Dem
60
Are you talking about hitting mainstream consciousness?
Because by the time the 70’s rolled around, Sc-Fi in literature was fairly popular. From sever different sci-fi mags, to short stories appearing in Playboy. By then, there had already been several heavy hitters active for decades, like Asimov, Heinlein, Dick, Clarke, Bradbury etc.
I will give you that it wasn’t probably till Star Trek, and then Star Wars, that Sci-Fi had become more mainstream with the average American.