Interesting report from the MIT Charles Stark Draper Laboratory entitled "R-693, Guidance System Operations Plan for Manned CM Earth Orbital Missions Using Program Skylark 1, Section 7: Erasable Memory Programs, March 1973," bound in its original blue "Apollo Guidance, Navigation and Control" softcover wrappers, 8.5″ x 11″ x .25″, describing erasable-memory programs (EMPs) designed for the guidance computer used in the command module (CMC) program Skylark 1. The report provides the names, functions, and procedures for seventeen programs, including: "Recover Angle PHI at TD," "Software Restart," "Backup Optics Variance," "DSKY Display of VHF Range During P37," "Inhibit Gimbal Lock Monitor Downmodding," "SPS Gimbal Drive Test," "Monitor Single IMU CPU," and others. In fine condition. Skylark was the Apollo Guidance Computer (AGC) software flown on the Skylab 2, Skylab 3, Skylab 4, and ASTP missions.
