ISO 10786:2011

Space systems — Structural components and assemblies

ISO 10786:2011 establishes requirements for the design; material selection and characterization; fabrication; testing and inspection of all structural items in space systems, including expendable and reusable launch vehicles, satellites and their payloads. When implemented for a particular space system, it will assure high confidence in achieving safe and reliable operation in all phases of its planned mission. ISO 10786:2011 applies specifically to all structural items, including fracture-critical hardware used in space systems during all phases of the mission, with the following exceptions: adaptive structures, engines and thermal protection systems.

Systèmes spatiaux — Composants et assemblages de structure

General Information

• Status: Published
• Publication Date: 07-Jul-2011
• 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/WG 1 - Design engineering and production
• Current Stage: 9092 - International Standard to be revised
• Completion Date: 24-Aug-2022

Standards Content (Sample)

INTERNATIONAL ISO
STANDARD 10786
First edition
2011-07-15
Space systems — Structural components
and assemblies
Systèmes spatiaux — Composants et assemblages de structure
Reference number
ISO 10786:2011(E)
ISO 2011
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ISO 10786:2011(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2011

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Published in Switzerland
ii © ISO 2011 – All rights reserved
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ISO 10786:2011(E)
Contents Page

Foreword ............................................................................................................................................................iv

Introduction.........................................................................................................................................................v

1 Scope......................................................................................................................................................1

2 Normative references............................................................................................................................1

3 Terms and definitions ...........................................................................................................................2

4 Symbols and abbreviated terms ........................................................................................................11

5 Tailoring................................................................................................................................................13

6 Requirements.......................................................................................................................................13

6.1 General .................................................................................................................................................13

6.2 Design requirements...........................................................................................................................13

6.3 Material requirements .........................................................................................................................18

6.4 Manufacturing and interfaces requirements ....................................................................................21

6.5 Quality assurance................................................................................................................................23

6.6 Traceability...........................................................................................................................................25

6.7 Deliverables .........................................................................................................................................25

6.8 In-service requirements......................................................................................................................26

6.9 Maintenance requirements.................................................................................................................26

6.10 Repair and refurbishment...................................................................................................................28

7 Verification of general requirements.................................................................................................28

7.1 General .................................................................................................................................................28

7.2 Verification of design requirements ..................................................................................................29

7.3 Acceptance tests .................................................................................................................................39

7.4 Qualification progamme (qualification tests) ...................................................................................40

8 Special structural items......................................................................................................................42

8.1 General .................................................................................................................................................42

8.2 Special structural items with published standards .........................................................................42

8.3 Special structural items without published standards....................................................................42

9 Documentation requirements.............................................................................................................43

9.1 Interface control documents ..............................................................................................................43

9.2 Applicable (contractual) documents .................................................................................................44

9.3 Analysis reports ..................................................................................................................................44

10 Data exchange .....................................................................................................................................46

10.1 Data set requirements.........................................................................................................................46

10.2 System configuration data .................................................................................................................46

10.3 Data exchange between design and structural analysis.................................................................46

10.4 Data exchange between structural design and manufacturing......................................................46

10.5 Data exchange with other subsystems.............................................................................................47

10.6 Tests and structural analysis.............................................................................................................47

10.7 Structural mathematical models........................................................................................................47

Annex A (informative) Recommended best practices for structural design ..............................................48

Annex B (informative) Design requirements verification methods..............................................................58

Annex C (informative) Design requirements verification methods..............................................................61

Annex D (informative) Margin of safety for combined loads........................................................................64

Bibliography......................................................................................................................................................65

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ISO 10786:2011(E)
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 ISO

technical committees. Each member body interested in a subject for which a technical committee has been

established has the right to be represented on that committee. International organizations, governmental and

non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the

International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.

International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.

The main task of technical committees is to prepare International Standards. Draft International Standards

adopted by the technical committees are circulated to the member bodies for voting. Publication as an

International Standard requires approval by at least 75 % of the member bodies casting a vote.

Attention is drawn to the possibility that some of the elements of this document may be the subject of patent

rights. ISO shall not be held responsible for identifying any or all such patent rights.

ISO 10786 was prepared by Technical Committee ISO/TC 20, Aircraft and space vehicles, Subcommittee

SC 14, Space systems and operations.
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ISO 10786:2011(E)
Introduction

Structures are the backbones of all spaceflight systems. A structural failure could cause the loss of human

lives for manned space systems or could jeopardize the intended mission for unmanned space systems.

Currently, there is no International Standard that covers all the aspects that can be used for spaceflight

structural items such as spacecraft platforms, interstage adaptors, launch vehicle buses and rocket motor

cases.

The purpose of this International Standard is to establish general requirements for structures. It provides the

uniform requirements necessary to minimize the duplication of effort and the differences between approaches

taken by the participating nations and their commercial space communities in developing structures. In

addition, the use of agreed-upon standards will facilitate cooperation and communication among space

progammes.
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INTERNATIONAL STANDARD ISO 10786:2011(E)
Space systems — Structural components and assemblies
1 Scope

This International Standard establishes requirements for the design; material selection and characterization;

fabrication; testing and inspection of all structural items in space systems, including expendable and reusable

launch vehicles, satellites and their payloads. This International Standard, when implemented for a particular

space system, will assure high confidence in achieving safe and reliable operation in all phases of its planned

mission.

This International Standard applies specifically to all structural items, including fracture-critical hardware used

in space systems during all phases of the mission, with the following exceptions: adaptive structures, engines

and thermal protection systems.
2 Normative references

The following referenced documents are indispensable for the application of this document. For dated

references, only the edition cited applies. For undated references, the latest edition of the referenced

document (including any amendments) applies.
ISO 14622:2000, Space systems —Structural design — Loads and induced environment

ISO 14623:2003, Space systems — Pressure vessels and pressurized structures — Design and operation

ISO 14953:2000, Space systems — Structural design — Determination of loading levels for static qualification

testing of launch vehicles

ISO 14954:2005, Space systems — Dynamic and static analysis — Exchange of mathematical models

ISO 15864:2004, Space systems — General test methods for space craft, subsystems and units

ISO 16454:2007, Space systems — Structural design — Stress analysis requirements
ISO 21347:2005, Space systems — Fracture and damage control
ISO 21648:2008, Space systems – Flywheel module design and testing
ISO 22010:2007, Space systems — Mass properties control

ISO 24638:2008, Space systems — Pressure components and pressure system integration

ISO 24917:2010, Space systems — General test requirements for launch vehicles
MIL-STD-1540, Revision D Test Requirements for Space Vehicles
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ISO 10786:2011(E)
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1
A-basis allowable
A-basis design allowable
A-value

mechanical strength value above which at least 99 % of the population of values is expected to fall, with a

confidence level of 95 %
[ISO 16454:2007]
3.2
acceptance test

required formal test conducted on flight hardware to ascertain that the materials, manufacturing processes,

and workmanship meet specifications and that the hardware is acceptable for intended usage

[ISO 14623:2003]
3.3
adaptive structures

autonomous structural systems which incorporate sensors, processors, and actuators to enable adaptation to

changing environmental conditions, thereby enhancing safety, stability, vibration damping, acoustic noise

suppression, aerodynamic performance and optimization, pointing accuracy, load redistribution, damage

response, structural integrity, etc.
3.4
allowable load

maximum load that can be accommodated by a structure or a component of a structural assembly without

potential rupture, collapse, or detrimental deformation in a given environment

NOTE 1 “Allowable loads” commonly correspond to the statistically based ultimate strength, buckling strength, and

yield strength, or maximum strain (for ductile materials).
NOTE 2 “Allowable load” is often referred to as just “allowable”.
3.5
assembly
combination of parts, components and units which forms a functional entity
3.6
B-basis allowable
B-basis design allowable
B-value

mechanical strength value above which at least 90 % of the population of values is expected to fall, with a

confidence level of 95 %
[ISO 16454:2007]
3.7
buckling

failure mode in which an infinitesimal increase in the load could lead to sudden collapse or detrimental

deformation of a structure
EXAMPLE Snapping of slender beams, columns, struts and thin-wall shells.
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ISO 10786:2011(E)
3.8
catastrophic failure

failure which results in the loss of human life, mission or a major ground facility, or long-term detrimental

environmental effects
3.9
collapse

failure mode induced by quasi-static loads (compression, shear or combined stress) accompanied by

irreversible loss of load-carrying capability
3.10
composite material
combination of materials different in composition or form on a macro scale
NOTE 1 The constituents retain their identities in the composite.

NOTE 2 The constituents can normally be physically identified, and there is an interface between them.

[ISO 16454:2007]
EXAMPLE Composites include
⎯ fibrous (composed of fibres, usually in a matrix),
⎯ laminar (layers of materials), and
⎯ hybrid (combination of fibrous and laminar).
3.11
composite overwrapped pressure vessel
COPV

pressure vessel with a fibre-based composite system fully or partially encapsulating a liner

NOTE The liner serves as a liquid or gas permeation barrier and may or may not carry substantial pressure loads.

The composite overwraps generally carry pressure and environmental loads.
[ISO 14623:2003]
3.12
composite structure
structural components that are made of composite materials
3.13
damage tolerance

ability of a structure or a component of a structural assembly to resist failure due to the presence of flaws,

cracks, or other damage for a specified period of unrepaired usage
[ISO 21347:2005]
3.14
design parameter

physical feature which influences the design performance of the design of structural items

NOTE According to the nature of the design variables, different design problems can be identified such as:

⎯ structural sizing for the dimensioning of beams, shells, etc.;
⎯ shape optimization;
⎯ material selection;
⎯ structural topology.
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ISO 10786:2011(E)
3.15
design safety factor

factor by which limit loads are multiplied in order to account for uncertainties and variations that cannot be

analysed or accounted for explicitly in a rational manner

NOTE Design safety factor is sometimes referred to as design factor of safety, factor of safety or just safety factor.

3.16
detrimental deformation

structural deformation, deflection or displacement that prevents any portion of the structure or some other

system from performing its intended function or that jeopardizes mission success
3.17
development test

test to provide information that can be used to check the validity of analytic techniques and assumed design

parameters, uncover unexpected system response characteristics, evaluate design changes, determine

interface compatibility, prove qualification and acceptance procedures and techniques, check manufacturing

technology, or establish accept/reject criteria
[ISO 16454:2007]
3.18
dynamic load
time-dependent load with deterministic or stochastic variation
3.19
failure mode

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

NOTE This definition applies to structural failure.
3.20
fail-safe structure

structural item for which it can be shown by analysis or test that, as a result of structural redundancy, the

structure remaining after the failure of any element of the structural item can sustain the redistributed limit load,

with an ultimate safety factor of 1,0
[ISO 21347:2005]
3.21
fatigue life

number of cycles of stress or strain of a specified character that a given structure or component of a structural

assembly can sustain (without the presence of flaw) before failure of a specified nature could occur

3.22
failure mode effects and critically analysis
FMECA

analysis performed to systematically evaluate the potential effect of each functional or hardware failure on

mission success, personnel and system safety, system performance, maintainability and maintenance

requirements
NOTE It is also used to rank by the severity of its effect.
3.23
flaw
local discontinuity in a structural material

EXAMPLES Crack, cut, scratch, void, delamination disbond, impact damage and other kinds of mechanical damage.

[ISO 21347:2005]
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ISO 10786:2011(E)
3.24
fracture control

application of design philosophy, analysis methods, manufacturing technology, verification methodology,

quality assurance, including non-destructive evaluation (NDE) and operating procedures to prevent premature

structural failure caused by the presence and/or propagation of flaws during fabrication, testing, transportation,

handling, and service events such as launch, in-orbit operation, and return
3.25
fracture-critical item
fracture-critical part

structural part whose failure due to the presence of a flaw would result in a catastrophic failure

3.26
full scale article

full-size test article which represents the whole flight structure or a part of the flight structure with

representative loading and boundary conditions
3.27
hydrogen embrittlement

mechanical-environmental process that results from the initial presence or absorption of excessive amounts of

hydrogen in metals, usually in combination with residual or applied tensile stresses

[ISO 14623:2003]
3.28
human vibration
vibration transmitted to and/or induced by the crew members
3.29
life factor

coefficient by which the number of cycles or time is multiplied in order to account for uncertainties in the

statistical distribution of loads and cycles, as well as uncertainties of the methodology used in the life related

analyses

NOTE 1 Life factor and scatter factor are interchangeable terms in some documents.

NOTE 2 Life factor is sometimes referred to as scatter factor when uncertainties are material uncertainties.

EXAMPLE Factors used in fatigue (life) analysis and damage tolerance life (crack growth safe-life) analysis.

3.30
limit load

maximum expected 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

NOTE 1 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 The corresponding stress or strain is called limit stress or limit strain.

NOTE 3 Limit load is sometimes referred to as design limit load. See informative Annex A.

3.31
loading case
combined loading case

particular condition of single (or combined) mechanical load, pressure and temperature, which can occur for

some structural components or a structural assembly at the same time during their service life

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ISO 10786:2011(E)
3.32
loading spectrum

representation of the cumulative loading levels and associated cycles anticipated for the structure or

component of a structural assembly according to its service life under all expected operating environments

NOTE Significant transportation, test, and handling loads are included in this definition.

3.33
margin of safety

measure of a structure's predicted reserve strength in excess of the design criteria

NOTE 1 For a single loading condition, MS is expressed as:

MS = { [Allowable Load (Yield or Ultimate)] / [Limit Load x Factor of Safety (Yield or Ultimate)]} -1

NOTE 2 Load may mean force, stress, or strain, if the load-stress relationship is linear.

NOTE 3 The relation also can be expressed for a combined loading case, when the load-stress relationship remains

linear for all the contributors of the loading case. Also see alternative methods in Annex D.

3.34
mass and inertia properties

mass and inertia properties of a structure comprise its mass, the location of its centre of gravity, its moments

and products of inertia, and, where applicable, its balancing masses
3.35
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

NOTE 1 MEOP includes the effects of temperature, transient peaks, relief pressures, regulator pressure, vehicle

acceleration, phase changes, transient pressure excursions, and relief valve tolerance.

NOTE 2 Some particular project may replace MEOP by Maximum Design Pressure (MDP), which takes into account

more conservative conditions.
3.36
metallic structural item
structural item made of metals

NOTE In this document, load bearing metallic liners of COPVs are also referred to as metallic structural items.

3.37
moving mechanical assembly
MMA

mechanical or electromechanical device that controls the movement of one mechanical part of a vehicle

relative to another part

EXAMPLES Gimbals, actuators, despin and separation mechanisms, motors, latches, clutch springs, dampers, or

bearings.
3.38
POGO

instability due to the coupling between the vehicle axial motion and the dynamic response characteristic of the

propulsion system
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ISO 10786:2011(E)
3.39
pressure component

component in a pressurized system, other than a pressure vessel, pressurized structure that is designed

largely by the internal pressure
[ISO 24638:2008]
EXAMPLES Valves, pumps, lines, fittings, hoses and bellows.
3.40
pressure vessel

container designed primarily for storage of pressurized fluid that (1) contains gas or liquid with an energy level

of 19,310 joules (14,240 foot-pounds) or greater, based on adiabatic expansion of a perfect gas; or (2)

contains gas or liquid that will create a mishap (accident) if released; or (3) will experience a MEOP greater

than 700 kPa (100 psi)

NOTE Pressurized structures, pressure components and pressurized equipment are excluded from this definition.

3.41
pressurized equipment
special pressurized equipment

piece of equipment that meets the pressure vessel definition, but for which it is not feasible or cost effective to

comply with the requirements applicable to pressure vessels
EXAMPLES Batteries, heat pipes, cryostats and sealed containers.
3.42
pressurized hardware

pressurized hardware includes pressure vessels, pressurized structures, pressure components and

pressurized equipment
3.43
pressurized structure
structure designed to carry both internal pressure and vehicle structural loads
[ISO 14623:2003], [ISO 24638:2008]

EXAMPLES Main propellant tanks and solid rocket motor cases of launch vehicles, and crew cabins of manned

modules.
3.44
primary structure

part of a structure that carries the main flight loads and defines the overall stiffness of the structure, thus

influencing its natural frequencies and mode shapes
3.45
proof factor

multiplying factor applied to the limit load or MEOP to obtain proof load or proof pressure for use in the

acceptance testing
3.46
protoqualification test

test of the flight-quality article to a higher load level and duration than the acceptance test applied to flight

units under prototype qualification strategy

NOTE The testing consists of the same types and sequences as used in qualification testing.

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ISO 10786:2011(E)
3.47
qualification test

required formal contractual test conducted at load levels and durations to demonstrate that the design,

manufacturing, and assembly of flight-quality structures have resulted in hardware that conforms to

specification requirements

NOTE In addition, the qualification test may validate the planned acceptance progamme including test techniques,

procedures, equipment, instrumentation, and software.
3.48
random load

vibrating load or fluctuating load whose instantaneous magnitudes are specified only by probability distribution

functions giving the probable fraction of the total time that the instantaneous magnitude lies within a specified

range
NOTE A random load contains non-periodic or quasi-periodic constituents.
3.49
residual strength

maximum value of load and/or pressure (stress) that a flawed or damaged structural item is capable of

sustaining without further damage or collapse, considering appropriate environmental conditions

3.50
residual stress

stress that remains in a structure after processing, fabrication, assembly, testing or operation

EXAMPLE Welding-induced residual stress.
[ISO 14623:2003]
3.51
S-basis allowable

mechanical strength value specified as a minimum by the governing industrial specification, or a particular

contractor's specification

EXAMPLES Properties given in MMPDS (Metallic Materials Properties Development and Standardization).

3.52
safe life

(1) design criterion under which failure does not occur in the expected environment during the service life

(2) required period during which a structural item, even containing the largest undetected flaw, is shown by

analysis or testing not to fail catastrophically under the expected service load and environment

NOTE 1 An equivalent definition is “period during which the structure is predicted not to fail in the expected service life

environment”.
NOTE 2 Safe life is also referred as damage tolerance life or fatigue life.
3.53
safe-life structure
structure designed according to the safe-life design criterion
3.54
scatter factor

coefficient by which the number of cycles or time defined in service life is multiplied in order to account for

uncertainties in material properties when performing fatigue and/or crack growth analysis

NOTE Scatter factor is sometimes referred to as life factor, which is usually used for just the difference in material

data used in the analysis; for example, S-N data used in fatigue life analysis, or da/dN data used in crack grow analysis.

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ISO 10786:2011(E)
3.55
secondary structure

structure attached to the primary structure with negligible participation in the main load transfer and overall

stiffness
3.56
service life

period of time (or 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
3.57
shock load

special type of transient load, where the load shows significant peaks and the duration of the load is well

below the typical response time of the structure
3.58
stiffness
ratio between an applied force and the resulting displacement
3.59
stress-corrosion cracking

mechanically and environmentally induced failure process in which sustained stress and chemical attack

combine to initiate and/or propagate a crack or a crack-like flaw in a metal part

[ISO 21347:2005]
3.60
stress-rupture life

minimum time during which a non-metallic structural item maintains structural integrity, considering the

combined effects of stress level(s), time at stress level(s), and associated environments

3.61
structural component

mechanical part(s) in a functional hardware item designed to sustain load and/or pressure or maintain

alignment
EXAMPLES Antenna support structure, instr
...