4 inch patch.
The first phase of man's active exploration of the Moon came to an end with the Apollo 17 mission. Many questions about lunar science were answered during the intensive activity of the Apollo missions, but many more remain to be answered. Some of the unanswered questions will be answered in the future from data already returned but as yet not fully analyzed, and some will have to wait for data yet to be returned from instruments already in place on the lunar surface. Still other questions must await further exploration.
The basic objective of the Apollo 17 mission was to sample basin-rim highland material and adjacent mare material and investigate the geological evolutionary relationship between these two major units. Commander Eugene Cernan and Lunar Module Pilot Harrison Schmitt, also a professional geologist, engaged in three moon walks for a total of 22 hours and 2 minutes. The Lunar Rover also experienced its first lunar fender bender.Numerous individual investigations of surface and spatial features have been performed based on the Apollo 17 crew orbital observations and panoramic and metric camera photographs. The scope of these investigations has ranged from studies of the structure of individual craters to studies of the sequences of mare stratigraphy and mare ridges to studies of the solar corona and zodiacal light.