What is the memory capacity of the Voyager Computer Command Subsystem?

The Voyager Computer Command Subsystem has a memory capacity of 4,096 words. Each CCS computer uses 18-bit words and non-volatile plated-wire memory, an early technology designed to retain data without continuous power.

The CCS is the spacecraft’s central controller. It decodes commands sent from Earth, detects and helps correct faults, sequences spacecraft activities, and manages antenna-pointing routines. Voyager 1 and Voyager 2 each carry redundant computer systems, and the CCS design is closely related to the computer used on NASA’s Viking orbiters.

The figure can cause confusion because the CCS includes two processors, each associated with 4,096 words of memory. Trivia references generally quote the capacity of the individual CCS computer, which is why 4,096 words is the accepted answer rather than treating the pair as a single 8,192-word memory bank.

Voyager’s computers were modest even by 1970s standards, but their reliability has been extraordinary: the probes continue operating billions of kilometres from Earth with software and hardware designed more than five decades ago.