ISO 22670-2021 PDF

Full title and description

Space data and information transfer systems — Space link extension (SLE) — Return-channel-frames (RCF) service specification. This International Standard defines the abstract service model, operations and behaviours for the SLE RCF transfer service used to deliver telemetry frames from a master or virtual channel to a mission user.

Abstract

The document defines the SLE Return-Channel-Frames (RCF) service in conformance with the SLE Reference Model. The RCF service is an SLE transfer service that delivers all telemetry frames from one master channel or one virtual channel to a mission user. The standard specifies, in an abstract manner, the operations required to provide the service, the parameter data associated with each operation, the observable behaviours resulting from operations, and the valid sequencing and relationships of operations and behaviours. It explicitly does not define product implementations, internal system interfaces, methods or technologies for acquiring frames from spacecraft signals, communications-environment technologies, or management procedures for scheduling and controlling the service.

General information

• Status: Published (current international standard)
• Publication date: 30 June 2021
• Publisher: International Organization for Standardization (ISO)
• ICS / categories: 49.140 (Space systems and operations)
• Edition / version: Edition 3 (2021)
• Number of pages: 141

Scope

This standard defines the Space Link Extension (SLE) Return-Channel-Frames (RCF) transfer service model used to provide telemetry frames from a specified master channel or virtual channel to a mission user. It covers the abstract service operations, required parameters, resulting behaviors and valid operation sequences needed to request, deliver and manage RCF data. The scope excludes implementation-specific details, on‑board or ground‑station signal acquisition techniques, communications‑environment technologies, and operational management activities such as scheduling and mission control procedures.

Key topics and requirements

• Abstract definition of the RCF transfer service and its purpose (delivery of telemetry frames from master/virtual channel).
• Specification of service operations (e.g., start, stop, transfer, status, retrieval operations) and required parameters for each.
• Definition of behaviour and state changes resulting from operations and the valid sequencing of operations.
• Data structures and service data units necessary for RCF message exchange (abstract level).
• Interoperability requirements to align service behaviour with the SLE Reference Model.
• Conformance model: what aspects an implementation must support to claim SLE RCF compliance (abstract requirements rather than product tests).
• Explicit out-of-scope items: implementation details, frame acquisition methods, communications hardware, and operational scheduling/control procedures.
• Normative references to the SLE Reference Model and related SLE service specifications for cross-reference and consistency.

Typical use and users

Primary users include spacecraft ground-segment architects, mission operations centres, satellite operators, systems integrators, ground-station vendors and software developers implementing SLE ground-to-ground transfer services. The standard is used when designing or procuring ground systems or software components that must interoperate across agencies or organizations to transfer telemetry frames using the SLE framework. Standards bodies, test laboratories and organizations preparing interoperability agreements or memoranda of understanding (MoUs) for cross-support also use this specification.

Related standards

Key related standards and documents include the SLE Reference Model (ISO 15396) and other SLE service specifications in the ISO 2266x family (for example ISO 22669 — Return-all-frames service, and ISO 22671 — Forward CLTU service). The SLE series is closely aligned with CCSDS recommended practices and cross-support models used for agency-to-agency interoperability.

Keywords

Space Link Extension, SLE, Return-channel-frames, RCF, telemetry frames, transfer service, ISO/TC 20/SC 13, interoperability, SLE Reference Model, space data transfer.

FAQ

Q: What is this standard?

A: ISO 22670:2021 is the International Standard that specifies the Space Link Extension (SLE) Return-Channel-Frames (RCF) service — an abstract transfer-service model for delivering telemetry frames from a master channel or virtual channel to a mission user.

Q: What does it cover?

A: It covers the abstract definition of the RCF service: the operations provided, parameters for those operations, the behaviours that result from invoking operations, and the valid sequencing and relationships of operations and behaviours. It does not define product implementations, signal acquisition techniques, communications hardware, or operational scheduling procedures.

Q: Who typically uses it?

A: Users include spacecraft ground system architects, mission operations centres, satellite operators, ground-station vendors, systems integrators, software implementers of SLE services, test houses and organizations preparing cross-support agreements between agencies.

Q: Is it current or superseded?

A: ISO 22670:2021 (Edition 3) was published on 30 June 2021 and supersedes earlier editions (for example the 2013 edition). As of 28 February 2026 it is the published, current edition.

Q: Is it part of a series?

A: Yes. ISO 22670 is part of the family of SLE service specifications maintained under ISO/TC 20/SC 13 and is aligned with the SLE Reference Model (ISO 15396). Related ISO SLE documents include other service specifications such as ISO 22669 (Return-all-frames) and ISO 22671 (Forward CLTU) among others.

Q: What are the key keywords?

A: Space Link Extension (SLE), Return-channel-frames (RCF), telemetry frames, transfer service, interoperability, SLE Reference Model, ISO 15396, space data transfer.