Quite strange that the article does not mention Clarke's Rendezvous with Rama (which were published just 2 years before that "summer study", by the way) https:

Quite strange that the article does not mention Clarke's Rendezvous with Rama (which were published just 2 years before that "summer study", by the way) https://en.wikipedia.org/wiki/Rendezvous_with_Rama https://en.wikipedia.org/wiki/Rendezvous_with_Rama