ISO 21347:2025

Overview

ISO 21347:2025 - Space systems - Fracture and damage control - defines uniform, minimum fracture control and mechanical damage control requirements for space hardware. The second edition updates and harmonizes terminology and requirements for applying fracture-control technology to fracture‑critical items (FCIs) and mechanical‑damage‑critical items (MDCIs), including metallic, non‑metallic and composite components. It is applicable to launch vehicles, spacecraft, ground support equipment, and, with modification, reusable launch vehicles (RLVs). The standard is not applicable where project‑specific fracture/damage requirements already exist, nor to the processing of detected defects.

Key topics and technical requirements

• FCI classification: Establishes how to classify fracture‑critical items so that risk and mitigation efforts are focused appropriately.
• Fracture control plan: Requires documented plans covering design philosophy, material selection, fabrication, inspection and verification strategies.
• Damage tolerance requirements: Defines the use of damage‑tolerance life analyses and tests to demonstrate safe operation in the presence of flaws.
• MDCI classification & mechanical damage control plan: Sets requirements specific to composite items prone to impact or mechanical damage (notably COPVs - composite‑overwrapped pressure vessels).
• Non‑destructive evaluation (NDE): Specifies NDE scope and traceability needed to support fracture and damage control.
• Special demonstrations: Includes provisions for leak‑before‑burst (LBB) demonstrations, non‑FCI justification, and other special requirements.
• Traceability & documentation: Emphasizes records, material traceability and quality assurance to support structural integrity through design, manufacture and operation.
• Informative guidance: Annex A provides fracture control implementation guidance; Annex B focuses on mechanical damage control for COPVs.

Applications and users

ISO 21347:2025 is intended for:

• Aerospace engineers and structural designers developing space systems, propulsion tanks and pressure components.
• Qualification, safety and mission assurance teams responsible for fracture‑critical hardware.
• Test engineers performing damage tolerance testing, NDE, and LBB assessments.
• Program managers and procurement authorities specifying minimal fracture/damage control requirements for contractors and suppliers.

Practical uses include qualifying tankage, pressure vessels, structural assemblies and composite components to reduce risk of catastrophic failure, improve mission success, and meet range or crew‑safety requirements.

Related standards

Normative and related references cited in ISO 21347:2025 include:

• ISO 10786 (Structural components and assemblies)
• ISO 14623 (Pressure vessels - Design and operation)
• ISO 21648 (Flywheel module design and testing)
• ISO 24638 (Pressure components and pressure system integration)

Keywords: ISO 21347:2025, fracture control, damage control, space systems, FCI, MDCI, COPV, damage tolerance, NDE, launch vehicle, spacecraft.