Extremely rare Mercury Capsule Horizon Scanner manufactured by Barnes Engineering Company, measuring approximately 5.75″ tall and 5.5″ in diameter, labeled on the top, “Horizon Scanner, Serial No. 134…Part No. B4232-001, Model 13-130A-1-R1.” There is a ten-pin connector on top with a label below identifying the various functions. In very good to fine condition. The scanner was incorporated into the spacecraft to provide earth fixed reference to the Mercury astronaut in the event he had to assume manual attitude control during reentry; under nominal conditions an automatic attitude control system performed this function. An accurate determination of the horizon was considered a good human backup to orient the craft for a return from orbit should these automatic control systems fail.
Terms and abbreviations used in our descriptions.