ISO 14622:2025

International
Standard
ISO 14622
Second edition
Space systems — Structural design
2025-04
— Loads and induced environment
Systèmes spatiaux — Conception des structures — Charges et
environnement induit
Reference number
© ISO 2025
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ii
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Determination of loads and the induced environment . 4
4.1 General input data .4
4.1.1 System inputs .4
4.1.2 Excitation sources .5
4.2 Determination of loading conditions .6
4.2.1 General .6
4.2.2 Types of loads .6
4.2.3 Mechanical loads .6
4.2.4 Pressure .7
4.2.5 Thermal loads .7
4.2.6 Load cases .7
4.3 Safety factors .8
4.4 Design load cases .9
Bibliography .10

iii
Foreword
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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 14622:2000), which has been technically
revised.
The main changes are as follows:
— updates of the terms and definitions to harmonize with the other structural-related ISO documents,
— clarifications on the value of safety factors,
— A bibliography has been added.
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
Introduction
The structures of a space system have to be designed in such a way that the capacity to fulfil the mission
is ensured. During the different phases of the service life, structures are indeed submitted to a number of
mechanical and/or thermal loads which may damage materials with a number of possible consequences:
— permanent deformation that may prevent the successive operation of a mechanical function,
— rupture of secondary structures which may indirectly endanger the mission (malfunction and/or release
of dangerous debris),
— rupture of primary structures which directly lead to the loss of the mission.
The probability of such events has to be reduced to an acceptable level.
This is why the identification of the different loads both in terms of nature and intensity is of primary
importance.
In the early developments of aeronautics, aircrafts were sized against a static force equivalent to a multiple
of the gravity. This situation has soon changed to use estimations and measurements of the different loads.
Nowadays, simulations of the different physics involved allows getting accurate assessments of the main
loads and the corresponding statistical distribution.
This document describes the different types of load sources and the principle of the deterministic sizing,
where safety of factors are applied on the loads.

v
International Standard ISO 14622:2025(en)
Space systems — Structural design — Loads and induced
environment
1 Scope
This document defines the principles used to determine loads and the induced environment during the
service life of a space system and its components, taking account of the notions of probability, combined
loads, corresponding safety factors and life cycle.
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
authority
organization, institution or company responsible for the management of the development of a space system (3.13)
3.2
dynamic load
time-dependent load with deterministic or stochastic variation
3.3
environment
combination of thermal and acoustic fields applied on a structure and which, together with loads and
pressure, define the mechanical condition of the structure
Note 1 to entry: Humidity and chemical conditions are not considered in this context but should be considered for the
choice of material and or surface protection.
Note 2 to entry: Shocks are considered as loads and are thus not part of the environment.
[SOURCE: ISO 10786:2011, 3.18]
3.4
hydrostatic pressure
pressure at a level below the liquid level in the tank, which is induced by the height of liquid above this level,
plus quasi-static accelerations
3.5
launch vehicle
vehicle designed to transport payloads to space
[SOURCE: ISO 10795:2019, 3.139, modified — The preferred term "launcher" has been removed.]

3.6
limit load
maximum load, or combination of loads, which a structure or a component in a structural assembly is
expected to experience during its service life, in association with the applicable operating environments (3.3)
Note 1 to entry: Load is a generic term for thermal load, pressure, external mechanical load (force, moment, or enforced
displacement) or internal mechanical load (residual stress, pretension, or inertial load).
Note 2 to entry: The corresponding stress or strain is called limit stress or limit strain.
[SOURCE: ISO 10785:2011, 3.19, modified — “maximum expected load” has been changed to "maximum
load"; note 3 and note 4 to entry have been removed.]
3.7
maximum expected operating pressure
MEOP
highest differential pressure which a pressurized hardware item is expected to experience during its service
life and retain its functionality, in association with its applicable operating environments (3.3)
Note 1 to entry: MEOP includes the effects of temperature, peaks, relief pressures, regulator pressure, vehicle
acceleration, phase changes, transient pressure (3.17) excursions, and relief valve tolerance.
[SOURCE: ISO 24638:2021, 3.17 modified — The admitted terms have been removed; notes 2 and 3 to entry
have been deleted.]
3.8
oscillating load
vibration load
load whose amplitude or direction varies within a frequency range for which the structure dynamic
response is significant
Note 1 to entry: This load can be induced by:
— POGO effect;
— buffeting;
— vortex shedding due to ground wind;
— flutter;
— acoustic environment (3.3);
— rotation of parts;
— combustion instabilities.
3.9
proof pressure
differential pressure applied during the proof test and which is equal to the MEOP (3.7) multiplied by a proof
factor J
P
3.10
safety factor
multiplying factor to be applied to limit loads (3.6) and/or maximum expected operating pressure(MEOP) (3.7)
Note 1 to entry: The factor is defined in order to account for the statistical variations of loads and structural strength
(3.15), and inaccuracies in the knowledge of their statistical distributions.
[SOURCE: ISO 24638:2021, 3.8, modified — The preferred term "design safety factor" and the admitted terms
have been removed; the words “maximum design pressure (MDP)” have been deleted from the definition;
note 1 to entry has been added.]

3.11
service life
period of time (or number of cycles) that starts with item inspection after manufacturing and continues
through all testing, handling storage, transportation, launch operations, orbital operations, refurbishment,
retesting, re-entry or recovery from orbit, and reuse that can be required or specified for the item
[SOURCE: ISO 10786:2011, 3.56]
3.12
shock load
special type of transient load (3.16), where the load shows significant peaks and the duration of the load is
well below the typical response time of the structure
Note 1 to entry: This load can be induced by:
— shockwave phenomena;
— pyrotechnic systems;
— physical impacts by deployed appendages;
— explosions.
[SOURCE: ISO 10786: 2011, 3.57, modified — Note 1 to entry has been added.]
3.13
space system
crewed or uncrewed vehicle constructed or assembled for the purpose of manoeuvring, moving, operating,
or being placed in outer space
Note 1 to entry: A space system can be a launch vehicle a rocket, a payload,
...