Ion chamber
An ion chamber was a piece of advanced sensor technology aboard NASA's Mariner 2 and Ranger Block I space probes when they were launched in the mid-20th century.

Schematics of the Mariner 2 and Ranger spacecraft depicting the location of the ion chamber were stored in the 's library computer database. This database was accessed by the Talosians in 2254. ()

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Sensor technology (retconned)