The story is set on a very rapidly rotating highly oblate planet named Mesklin; its "day" is just under 18 minutes long, and its surface gravity varies between 700 g at the poles and 3 g at its equator.

[1] Boucher and McComas found Mission "compact and unified, with a good deal of adventurous excitement" and characterized it as "a splendid specimen of science fiction in the grandest of grand manners.

[3] The story is “noteworthy not only as an impressive piece of planet-building, but as the first SF novel built on actual observational data involving another possible solar system”,[4]: 170  making it an early and often-praised example of macrocosmic worldbuilding hard science fiction.

The novel is frequently invoked in discussions of the sense of wonder, the sensation of dawning comprehension and understanding of a larger context for a given experience, that many readers of science fiction point to as the reason why they pursue the genre.

Neil Barron identified the story as displaying several characteristics of the classical epics such as beginning in medias res and a divine intervention of sorts by the assistance provided to the Mesklinites by the human character Lackland.