Overview
ISO 12175:1994/Amd 1:2015 - "Space data and information transfer systems - Standard formatted data units - Structure and construction rules" defines the structure, labelling and construction rules for Standard Formatted Data Units (SFDUs) used in space data interchange. Originally prepared by the Consultative Committee for Space Data Systems (CCSDS) and amended in 2015, the standard codifies a modular, machine‑readable approach to packaging space-related digital data for open-system exchange and long‑term interoperability.
Key topics and technical requirements
- SFDU concept and purpose: establishes a uniform method to label, describe and organize data objects so they can be exchanged, referenced and interpreted across agencies and ground/space systems.
- LABEL–VALUE–OBJECT (LVO): the basic SFDU building block that pairs a standardized label with a value field and optional object content to support identification and parsing.
- Compound and simple LVOs: defines structure for simple LVOs and compound constructs such as Exchange Data Units (EDU), Application Data Units (ADU) and Description Data Units (DDU).
- Class IDs and ADIDs: classification fields (Class ID) and Authority and Description Identifiers (ADID) that link data objects to authoritative descriptions and control authorities (CAID, DDID).
- Delimitation and length control: multiple delimitation modes (length, marker patterns, EOF variants) to support streaming and file-based objects.
- Metadata and description binding: mechanisms to attach descriptive metadata (e.g., Parameter Value Language / PVL descriptions) and to reference externally defined data entities.
- ASN.1 and encoding guidance: normative ASN.1 definitions and octet/ASCII conventions for consistent binary and textual representations.
- Referencing environment: guidance for naming and referencing external labelled/unlabelled objects to enable modular data assembly.
Applications and practical value
- Mission data packaging: standardizes telemetry, science products, calibration files and ancillary data packaging for spacecraft missions.
- Interoperability and cross‑support: enables agencies (NASA, ESA, JAXA, CSA, etc.) and contractors to exchange data without bespoke translators.
- Data archiving and reuse: consistent labeling and metadata support long-term preservation, discovery and automated processing of space datasets.
- Ground systems and tools: used by spacecraft operations, science data systems, instrument teams, and mission software engineers to design I/O formats and ingestion pipelines.
Who should use this standard
- Space agency standards teams and system architects
- Mission data managers and instrument teams
- Ground segment and archive software developers
- Contractors implementing cross‑agency data exchanges
Related standards
Relevant CCSDS and ISO references include CCSDS recommendations on SFDU control authority, PVL specification, ASCII encoding and referencing environment (see CCSDS 620.x, 630.x, 641.x, 643.x, 622.x). For ASN.1 encoding rules consult ISO 8824.
Keywords: ISO 12175, SFDU, standard formatted data units, CCSDS, space data standards, data interchange, LVO, ADID, EDUs, ADUs, DDUs, ASN.1, space data interoperability.