Actually, since Mariner 4 returned its pictures of the real Mars
Historically, that is exactly when most people realized that Mars is not Eareth-like, and manned flight to Mars assumed a much much lower priority.
ep
Space/Science » in reply to NASA Has Had No Clear Goal Or Timetable For Human Spaceflight Since Apollo
Historically, that is exactly when most people realized that Mars is not Eareth-like, and manned flight to Mars assumed a much much lower priority.
ep