In June of 1963, the Soviet Union performed an encore of the Vostok 3 and 4 missions with two manned spaceships orbiting the Earth simultaneously. However, Vostok 5 and 6 was more than a simple repetition.  Vostok 5’s objective was to beat the flight-duration record. But Vostok-6 would carrying the first woman into space.  The 26 year old Valentina Tereshkova….