There are yet further options that a translator might consider at least fleetingly, such as these (and doubtless many more):
(7) use the English word “science” and insert a scholarly footnote explaining that Lem’s original story was in Polish and that the Polish for “science” is nauka, for which, unfortunately, there is no English rendering that begins with “n”;
Option (7) is—I can find no better phrase for it—a total wimp-out. And yet, in the course of reading this book—especially Chapters 9 and 17—you will meet translators, some famous, who prefer to translate in just that style, and some of whom even try, using pompous scholarly language, to demonstrate the superiority of their wimp-stance. This option is sad.