ISO 22645:2016

Overview

ISO 22645:2016 - "Space data and information transfer systems - TM (telemetry) space data link protocol" - is an international standard (second edition, adopted from CCSDS 132.0-B-2) that defines the TM Space Data Link Protocol used for spacecraft telemetry links. The standard specifies the services offered to users, the protocol data units (PDUs) such as TM transfer frames, and the procedures that sending and receiving protocol entities perform. It documents frame structure, encoder/decoder behaviour and options including the Space Data Link Security (SDLS) option, while not prescribing specific product implementations, interface implementations, methods/technologies, or management activities.

Key topics and technical requirements

• TM transfer frame structure and headers - definition of primary/secondary headers, data field status and control fields used for telemetry frames.
• Virtual channels and master channels - services and relationships for multiplexing multiple data sources over a single physical channel (virtual channel packet service, virtual channel frame service, master channel frame service).
• Protocol Data Units (PDUs) - specification of TM frames and optional SDLS-secured frames; how PDUs are formed, encoded and interpreted.
• Sender and receiver procedures - required encoder/decoder behaviour, packet processing, multiplexing/demultiplexing logic and error-control fields.
• Managed parameters - lists of configurable parameters for physical channels, master channels and virtual channels (see sections on managed parameters).
• SDLS (Space Data Link Security) option - integration of security services for confidentiality, integrity or authentication when used.
• Service model (synchronous/asynchronous) - service assumptions from lower layers and the mapping to OSI-like functions.

Applications and who uses this standard

ISO 22645:2016 is essential for organizations designing or operating space telemetry links where interoperability, consistency and cross-support between agencies is required. Typical users include:

• Space agencies (NASA, ESA, JAXA, etc.) and mission operations centers
• Satellite manufacturers and spacecraft avionics designers
• Ground station integrators and telemetry processing facilities
• Systems engineers and mission architects defining downlink/data handling interfaces
• Software developers implementing TM frame encoders/decoders and SDLS support

Using this standard helps ensure reliable telemetry transfer, multi-vendor interoperability, predictable multiplexing of data streams (virtual channels), and optional security layering for mission-critical links.

Related standards

• CCSDS Recommended Standard: CCSDS 132.0-B-2 (basis for ISO 22645:2016)
• Other CCSDS space data link and packet transfer standards (for interoperability planning)
• ISO/TC 20/SC 13 documents on space data and information transfer systems

Keywords: ISO 22645, TM space data link protocol, telemetry protocol, space data link, CCSDS, TM transfer frame, virtual channel, SDLS, spacecraft telemetry, space communications.