ISO 12171:2002 specifies the common requirements which define the systems architecture of a spacecraft telecommand channel service. This architecture is intended to provide a common framework within which space agencies may implement compatible future spacecraft telecommanding systems.
ISO 12171:2002 establishes a layered concept for spacecraft telecommanding. Standard services are defined within each layer, and space agencies will be encouraged to develop corresponding facilities to provide these services in support of projects. Projects may also elect to be partially compatible with the concept by interfacing with the standard systems at intermediate layers within any of the service specifications.