- In the 1960s, NASA proposed a manned fly-by of Mars using existing Apollo hardware. The problem was there was too much weight in fuel to make it feasible. The badass physics solution: Fly around Venus and use it as a gravity assist. http://news.discovery.com/space/history-of-space/nasas-1960s-studies-for-a-manned-mars-flyby-130304.htm 8 comments space