So has any human ever seen the far side of moon? I guess, not ! Because this side of the moon always stays away from us. First directly observed by human eyes when the Apollo 8 mission orbited the Moon in 1968. It includes the largest known impact feature in the Solar System: the South Pole-Aitken basin. A good sight for putting radio telescopes !
The Moon now rotates once as it orbits the Earth, allowing for the same side to always face the Earth so that the far side remains a mystery to any Earth-bound observer.
Resources / Read on the web
NASA to put man on far side of moon
Lunar and Planetary Institute
Far side of moon movie (2005)