An Apollo Command Module Flight Direction Attitude Indicator (FDAI) '8 ball' mockup used by Apollo Mission Control Center Guidance, Navigation and Control engineers as a training tool for Apollo 7, 8, and 9. The black, white, and red ball is encased in a 5.5 x 6.25 x 5.5 acrylic holder with a reticle on the front. In fine condition, with general wear. Accompanied by a letter of provenance from Apollo GNC Neil Hutchinson, in part: "This Apollo '8-ball' was built by Frank DiGenova, a Staff Support Room flight controller in the Houston Mission Control Center. Frank was an expert in spacecraft guidance and control systems and built the device to hep train Apollo Guidance, Navigation and Control Engineers (call sign GNC) how to visualize various Apollo spacecraft attitude maneuvers. The actual spacecraft of course had real '8-balls' connected to appropriate electronics and an inertial platform as a primary instrument for the flight crews…This unique tool was used by me and other GNC flight controllers for Apollo 7, 8, and 9 and has been in my possession since Apollo 9." Inside the Command Module, the red, black, and white ‘8 ball’ was used to define the relative position of the spacecraft in three-dimensional space. While we have offered functional FDAI hardware in the past, this is the first engineering model we have encountered.
Terms and abbreviations used in our descriptions.