The Apollo Guidance Computer

Perhaps the single spacecraft component that assured the success of the Apollo lunar missions was its guidance computer. Created in the 1960s when most computers filled an entire room, the Apollo Guidance Computer (AGC) was small, low power, and included capabilities that are advanced by even today’s standards. We will be discussing its hardware and software architecture, I/O devices, and how the designers overcame the demanding requirements inherent in a spacecraft computer. Additionally, we will cover the human interface, command language and operations required for a flight from the Earth to the Moon. Attendees will get the opportunity to examine an early AGC, its components and review the source code. A hardware and software emulator, running actual flight software (Apollo 13 and 14) will be used to demonstrate the Display and Keyboard user interface (attendees can bring a USB thumb drive to receive a copy of the emulator). Frank O’Brien is a volunteer Apollo historian for NASA, primarily as a contributing editor for the Apollo Lunar Surface Journal, and is co-editor of the Apollo Flight Journal. Through the use of mission transcripts, technical interviews with the flight crews and a vast collection of documentation and multimedia resources, the Apollo Journals have become the canonical resource for those interested in mankind's greatest voyage of exploration. From this work, Frank was invited to the Cradle of Aviation Museum on Long Island, New York to assist in their May, 2002 reopening. He prepared the only remaining Lunar Module Mission Simulator for exhibition, created demonstration software for a Lunar Module cockpit trainer, and prepared an Apollo space suit for the museum’s centerpiece Apollo 11 diorama. Frank is now part of a team creating a new museum, the Infoage Science/History Learning Center in Wall, NJ.