Initial photography by Lunar Orbiter IV began on May 11, 1967, at an orbit of 2,706 by 6,111 km with an inclination of 85.5 degrees and a period of 12 hours. Problems began almost immediately when the camera's thermal door began to respond poorly to commands to open and close, leading to fears the door could become stuck in the closed position, blocking the camera. The door was left open and extra attitude control maneuvers were made to correct for light leakage into the camera. Nevertheless, On May 13 it was discovered that light leakage was damaging some of the film and the door was tested and partially closed, only for some lens fogging to occur as a side effect of the attitudinal changes. Finally, problems with the readout drive mechanism starting and stopping from May 20 resulted in a decision to terminate the photographic portion of the mission on May 26. Nevertheless, the entire film was read and transmitted for a total of 419 high-resolution and 127 medium-resolution frames covering 99% of the Moon's near side at resolutions from 58 to 134 meters. Its mission complete, Lunar Orbiter IV was used for tracking until it crashed into the lunar surface through natural decay of its orbit by October 31.