scope:

NEN-EN 16603-50-04 specifies the data structures and protocols for a telecommand space data link and the procedure for physical layer operation. Usually, the source of data on a telecommand space data link is located on the ground and the receiver is located in space. However, the Standard may also be used for space-to-space telecommand data links. Further provisions and guidance on the application of this standard can be found, respectively, in the following documents: • The higher level standard ECSS-E-ST-50 "Communications", which defines the principle characteristics of communication protocols and related services for all communication layers relevant for space communication (physical- to application-layer), and their basic relationship to each other. • The handbook ECSS-E-HB-50 "Communications guidelines", which provides information about specific implementation characteristics of these protocols in order to support the choice of a certain communications profile for the specific requirements of a space mission. Users of this present standard are invited to consult these documents before taking decisions on the implementation of the present one. This standard may be tailored for the specific characteristics and constraints of a space project in conformance with ECSS-S-ST-00.