Overview
ISO 16691:2014 - Space systems - Thermal control coatings for spacecraft - General requirements - defines general requirements for thermal control coatings (TCC) applied to metallic and non‑metallic spacecraft surfaces and payloads. The standard specifies the intended thermo‑optical properties (notably solar absorptance, αs, and emittance, ε) and describes the role of TCCs in reducing external heat absorption and regulating radiant heat exchange between on‑board equipment and spacecraft structure. It also addresses environmental effects in space (UV/VUV, charged particles, atomic oxygen, vacuum, temperature cycling, contamination) that influence coating performance.
Key topics and requirements
- Scope and definitions: clear definitions of TCC, coating system, primer, witness sample, BOL (beginning of life) and EOL (end of life).
- Functionality and components: role of TCCs within passive and active thermal control systems and their placement relative to other thermal control materials.
- Selection guidance: criteria for choosing coatings according to mission orbit, thermal requirements, and environmental exposure.
- Test methods: standard test regimes for verifying coating quality and performance, including:
- Visual inspection, coating thickness, adhesion
- Thermo‑optical property measurement (αs and ε)
- Electrical surface/volume resistance
- Outgassing (off‑gassed products)
- UV and radiation resistance, atomic oxygen resistance
- Gloss, temperature cycling, mass of ejecta
- Application requirements: recommendations for surface preparation, coating application, curing, protectors and packing for transport/launch.
- Quality and safety: production quality assurance program, safety requirements during application, identification and record‑keeping, and procedures for changes and revisions.
- Normative references: links to related methods such as ISO 9117‑1 (drying tests) and ISO 14624‑3 (off‑gassing determination).
Practical applications and users
- Who uses ISO 16691:2014:
- Spacecraft thermal engineers and system designers
- Materials and coatings manufacturers supplying TCCs
- Coating applicators and surface‑treatment contractors
- Test laboratories performing thermal‑optical, environmental and outgassing tests
- Quality assurance, procurement and mission assurance teams
- Typical applications:
- Passive thermal control coatings on spacecraft structure, payload housings and instruments
- Surface finishes selected to achieve target αs and ε for thermal balance
- Coatings specified for low outgassing, radiation and atomic‑oxygen resilience in LEO, GEO and deep space missions
Related standards
- ISO 9117‑1:2009 - Paints and varnishes - Drying tests (referenced)
- ISO 14624‑3 - Space systems - Safety and compatibility of materials - Off‑gassing determination (referenced)
Keywords: ISO 16691:2014, thermal control coatings, TCC, spacecraft, solar absorptance, emittance, thermo‑optical properties, space environment, thermal control system.
