In this scene, the spacecraft is actually moving from right to left. Upon approaching the moon, the spacecraft was oriented with the service propulsion engine facing in the direction of travel. Communication with Earth was temporarily interrupted as the spacecraft swung around the far side of the moon. On their own, the crew performed the complicated procedure which fired the engine for a little over 4 minutes thereby slowing the speed of the spacecraft just enough to place it into lunar orbit. This was a critical maneuver and everyone was more than just a little tense as the engine had never been tested in lunar orbit before this mission. Any malfunctions or deviation in burn time could have lead to disastrous consequences.. Jim Lovell later stated it was the longest four minutes he had ever spent. Everyone was relieved as the engine performed flawlessly and on Christmas Eve the crew of Bill Anders, Frank Borman and Jim Lovell became the first human beings in history to orbit another celestial body other than the planet earth.