John Young's "CSM Transearth Coast" star chart used during training as backup Commander for Apollo 17. The star chart, identified in the lower left as "CSM Transearth Coast, Star Chart, December 6, 1972 Launch," measures 16 x 8 and features the names of all Apollo navigation stars as well as trace lines that form the constellations used to locate and identify the stars. The chart is designed with the constellations aligned on the ecliptic, with specific stars used for Apollo navigation identified, named, and numbered with a two-digit numerical code ranging from 1 (Alpheratz) to 45 (Fomalhaut). The chart could be used to identify and locate specific stars such that an onboard optical device, the Sextant, could be used to determine the orientation of the spacecraft relative to an onboard Inertial Measurement Unit (IMU); the onboard computer (the Apollo Guidance Computer) would then calculate the location of the craft in inertial space. In fine condition, with light overall silvering and vertical streaking. Accompanied by a certificate of authenticity from Susy Young, wife of the late John Young, certifying that this chart "was used in training for the Apollo 17 mission to the Moon December 7-19, 1972. It has been a part of the John W. Young collection since that time."
Although the Apollo 15 prime crew originally received the backup assignment for Apollo 17, they were replaced after the postage stamp incident came to light in early 1972. Fresh from walking on the moon on Apollo 16, John Young and Charlie Duke received the respective backup assignments of Commander and Lunar Module Pilot, while Apollo 14 CMP Stu Roosa served as backup Command Module Pilot. Although the Apollo 17 prime crew was able to make the journey as scheduled, Young would fly in space twice more—as Commander of the STS-1 and STS-9 Space Shuttle missions.
