Desirable Apollo-era early developmental example of an Emergency Detection System (EDS) Angle of Attack Sensor System, commonly called the Q-Ball, measuring approximately 14" tall and 13.25" in diameter across the base, with a NASA George C. Marshall Space Flight Center label applied on the base: "EDS Q-Ball Angle of Attack Sensor, Assy No. 50M12419-1, Contr. No. NAS 8-15686, Serial No. 9, Accept Date 1/66, Wt (Lb) 25.62, Mfd by Chrysler Corp. Huntsville." Also hand-etched with additional part numbers.
Although the mature version of the Apollo Q-Ball that ultimately flew on the manned flights was of a different design under a different contract, this piece represents early developmental work toward that end. This sensor was fabricated as part of research and development contract awarded by Marshall Space Flight Center to Chrysler. A chief difference between this and the final version is the number of ports on the top: this unit has four, while the flight version had eight. Pressure changes are measured through these ports, and then used to compute aerodynamic incidence angle and dynamic pressure data. This data helped to determine whether or not the rocket was flying on course, and allowed the flight computer to make minor corrections to the trajectory. As a part of the emergency detection system, it also relayed critical data in the event of a launch abort.
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