ISO 11227:2012

INTERNATIONAL ISO
STANDARD 11227
First edition
2012-09-15
Space systems — Test procedure to
evaluate spacecraft material ejecta upon
hypervelocity impact
Systèmes spatiaux — Mode opératoire d’essai pour l’évaluation des
éjectats de matériaux des véhicules spatiaux résultant d’impacts à
hypervitesse
Reference number
©
ISO 2012
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ii © ISO 2012 – All rights reserved

Contents Page
Foreword .iv
Introduction . v
1 Scope . 1
2 Normative references . 1
3 Terms, definitions, abbreviated terms and symbols . 1
3.1 Terms and definitions . 1
3.2 Abbreviated terms . 3
3.3 Symbols . 3
4 General requirements . 3
5 Calibration . 4
5.1 General . 4
5.2 Impact parameters . 4
5.3 General environment . 4
5.4 Ejecta characterization . 5
5.5 Report of calibration tests . 5
6 Experimental procedure . 5
6.1 General . 5
6.2 Impact parameters . 5
6.3 General environment . 6
6.4 Ejecta characterization and evaluation . 6
6.5 Additional tests . 7
6.6 Analysis of test results . 7
7 Reporting of test results . 8
7.1 General . 8
7.2 Report of testing of materials . 8
7.3 Database . 9
8 Quality assurance . 9
8.1 General . 9
8.2 Quality requirements . 9
Annex A (informative) Characterization of material ejected upon impact (ejecta) . 11
Annex B (informative) Example of an ejecta model .13
Annex C (informative) Ejecta measurement methods .16
Annex D (informative) Example of a data sheet .20
Annex E (informative) Technical data .22
Bibliography .23
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 11227 was prepared by Technical Committee ISO/TC 20, Aircraft and space vehicles, Subcommittee
SC 14, Space systems and operations.
iv © ISO 2012 – All rights reserved

Introduction
Throughout its orbit lifetime, any spacecraft is exposed to the risk of collision with man-made space debris
and natural micrometeoroids. Concentration of natural particles is nearly stable, but the amount of man-made
debris is likely to increase over time. Details concerning this space environment can be found in the documents
cited in the bibliography (see References [1] and [2]).
Damage caused by meteoroids or debris can result in total or partial mission failure and in a potential generation
of small debris. Because of the large collision velocities (hypervelocity domain), even a small object produces
upon impact a large amount of small particles, which are called ejecta. Ejecta can damage parts of the spacecraft
itself and increase the population of space debris. The orbital lifetime of the ejecta depends on several factors
such as size, initial velocity, and orbit altitude of the parent body. This population of space debris is already
[3][4][5]
evaluated at a few percent of the total space debris population and it is likely to increase in the future . It is
therefore necessary, for the mitigation of such particles, to assess the mechanism of their production.
[6][7][8]
As shown by previous experimental studies , the amount of ejecta depends primarily on the type of
material exposed directly to the space environment. It is greater for brittle materials than for ductile materials;
it depends also on the size and on the velocity of impacting particles. Consequently, the best approach for
assessing the process is to perform laboratory impact simulation using hypervelocity launchers.
The purpose of this International Standard is to describe a standard approach for assessing the behaviour,
under orbital debris or meteoroid hypervelocity impacts, of the materials that are used on the external surfaces
[9]
of spacecraft .
Results obtained from the standard tests carried out on as wide a range of materials as possible will be stored
in a database created for this purpose, or incorporated into an existing one such as ECSS-Q70-71A (see
Annex D and Reference [10]). This database will help designers choose spacecraft outer materials that mitigate
the risk of space debris.
INTERNATIONAL STANDARD ISO 11227:2012(E)
Space systems — Test procedure to evaluate spacecraft
material ejecta upon hypervelocity impact
1 Scope
This International Standard describes an experimental procedure for assessing the behaviour, under orbital
debris or meteoroid impacts, of materials that are intended to be used on the external surfaces of spacecraft and
launch vehicle orbital stages. This International Standard provides a unified method by which to rank materials.
The ejecta production characteristics of different materials are compared under standardized conditions in
which test parameters are fixed to one number. Optional tests with different parameters are also useful for the
proper selection of materials in other conditions, and they could be performed as research items.
This International Standard establishes the requirements to be satisfied for the test methods in order to
characterize the amount of ejecta produced when a surface material is impacted by a hypervelocity projectile.
Its purpose is to evaluate the ratio of ejecta total mass to projectile mass, and the size distribution of the
fragments. These are the necessary inputs for modelling the amount of impact ejecta that a surface material
might release during its orbital lifetime, thereby helping to assess its suitability for space use while mitigating
the production of small space debris.
The purpose of this International Standard is to provide data that need to be taken into account in the selection
of outer spacecraft materials, though the selection is not based on these criteria alone.
The experimental procedure defines
— the type of facility to be used,
— the size, velocity and type of projectile to be used,
— the evaluation of impact ejecta released,
— the reporting of test results, and
— the quality requirements to be used.
It is anticipated that this International Standard will be the first of several test procedure standards aimed at
characterizing the release of small debris from the external surfaces of spacecraft and launch vehicle orbital
stages as the result of interaction with the space environment. It is applicable to spacecraft and launch vehicles
operating in all types of Earth orbits.
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 24113, Space systems — Space debris mitigation requirements
3 Terms, definitions, abbreviated terms and symbols
3.1 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 24113 and the following apply.
3.1.1
brittle material
material that breaks due to a propagation defect under the action of a stress
3.1.2
ductile material
material that can be plastically deformed without breaking under the action of a stress
3.1.3
ejecta cone
shaped spray of fine particles, comprising fragments and spalls that are released during a high-velocity impact.
3.1.4
fragmentation
process by which an orbiting space object dissociates and produces debris, such as break-up, exposure to
space environment, and ageing
3.1.5
hypervelocity impact
impact occurring with a velocity greater than the velocity of sound in any given material
3.1.6
impact crater
damage left on a material, generally hemispherical in shape, after a projectile has hit its surface without going
throughout the material
3.1.7
light gas gun
LGG
experimental device consisting of a powder gun that compresses a low-density gas to accelerate a projectile
up to hypervelocities
3.1.8
meteoroid
particles of natural origin, resulting from the disintegration and fragmentation of comets and asteroids, which
orbit the sun
3.1.9
perforation
hole created by an impact on a thin material in which there is no formation of a crater
3.1.10
plasma gun
experimental device that produces an accelerated plasma flow, which is compressed in a coil and then drags
...