Command system

The Multimission Command (MMC) System is described. The major components within the MMC System are discussed, with the emphasis on the telecommunication-related implementations. Two versions of the spacecraft command detection system (the Viking heritage command detector and the NASA standard command detector) are discussed in detail. The former prevails in the existing flight projects and the latter will likely be adopted by the missions of the near future. The preparation of design control tables for the control of command link performance between deep space stations and the spacecraft is also discussed.