ISO 14953:2024

Space systems - Structural design - Determination of loading levels for static qualification testing of launch vehicles

This document specifies a procedure for determining the loading level of a qualification test of a launch vehicle structure and takes into account all the minimum allowable strength characteristics necessary for these structures.

Systèmes spatiaux — Conception des structures — Détermination des niveaux de chargement pour un essai statique de qualification des véhicules lanceurs

La présente Norme internationale spécifie une procédure de détermination des niveaux de chargement pour un essai de qualification d'une structure d'un lanceur compte tenu de ses caractéristiques minimales admissibles du point de vue de la résistance. Elle sert à obtenir la résistance spécifiée nécessaire pour tous les exemplaires d'une structure fabriqués en série qui ont satisfait les critères de l'assurance produit.

General Information

• Status: Published
• Publication Date: 14-Mar-2024
• ICS: 49.140 - Space systems and operations
• Technical Committee: ISO/TC 20/SC 14 - Space systems and operations
• Drafting Committee: ISO/TC 20/SC 14 - Space systems and operations
• Current Stage: 9092 - International Standard to be revised
• Start Date: 11-Jun-2024
• Completion Date: 13-Dec-2025

Relations

• Revises: ISO 14953:2000 - Space systems - Structural design - Determination of loading levels for static qualification testing of launch vehicles
• Effective Date: 27-Aug-2022

Overview

ISO 14953:2024 is a critical international standard developed by ISO for space systems engineering, specifically focusing on the structural design of launch vehicles. This standard establishes a detailed procedure for determining loading levels in static qualification testing of launch vehicle structures. It ensures the test loads accurately reflect the minimum allowable strength characteristics necessary to verify structural integrity and mission reliability. By adhering to ISO 14953:2024, engineers and manufacturers can confidently validate the structural design against real-world service life conditions, including mechanical, thermal, and geometric factors.

Key Topics

• Qualification Test Loading Calculation
  The core of ISO 14953:2024 lies in calculating the corrected external loading (P_Q) for qualification tests. This calculation adjusts design limit loads using a corrected safety factor that incorporates various correction factors to reflect real operational variances.

• Corrected Safety Factor (J_C)
  This safety factor is a multiplicative composite considering:

  • Thickness variations (K_min)
  • Influence of adjacent structures (K_adj)
  • Thermal gradients (K_T)
  • Temperature effects on material properties (K_θ)
  • Dispersions in material and geometry (K_σ)
  • Geometric imperfections affecting buckling behavior (K_imp)

• Correction Factors
  ISO 14953:2024 defines rigorous methods to calculate and apply each correction factor, ensuring precise reflection of manufacturing tolerances, operational environment, and structural sensitivities. For instance, K_min addresses minimum manufacturing thickness in metals, while K_adj assesses test boundary condition adequacy compared to flight configurations.

• Implementation Guidance
  The standard instructs selecting the lowest corrected load among critical structure areas for qualification to ensure conservative yet realistic testing. It also allows for alternative test modes if the scenario demands, provided they are fully justified.

Applications

ISO 14953:2024 serves an essential role in the aerospace sector, particularly in the design, verification, and certification phases of launch vehicle development. Its applications include:

• Static Structural Qualification Testing
  Ensuring that launch vehicle structures withstand limit loads during qualification tests simulating flight conditions.
• Flight-Ready Structural Verification
  Validating structural integrity by accounting for real-life load variations and imperfections, reducing risk of in-service failure.
• Design Safety Assurance
  Providing standardized safety factors and correction methodologies to harmonize testing levels across different designs and manufacturers.
• Regulatory Compliance
  Supporting adherence to international aerospace standards and facilitating acceptance by national and international space agencies.

Related Standards

ISO 14953:2024 complements a suite of space systems standards, including:

• ISO 10786:2011 - Structural components and assemblies for space systems
• ISO 10795:2019 - Space systems programme management and quality vocabulary
• ISO 16454:2007 - Structural design stress analysis requirements
• ISO 24638:2021 - Pressure components and pressure system integration in space systems
• IEC 60050-192:2015 - International Electrotechnical Vocabulary on dependability, relevant for failure mode terminology

By integrating these standards, organizations can fully address mechanical, thermal, and reliability aspects critical to launch vehicle structural qualification.

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Keywords: ISO 14953:2024, launch vehicle structural design, static qualification testing, loading level determination, aerospace standards, corrected safety factor, structural integrity, space systems engineering, launch vehicle testing, qualification test loading, correction factors, structural qualification compliance.

Standards Content (Sample)

International
Standard
ISO 14953
Second edition
Space systems — Structural design
2024-03
— Determination of loading levels
for static qualification testing of
launch vehicles
Systèmes spatiaux — Conception des structures — Détermination
des niveaux de chargement pour un essai statique de qualification
des véhicules lanceurs
Reference number
© ISO 2024
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on
the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address below
or ISO’s member body in the country of the requester.
ISO copyright office
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Phone: [phone]
Email: [e-mail]
Website: www.iso.org
Published in Switzerland
ii
Contents Page
Foreword .iv
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Design of loading levels . 2
4.1 General .2
4.2 Calculation of qualification test loading .2
4.3 Corrected safety factor .2
4.4 Correction factors .3
4.4.1 Correction factor for thickness, K .3
min
4.4.2 Correction factor for adjacent structures, K .3
adj
4.4.3 Correction factor for thermal gradients, K .3
T
4.4.4 Correction factor for temperature, K .4
θ
4.4.5 Correction factor for dispersions, K .4
σ
4.4.6 Correction factor for geometric imperfections, K .4
imp
4.5 Comparison of results .5
4.6 Implementation of this document .5
Bibliography . 6

iii
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
bodies (ISO member bodies). The work of preparing International Standards is normally carried out through
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with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.
The procedures used to develop this document and those intended for its further maintenance are described
in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the different types
of ISO document should be noted. This document was drafted in accordance with the editorial rules of the
ISO/IEC Directives, Part 2 (see www.iso.org/directives).
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This document was prepared by Technical Committee ISO/TC 20, Aircraft and space vehicles, Subcommittee
SC 14, Space systems and operations.
This second edition cancels and replaces the first edition (ISO 14953:2000), which has been technically
revised.
The main changes are as follows:
— the formula for J has been changed so that all the terms are multiplicative,
C
— a new correction factor has been introduced to take into account the structure imperfections.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www.iso.org/members.html.

iv
International Standard ISO 14953:2024(en)
Space systems — Structural design — Determination of
loading levels for static qualification testing of launch
vehicles
1 Scope
This document specifies a procedure for determining the loading level of a qualification test of a launch
vehicle structure and takes into account all the minimum allowable strength characteristics necessary for
these structures.
2 Normative references
There are no normative references in this document.
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
ISO and IEC maintain terminology databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at https:// www .electropedia .org/
3.1
external loading
system of forces, moments and pressures external to a structure and applied to that structure
3.2
failure mode
manner in which failure occurs
Note 1 to entry: A failure mode may be defined by the function lost or other state transition that occurred.
Note 2 to entry: Structural failure modes include: rupture, collapse, detrimental deformation, excessive wear or any
other phenomenon resulting in an inability to sustain loads, pressures and corresponding environments, or that
jeopardizes mission success.
[SOURCE: IEC 60050-192:2015, 192-03-17, modified — Note 2 to entry has been added reflecting the
definition in ISO 10786:2011, 3.19.]
3.3
limi
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