ISO/FDIS 23020

FINAL
INTERNATIONAL ISO/FDIS
DRAFT
STANDARD 23020
ISO/TC 20/SC 14
Space systems — Determination of
Secretariat: ANSI
test methods to characterize material
Voting begins on:
2021­06­09 or component properties required for
break-up models used for Earth re-
Voting terminates on:
2021­08­04
entry
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Reference number
BEING ACCEPTABLE FOR INDUSTRIAL, TECHNO­
ISO/FDIS 23020:2021(E)
LOGICAL, COMMERCIAL AND USER PURPOSES,
DRAFT INTERNATIONAL STANDARDS MAY ON
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DARDS TO WHICH REFERENCE MAY BE MADE IN
NATIONAL REGULATIONS. ISO 2021
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ISO/FDIS 23020:2021(E)
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© ISO 2021

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

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

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

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

3 Terms, definitions and abbreviated terms ................................................................................................................................ 1

3.1 Terms and definitions ....................................................................................................................................................................... 1

3.2 Abbreviated terms ............................................................................................................................................................................... 5

4 Methodology of material characterization................................................................................................................................ 5

4.1 General ........................................................................................................................................................................................................... 5

4.2 Temperature range .............................................................................................................................................................................. 5

4.3 Type of tests .............................................................................................................................................................................................. 6

4.4 Test conditions ........................................................................................................................................................................................ 6

4.5 Mechanisms of degradation ......................................................................................................................................................... 7

5 Definition of the elementary tests...................................................................................................................................................... 7

5.1 General ........................................................................................................................................................................................................... 7

5.2 List of the elementary tests .......................................................................................................................................................... 8

5.3 Composite materials specifications ...................................................................................................................................... 9

6 Metallic and metallic composite materials ............................................................................................................................... 9

6.1 Test conditions ........................................................................................................................................................................................ 9

6.2 List of the recommended standards ..................................................................................................................................10

7 Organic and organic composite materials ..............................................................................................................................11

7.1 Organic materials ...............................................................................................................................................................................11

7.1.1 General...................................................................................................................................................................................11

7.1.2 Test conditions................................................................................................................................................................11

7.2 Organic composite materials ...................................................................................................................................................11

7.2.1 General...................................................................................................................................................................................11

7.2.2 Test conditions in virgin state ...........................................................................................................................11

7.2.3 Test conditions in charred state ......................................................................................................................12

7.3 List of the recommended standards ..................................................................................................................................12

8 Ceramic and associated composite materials .....................................................................................................................12

8.1 Test conditions .....................................................................................................................................................................................12

8.2 List of the recommended standards ..................................................................................................................................13

8.2.1 Ceramic .................................................................................................................................................................................13

8.2.2 Ceramic composite ......................................................................................................................................................13

Bibliography .............................................................................................................................................................................................................................14

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This document was prepared by Technical Committee ISO/TC 20, Aircraft and space vehicles,

Any feedback or questions on this document should be directed to the user’s national standards body. A

New regulations require unmanned spacecraft and launch vehicle orbital stages, called space bodies in

this document, to be designed and manufactured in such way that fragments generated during Earth

re-entry cannot cause casualties, damage to property or environmental pollution on the ground (see

Space bodies are submitted to high aero-thermodynamic fluxes, pressures and shear stresses that

lead to their disintegration into fragments that can potentially reach ground after a re-entry. These

fragments are generated by the effect of aero-thermal loads seen by components that constitute a space

body. The assessment of the fragmentation and subsequent survivability of the fragments in terms of

The methodology to determine the size of the debris is based on an idealized two-step process, called

Based on the knowledge of the orbital (ballistic) trajectory of the space body and the knowledge

of its design, the computation of temperature and stresses determine the most probable failure

locations that will generate sub components. The breakup fragments prior to re-entry are termed

The objective is then to determine if debris can survive (no completely burned), and then if the final

size and energy when touching down the Earth are in accordance with the international regulation.

The computation of the final size and energy of the debris is based on generic geometry definition,

For both fragmentation and survivability, suitable thermal response models require a range of material

Thermal tests used to determine material properties need to be well defined and shared between

There are a range of relevant spacecraft materials, from metals, organic and ceramics to composite

As a result, the material or component properties used in break­up models is an essential model input.

Objects that separate during the ascent phase and impact the ground are addressed in ISO 14620-2.

Assessment, mitigating and control of potential risks created by the re-enter of objects from the orbit

This document defines the elementary thermal tests to obtain thermal properties of materials and

composite materials used to manufacture space body to support the fragmentation and survivability

ISO and IEC maintain terminology databases for use in standardization at the following addresses:

chemical change and removal of surface material (3.1.12) due to the action of external high temperature

Note 1 to entry: Ablation can be a chemical process, addressing chemical reaction (gas-solid or gas-liquid);

Note 2 to entry: Ablation can be a physical process addressing vaporization, melting, fusion;

Note 3 to entry: Ablation can be a mechanical process addressing phenomena of erosive process (applied to solid

or liquid surface) linked to pressure effect and wall shear stress due to high-speed motion.

[SOURCE: EN 16603-31:2014, 3.2.4.2, modified — Notes 1, 2 and 3 to entry have been added.]

event that completely or partially destroys an object and generates space debris (3.1.18)

Note 1 to entry: Debris generated during earth re-entry (3.1.16) can survive and fall to the ground.

altitude when the main structural fragmentation occurs leading several components (3.1.5)

Note 1 to entry: Altitude break-up (3.1.2) can occur on a wide range of values depending on trajectories and

Note 1 to entry: The concept “ceramic” comprises products based on clay as raw material and also materials

which are typically based on oxides, nitrides, carbides, silicides, borides, carbon etc.

set of materials (3.1.12), assembled according to defined and controlled processes, which cannot be

disassembled without destroying its capability and which performs a simple function that can be

combination of materials (3.1.12) different in composition or form on a macro scale

Note 2 to entry: The constituents can normally be physically identified, and there is an interface between them.

quotient of the radiant exitance of a radiator and the radiant exitance of a Planckian radiator at the

where M is the radiant exitance of a thermal radiator and M is the radiant exitance of a Planckian

Note 1 to entry: Emissivity of any surface is a function of wavelength, direction, temperature, and surface

Note 2 to entry: Emittance is a property of a particular object. It is determined by material (3.1.12) emissivity,

surface roughness, of angle of incidence, oxidation, the sample's thermal and mechanical history, surface finish,

and measured wavelength range. Although emissivity is a major component in determining emittance, the

emissivity determined under laboratory conditions seldom agrees with actual emittance of a certain sample.

[SOURCE: ISO 80000-7:2019, item 7-30.1, modified — Notes 1 and 2 to entry have been added.]

total radiance, L , emitted by the considered surface, divided by total radiance emitted by the black

Note 1 to entry: Determined in the domain of near infrared (NIR) and middle infrared (MIR) of the infrared

spectral radiance, L , of the considered surface divided by the spectral radiance emitted by the black

Note 1 to entry: Determined in the domain of near infrared (NIR) and middle infrared (MIR) of the infrared

total hemispherical exitance, M, of the considered surface divided by the total hemispherical exitance of

Note 1 to entry: Determined in the domain of near infrared (NIR) and middle infrared (MIR) of the infrared

inorganic material (3.1.12) produced by the complete fusion of raw materials at high temperatures into

a homogeneous liquid which is then cooled to a rigid condition and temperature treated in such a way

characteristic value of the temperature range over which the glass transition takes place

Note 1 to entry: Glass transition temperature characterizes the transition from true solid to very viscous liquid.

Note 2 to entry: The assigned glass transition temperature (Tg) may vary, depending on the specific property

Note 1 to entry: For infrared radiation, the range between 780 nm and 1 mm is commonly subdivided into:

Note 3 to entry: For break-up (3.1.2) models (3.1.14), NIR and MIR are the must representative wavelength

[SOURCE: ISO 9488:1999, 3.9, modified — Notes 1, 2 and 3 to entry have been added.]

complete element of a launch vehicle that is designed to deliver a defined thrust during a dedicated

Note 1 to entry: Non-propulsive elements of a launch vehicle, such as jettisonable tanks, multiple payload

structures or dispensers, are considered to be part of a launch vehicle orbital stage while they are attached.

raw, semi-finished or finished purchased item (gaseous, liquid, solid) of given characteristics from

Note 1 to entry: At the melting point the solid and liquid phases exist in equilibrium for a single substance. The

melting point of a solid depends on pressure and is usually specified at standard pressure.

Note 2 to entry: Solids, which differ from single substances and eutectics, do not have a sharp melting point

because fusion occurs in a wide temperature range. Therefore, there is a temperature of beginning of fusion

Note 3 to entry: Amorphous solids (including many polymers) do not have a sharp melting point. When these pass

from a solid to fluid state, they do so over a wide temperature range, centred roughly about the glass transition

Note 4 to entry: The determination method of the melting point used in the break-up (3.1.2) model (3.1.14) shall

be mentioned if it is liquidus state, solidus state or even as an average of solidus and liquidus.

Note 5 to entry: By conservatism, liquidus is preferred in order to state that no solid debris can fall on ground.

Note 6 to entry: Carbon does not melt at any temperature under standard pressure; instead it sublimes around

physical or abstract representation of relevant aspects of an item or process that is put forward as a

Note 1 to entry: The term “model” can also be used to identify particular instances of the product, e.g. flight

Note 1 to entry: Sometimes used in a more restricted sense to describe chemical changes resulting from heat

return of a spacecraft (3.1.19) or other space object into the Earth’s atmosphere

Note 1 to entry: Several alternative definitions are available for the boundary between the Earth’s atmosphere

specific heat capacity determined with DSC where all heat contributions (endothermic and exothermic)

due to chemical transformation of the material (3.1.12) are not taken into account to measure the

non­functional fragments of, or residue from, a space segment element, or launch segment element, in

[SOURCE: ISO 10795:2019, 3.219, modified — The deprecated term has been removed.]

[SOURCE: ISO 10795:2019, 3.224, modified — The abbreviated term and Note 1 to entry have been

Unmanned spacecraft and launch vehicle orbital stages are made with different components based on

metals, polymers, ceramics and composite materials made with polymers, metals and ceramics.

The test matrix (type of test and environmental experimental conditions) shall be determined with

respect to the complexity of the break-up model and the re-entry mode that provides the temperature

Depending on the type of re-entry (controlled versus natural) of the spacecraft, one can define two

temperature domains associated with high dynamic pressure and aerothermal loads or high energy,

For controlled re-entry, the entry speed is maximized when the flight path angle allows the temperature

For uncontrolled re-entry, the trajectory speed and low flight path angle are naturally decaying slowly.

In these conditions, the theoretical heat fluxes and dynamic pressure can lead to lower break-up

altitude of the main parts and consequently the temperature of the parts can be lower than 1 500 K.

Even if the reality is more complex, for practical reasons, two domains of temperature can be defined

to specify the temperature range of the test matrix. This temperature boundary of 1 500 K is not fixed

but should be adapted to take into account important evolutions of the material and its thermo-physical

Elementary thermal tests can characterize basic properties, such as thermal conductivity, specific heat

capacity and chemical effects inclusive of melt and pyrolysis. These bulk properties are independent of

In order to produce a reasonable prediction of the survivability of an object during the re-entry, it is

necessary to take into account mass and energy transfer occurring between the object surface and the

environmental gas. Surface properties and characteristics, such as emissivity, catalicity of the object,

The available data is often restricted to a temperature domain, which is generally well below the real or

Technological tests (complementary to elementary tests) are consequently required to extend the

domain temperature in a more relevant surface state so that surface mass and energy transfer are

The first type is radiative (generally in the infrared wavelength domain), where a furnace may be used

to expose one face of the material sample to highly calibrated pure radiative heat flux in air at ambient

pressure or in vacuum. This allows capturing of the material emissivity, the roughness and some

chemical effects that contribute to the surface mass and energy transfer. Convective flow effects on the

The second method to generate high temperature and pseudo flight representative aerothermal

loads consists in the use of plasma wind tunnel facilities. These facilities can capture effects such as

the material chemical catalicity to the recombination of air molecules at the surface, and the thermo-

a) Tested samples shall be representative to the materials used in the real part even if the thickness

b) Elementary thermal tests shall be performed on test samples of monolithic material to solve the

energy balance conservation equation (including Fourier’s law in case of multidimensional object)

by knowing the density, reversible specific heat capacity, thermal conductivity, glass transition

temperature, melting point, and enthalpy of fusion . Total hemispherical emissivity tests are also

NOTE Thermal conductivity is often determined indirectly with diffusivity measurement. Thermal

c) Due to the uncertainties of the measurements of thermo-physical material properties, the number

of test samples to identify each thermal property measured in laboratories shall be selected with

In case of material scattering, a minimum of 5 measurements for each characteristic determined for

each test condition are recommended if the statistic distribution can be fitted by a Gaussian law.

Degradations are based on different mechanisms: fusion, pyrolysis and chemical ablation. Mechanical

a) For metal and metal composite materials, oxidation, melting and chemical ablation shall be

b) For ceramic and ceramic composite materials, oxidation, melting and chemical ablation shall be

NOTE 3 Carbon/carbon composite materials are considered as ceramic composite materials.

c) For organic and organic composite materials, melting, pyrolysis and chemical ablation driven by