Approval of God: Not Lem himself, who was already dead by then, but Bill Johnston translated Solaris into English directly from the original Polish. Unlike the Kilmartin-Cox translation, which Lem criticized (he was fluent in English), Barbara and Tomasz, his widow and son respectively, gave this translation their approval: "We are very content with Professor Johnston's work, that seems to have captured the spirit of the original."
Disowned Adaptation: Lem (who read English fluently) was unhappy with the English translation by Joanna Kilmartin and Steve Cox, claiming that it was of poor quality. For what it's worth noting, said translation was actually a translation of the French translation, which Lem himself claimed was "poor". It wouldn't be until 2011 that the book would get a direct translation from Polish to English by Bill Johnston. This translation earned the approval of his widow and son.
Science Imitates Art: As part of a NameExoWorlds campaign organized by the IAU, Poland got to name an exoplanet and the star it orbits around. The star was named Solaris, while the planet was named Pirx.
Writing by the Seat of Your Pants: When Lem started the book, describing Kelvin arriving at the station, he had no idea what it was going to be about.
was named Solaris, while the planet