What were the main reasons why the USSR and US moved to detente between 1963-1975?

Detente, the beginning of the end of the Cold War between the Soviet Union and the United Sates began in 1963 and brought the long decades of tension to a close in 1975. The motives behind the paradigm shift towards cooperation were not those that reconciled the differences between the Eastern and the Western giants, but rather those that were built upon the limited, but common desire--- peaceful coexistence. The two countries, along with other states involved …

…Apollo-Soyus mission was successfully underway and American and Soviet astronauts were giving each other 'bear hugs' in space. The road of détente was not easy to walk for it required commitment of people from very different ideological and political platforms, and yet the period of consensual rest did both countries good in terms of their domestic and foreign responsibilities. For these main reasons, was the détente set in motion.