 At 64 hours into the flight , the crew began to prepare for Lunar Orbit Insertion @-@ 1 ( LOI @-@ 1 ) . This maneuver had to be performed perfectly , and due to orbital mechanics had to be on the far side of the Moon , out of contact with the Earth . After Mission Control was polled for a " go / no go " decision , the crew was told at 68 hours , they were Go and " riding the best bird we can find " . At 68 hours and 58 minutes , the spacecraft went behind the Moon and out of radio contact with the Earth . 
