Overview
ISO 15889:2011 - Space data and information transfer systems - The data description language EAST specification - defines the Enhanced Ada SubseT (EAST) language for creating machine-readable descriptions of data, known as Data Description Records (DDRs). DDRs provide a complete and exact description of data formats so software tools can automatically analyse and interpret binary or textual data produced by spacecraft, ground systems, or archives on different host machines. ISO 15889:2011 is based on CCSDS 644.0‑B‑3 (June 2010) and represents the international standard for EAST in space data systems.
Key topics and technical requirements
The standard covers both the logical and physical description of data using EAST, including:
- Language definition and syntax - lexical elements, identifiers, numeric literals and formal syntax (see Annex C).
- Logical description constructs - type and subtype declarations, object declarations and the overall structure of an EAST description.
- Physical representation - representation clauses, storing arrays, storing octets/bits, and mapping between logical types and their on‑wire or on‑disk representations.
- Scalar type representation - rules for representing integers, reals and enumerations in physical form.
- Conformance and reserved keywords - requirements for conformant EAST implementations and reserved language elements.
- Supporting material - annexes with acronyms/glossary, character definitions, formal syntax, and differences between Ada and EAST.
The document requires explicit versioning of EAST descriptions and includes editorial references to ISO/IEC character set standards.
Applications
ISO 15889 is primarily applied in space data systems where precise, automated interpretation of mission data is essential:
- Creating interoperable Data Description Records (DDRs) for telemetry, telecommand responses, scientific instrument output, and archive files.
- Enabling automatic parsing and value extraction by ground segment tools, data processors, mission control systems and long‑term archives.
- Supporting cross‑platform data exchange and preservation, allowing software on different host machines to reliably interpret mission data formats.
- Facilitating software toolchains for validation, decoding, visualization and conversion of spacecraft data formats.
Who uses this standard
Typical users include:
- Spacecraft software engineers and payload instrument teams
- Mission data system architects and ground segment developers
- Data archivists, quality assurance and operations personnel
- Tool developers building DDR parsers, telemetry decoders and format validators
- Standards and systems engineers working with CCSDS/ISO space data standards
Related standards
- CCSDS 644.0‑B‑3 (The data description language EAST specification) - the originating recommended standard adopted by ISO.
- References to relevant character set standards such as ISO/IEC 8859‑1 and ISO/IEC 10646 are noted in the standard.
Keywords: ISO 15889, EAST specification, Data Description Records, DDR, space data standards, CCSDS 644.0‑B‑3, data description language, telemetry, spacecraft data interoperability.