In 1967, Robert J Van De Graaff, U.S. nuclear physicist, died at age 65.
He developed a high-voltage electrostatic generator (later called the Van de Graaff generator). You’ll remember it from your local science museum. It is the metal ball that you put your hands on and then your hair stands on end.
In 1989, the USSR announced a plan for a 2-year manned mission to Mars.
This is just one event over the years in the mission to go to Mars.