BS ISO 22671:2021

This standard BS ISO 22671:2021 Space data and information transfer systems. Space link extension (SLE). Forward communications link transmission unit (CLTU) service specification is classified in these ICS categories:

• 49.140 Space systems and operations

This Recommended Standard defines, in an abstract manner, the Forward CLTU service in terms of:

1. the operations necessary to provide the transfer service;

2. the parameter data associated with each operation;

3. the behaviors that result from the invocation of each operation; and

4. the relationship between, and the valid sequence of, the operations and resulting behaviors.

It does not specify:

1. individual implementations or products;

2. the implementation of entities or interfaces within real systems;

3. the methods or technologies required to radiate data to a spacecraft and to acquire telemetry frames from the signals received from that spacecraft for extraction of the Operational Control Field;

4. the methods or technologies required for communications; or

5. the management activities necessary to schedule, configure, and control the Forward CLTU service.