The essentials for good prophetic fiction—and hence good science-fiction—are fairly easily stated.
It takes a technically inclined mind.
That mind must be intimately acquainted with one or more technologies—and by that I mean both the branch of theoretical science and that branch's engineering applications as of today.
Imagination is a third requirement; if imagination is put first, fantasy, not science-fiction, results.
An understanding of how political and social set-ups react to technological changes must be added, for the best types of science-fiction.
George O. Smith's "Venus Equilateral" series represents an excellent progressive development of a single line of extrapolation.
George O. Smith is a radio engineer; at the time the Venus Equilateral series started, he was working on radar equipment and Army communications radio units. It was only natural that he should pick the field of communications engineering as his line for development—he was intimately acquainted with the problems and possibilities of that field, and with the past history of the art.
"QRM Interplanetary," the first of the stories, appeared in Astounding Science-Fiction to start the series; typically, it serves merely to introduce the concept of the equilateral relay station as a necessary link in interplanetary communications. But the story has been so constructed that the working out of its plot gives a good concept of the general nature of the station, and of its functioning. Still, the story is essentially simply a suggestion that interplanetary communications will require the construction of a station in space to relay messages.
The immediately following stories of the series introduce successive problems of the purely technical art; only gradually are the associated social and political reactions of the rest of that civilization of the future brought in. From the start, the author's problem has been simplified by picking a small, almost wholly isolated segment of the culture, so that only the technology itself need be discussed.
As the series develops, however, more and more the social and political effects of the developments are brought into the picture, until, in the end, practically nothing but the social-political effects remain. The final story of the series to appear in Astounding Science-Fiction was devoted entirely to the cultural, rather than technical, problems of the matter transmitter.