ISO 21347:2005

Overview - ISO 21347:2005 (Space systems - Fracture and damage control)

ISO 21347:2005 defines minimum fracture control and mechanical damage control requirements for space systems. It applies to fracture‑critical items (FCIs) made from metallic, non‑metallic or composite materials and to mechanical‑damage‑critical items (MDCIs) fabricated from composites (including composite‑overwrapped pressure vessels - COPVs). The standard is intended to increase confidence in safe operation and mission success for launch vehicles, spacecraft and related hardware (first edition, 2005). It explicitly excludes the NASA Space Shuttle, the International Space Station and processing of detected defects.

Key topics and technical requirements

• Scope and terminology: Definitions for FCIs, MDCIs, COPV, MEOP (Maximum Expected Operating Pressure), MDP (Maximum Design Pressure), LBB (Leak‑Before‑Burst), VDT (Visual Damage Threshold) and related fracture‑mechanics terms.
• Fracture control requirements: Design philosophy, fracture mechanics analysis, safe‑life/damage‑tolerance approaches, proof and design safety factors, and criteria to avoid unstable crack propagation.
• Mechanical damage control: Requirements for impact protection, impact damage indicators/protectors, inspection regimes and residual strength verification for composite hardware.
• Non‑destructive evaluation (NDE): Use of NDE/NDI/NDT methods to detect and size flaws, define initial flaw size for analysis, and support inspection schedules.
• Special provisions: Guidance on COPVs (metal‑lined and nonmetal‑lined), pressure vessel definitions, and requirements for pressurized structures and other critical hardware.
• Safety classification and testing: Concepts such as limit/ultimate loads, proof pressure testing, burst strength after impact (BAI) and damage tolerance testing.

Practical applications - who uses ISO 21347

• Aerospace engineers and structural designers working on launch vehicle tanks, pressurized structures, COPVs and mission‑critical hardware.
• Systems engineers and safety/risk assessors establishing fracture control policies, inspection programs and verification plans.
• Quality, test and NDE teams developing inspection procedures, acceptance tests and proof pressure protocols.
• Procurement authorities and range safety organizations setting minimum fracture and mechanical damage control requirements for unmanned and expendable systems.

Related standards and notes

• Normative reference: ISO 14623:2003 (Space systems - Pressure vessels and pressurized structures - Design and operation).
• The standard complements agency‑specific fracture control requirements (e.g., NASA, ESA) but is not a substitute for Shuttle/ISS‑specific documents.
• Keywords: ISO 21347:2005, fracture control, mechanical damage control, space systems, COPV, fracture mechanics, damage tolerance, NDE.