared after going to the planet. The scientist decided that the only moral thing to do is to transform himself and his dog, and explore the planet surface himself. Does anyone remember this?
This would be the story "Desertion" which became part of the fix-up novel City by Clifford D. Simak. It was first published in the November 1944 issue of Astounding Science Fiction. It's been published multiple times since then.
From Wikipedia https://en.wikipedia.org/wiki/City_(novel):
Simak's version of Jupiter is a cold, windswept, and corrosive hell where only advanced technology allows the station to exist at all. A scientist is accompanied by Towser, his tired and flea-bitten old dog. But there is a problem. Men permanently transformed to survive unaided on Jupiter's surface leave the station to gather data and inexplicably fail to return. Finally, the scientist transforms himself and his canine companion into the seal-like beings that can survive the surface. They leave the station in their new form and experience Jupiter as a paradise. Towser's fleas and irritations are gone and he is able to talk telepathically to his former master. Like the previously transformed station personnel, the scientist decides never to return.