After the war, he served in the United States Air Force Reserve, and retired with the rank of colonel.

The latter novel features a land and sea expedition across the superjovian planet Mesklin to recover a stranded scientific probe.

They are; for the reader of a science-fiction story, they consist of finding as many as possible of the author's statements or implications which conflict with the facts as science currently understands them.

For the author, the rule is to make as few such slips as he possibly can... Certain exceptions are made [e.g., to allow travel faster than the speed of light], but fair play demands that all such matters be mentioned as early as possible in the story...Clement was a frequent guest at science fiction conventions, especially in the eastern United States, where he usually presented talks and slide shows about writing and astronomy.

[3][4][5] For the 1945 short story "Uncommon Sense" he received a 50-year Retro Hugo Award at the 1996 World Science Fiction Convention.

Mission of Gravity, first published as a serial during 1953, was named best foreign novel by the Spanish Science Fiction Association in 1994 and it was a finalist for a 50-year Retro Hugo Award in 2004.