ISO/DTR 6832

Space systems — Development technology of a thermal vacuum chamber

Systèmes spatiaux — Technologie de développement d'une chambre thermique sous vide

General Information

• Status: Not Published
• 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: 5020 - FDIS ballot initiated: 2 months. Proof sent to secretariat
• Start Date: 28-Jun-2023
• Completion Date: 28-Jun-2023

Standards Content (Sample)

FINAL
TECHNICAL ISO/DTR
DRAFT
REPORT 6832
ISO/TC 20/SC 14
Space systems — Development
Secretariat: ANSI
technology of a thermal vacuum
Voting begins on:
2023-06-28 chamber
Voting terminates on:
Systèmes spatiaux — Technologie de développement d'une chambre
2023-08-23
thermique sous vide
RECIPIENTS OF THIS DRAFT ARE INVITED TO
SUBMIT, WITH THEIR COMMENTS, NOTIFICATION
OF ANY RELEVANT PATENT RIGHTS OF WHICH
THEY ARE AWARE AND TO PROVIDE SUPPOR TING
DOCUMENTATION.
IN ADDITION TO THEIR EVALUATION AS
Reference number
BEING ACCEPTABLE FOR INDUSTRIAL, TECHNO-
ISO/DTR 6832:2023(E)
LOGICAL, COMMERCIAL AND USER PURPOSES,
DRAFT INTERNATIONAL STANDARDS MAY ON
OCCASION HAVE TO BE CONSIDERED IN THE
LIGHT OF THEIR POTENTIAL TO BECOME STAN-
DARDS TO WHICH REFERENCE MAY BE MADE IN
NATIONAL REGULATIONS. © ISO 2023
---------------------- Page: 1 ----------------------
ISO/DTR 6832:2023(E)
FINAL
TECHNICAL ISO/DTR
DRAFT
REPORT 6832
ISO/TC 20/SC 14
Space systems — Development
Secretariat: ANSI
technology of a thermal vacuum
Voting begins on:
chamber
Voting terminates on:
Systèmes spatiaux — Technologie de développement d'une chambre
thermique sous vide
COPYRIGHT PROTECTED DOCUMENT
© ISO 2023

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.
RECIPIENTS OF THIS DRAFT ARE INVITED TO
ISO copyright office
SUBMIT, WITH THEIR COMMENTS, NOTIFICATION
OF ANY RELEVANT PATENT RIGHTS OF WHICH
CP 401 • Ch. de Blandonnet 8
THEY ARE AWARE AND TO PROVIDE SUPPOR TING
CH-1214 Vernier, Geneva
DOCUMENTATION.
Phone: [phone]
IN ADDITION TO THEIR EVALUATION AS
Reference number
Email: [e-mail]
BEING ACCEPTABLE FOR INDUSTRIAL, TECHNO­
ISO/DTR 6832:2023(E)
Website: www.iso.org
LOGICAL, COMMERCIAL AND USER PURPOSES,
DRAFT INTERNATIONAL STANDARDS MAY ON
Published in Switzerland
OCCASION HAVE TO BE CONSIDERED IN THE
LIGHT OF THEIR POTENTIAL TO BECOME STAN­
DARDS TO WHICH REFERENCE MAY BE MADE IN
© ISO 2023 – All rights reserved
NATIONAL REGULATIONS. © ISO 2023
---------------------- Page: 2 ----------------------
ISO/DTR 6832:2023(E)
Contents Page

Foreword ..........................................................................................................................................................................................................................................v

Introduction .............................................................................................................................................................................................................................. vi

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

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

3 Terms and definitions .................................................................................................................................................................................... 1

4 Symbols and abbreviated terms..........................................................................................................................................................2

5 Vacuum and thermal environment simulation ................................................................................................................... 2

5.1 General ........................................................................................................................................................................................................... 2

5.2 Vacuum environment simulation technology ............................................................................................................. 3

5.3 Cold black environment simulation technology ....................................................................................................... 3

5.4 Space heat flux simulation technology .............................................................................................................................. 3

5.4.1 General ........................................................................................................................................................................................ 3

5.4.2 Incident heat flux simulation technology ..................................................................................................... 3

5.4.3 Absorbed heat flux simulation technology ................................................................................................. 4

6 Design of TVC ........................................................................................................................................................................................................... 4

6.1 Configuration of TVC ......................................................................................................................................................................... 4

6.2 General design ........................................................................................................................................................................................ 5

7 Vacuum vessel ......................................................................................................................................................................................................... 6

7.1 Composition and function ............................................................................................................................................................ 6

7.2 Vessel design ............................................................................................................................................................................................ 6

7.2.1 Structure shape ................................................................................................................................................................... 6

7.2.2 Material....................................................................................................................................................................................... 8

7.2.3 Structure design ................................................................................................................................................................. 9

7.2.4 Design calculation ..........................................................................................................................................................12

7.2.5 Manufacturing ...................................................................................................................................................................12

8 Shroud ..........................................................................................................................................................................................................................12

8.1 Composition and function ......................................................................................................................................................... 12

8.2 Shroud design ....................................................................................................................................................................................... 13

8.2.1 Material of shroud .......................................................................................................................................................... 13

8.2.2 Structure of shroud .......................................................................................................................................................13

8.2.3 Shroud area division and thermal design ................................................................................................. 14

8.2.4 Decontamination panel design ........................................................................................................................... 14

8.2.5 Temperature measurement ................................................................................................................................... 15

8.2.6 Inner surface painting ................................................................................................................................................15

8.2.7 Leak testing.......................................................................................................................................................................... 15

9 Nitrogen system .................................................................................................................................................................................................15

9.1 Composition and function .........................................................................................................................................................15

9.2 Design of LN subsystem ............................................................................................................................................................15

9.2.1 Technical scheme ............................................................................................................................................................15

9.2.2 Equipment configuration ......................................................................................................................................... 18

9.2.3 Piping design ....................................................................................................................................................................... 18

9.3 Design of GN subsystem ........................................................................................................................................... ................. 19

9.3.1 Technical scheme ............................................................................................................................................................ 19

9.3.2 Equipment configuration ......................................................................................................................................... 20

10 Vacuum system ...................................................................................................................................................................................................21

10.1 Composition and function ......................................................................................................................................................... 21

10.2 Design of vacuum system........................................................................................................................................................... 21

10.2.1 General ..................................................................................................................................................................................... 21

10.2.2 Scheme of the vacuum pumping process ................................................................................................... 21

10.2.3 System design calculations .................................................................................................................................... 22

iii
© ISO 2023 – All rights reserved
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ISO/DTR 6832:2023(E)

10.2.4 Equipment configuration ......................................................................................................................................... 23

11 Heat flux simulation system .................................................................................................................................................................25

11.1 Solar simulator .................................................................................................................................................................................... 25

11.1.1 Composition and function ....................................................................................................................................... 25

11.1.2 Solar simulator design ................................................................................................................................................ 26

11.2 Infrared heat flux simulator .................................................................................................................................................... 31

11.2.1 Composition and function ....................................................................................................................................... 31

11.2.2 Infrared lamp array ...................................................................................................................................................... 31

11.2.3 Infrared cage ........................................................................................................................................... ............................33

11.2.4 Thermal controlled panel ........................................................................................................................................34

12 Specimen support mechanism ...........................................................................................................................................................34

12.1 General ........................................................................................................................................................................................................34

12.2 Motion simulator ............................................................................................................................................................................... 35

12.2.1 Composition and function ....................................................................................................................................... 35

12.2.2 Motion simulator design ........................................................................................................................................... 35

12.3 Horizontal adjustment mechanism ................................................................................................................................... 37

12.3.1 Composition and function ....................................................................................................................................... 37

12.3.2 Design of horizontal adjustment mechanism ........................................................................................ 37

12.4 Test specimen support ......... .........................................................................................................................................................38

12.4.1 Composition and function .......................................................................................................................................38

12.4.2 Design of test specimen support .......................................................................................................................38

13 Measurement and control system ..................................................................................................................................................39

13.1 Composition and function .........................................................................................................................................................39

13.2 Measurement and control system design .................................................................................................................... 39

13.2.1 General .....................................................................................................................................................................................39

13.2.2 Structure of measurement and control system ...................................................................................39

13.2.3 Measurement and control system hardware and software platform .............................40

13.2.4 Function implementation of measurement and control system ........................................... 41

14 Logistic support system ............................................................................................................................................................................42

Bibliography .............................................................................................................................................................................................................................43

© ISO 2023 – All rights reserved
---------------------- Page: 4 ----------------------
ISO/DTR 6832:2023(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 non­governmental, 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.

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).

ISO draws attention to the possibility that the implementation of this document may involve the use

of (a) patent(s). ISO takes no position concerning the evidence, validity or applicability of any claimed

patent rights in respect thereof. As of the date of publication of this document, ISO had not received

notice of (a) patent(s) which may be required to implement this document. However, implementers are

cautioned that this may not represent the latest information, which may be obtained from the patent

database available at www.iso.org/patents. ISO shall not be held responsible for identifying any or all

such patent rights.

Any trade name used in this document is information given for the convenience of users and does not

constitute an endorsement.

For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and

expressions related to conformity assessment, as well as information about ISO's adherence to

the World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT), see

www.iso.org/iso/foreword.html.

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

Subcommittee SC 14, Space systems and operations.

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.
© ISO 2023 – All rights reserved
---------------------- Page: 5 ----------------------
ISO/DTR 6832:2023(E)
Introduction

Since the first artificial satellite was launched into space successfully in 1957, space activities have been

developed over the decades. The large amount of experience collected during that period demonstrates

that a significant number of failures or defects appearing during spacecraft in-orbit operation were

induced by space environment factors. These factors include space vacuum, cold black background,

solar radiation, and also albedo and eigenradiation of the Earth. Therefore, thermal balance tests and

thermal vacuum tests for spacecraft are performed in a simulated environment generated by ground

simulation facilities in order to evaluate spacecraft performance, to verify thermal analysis models,

and to discover early failures and defects in the spacecraft design and manufacturing process.

Countries engaged in spacecraft development have established several thermal test facilities, known as

thermal vacuum chambers. They also have standardized requirements for thermal vacuum tests and

thermal balance tests. These efforts greatly improved spacecraft reliability and played an important

role in space activities.

A thermal vacuum chamber is designed to simulate vacuum, cold black and heat flux environment that

a spacecraft experiences during its mission in space. It is composed of vacuum vessel, shroud, nitrogen

system, vacuum system, heat flux simulation system, specimen support mechanism, measurement and

control system, etc. Based on the state-of-the-art simulation technology, the relevant test standards and

experiences accumulated from facilities development, this document provides development technology

of a thermal vacuum chamber.
© ISO 2023 – All rights reserved
---------------------- Page: 6 ----------------------
TECHNICAL REPORT ISO/DTR 6832:2023(E)
Space systems — Development technology of a thermal
vacuum chamber
1 Scope

This document describes the technology for simulating space environments such as vacuum, cold black,

and heat flux, as well as the compositions and functions of a thermal vacuum chamber (TVC). This kind

of facility defined in this document is suitable for thermal vacuum tests (TVT) and thermal balance

tests (TBT) on spacecraft-system level as well as on large-spacecraft-component level.

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
thermal vacuum chamber
TVC
space environment simulator

facility to simulate the space vacuum, cold black, and heat flux environment on the ground

Note 1 to entry: It is used for thermal vacuum tests (TVT) (3.4) and thermal balance tests (TBT) (3.5) of spacecraft.

3.2
shroud

subsystem of a thermal vacuum chamber (TVC) (3.1) to simulate the cold black environment (3.3) in space

Note 1 to entry: It is cooled by liquid nitrogen or gaseous nitrogen to simulate the cold black environment in

space. It is also called heat sink.
3.3
cold black environment

space environment without considering the solar and Earth radiation and the Earth's atmospheric

albedo

Note 1 to entry: The radiated energy from spacecraft under cold black environment will be completely absorbed.

3.4
thermal vacuum test
TVT

test which is conducted to demonstrate the capability of the test item and to operate according to

requirements in vacuum at predefined temperature conditions

Note 1 to entry: A spacecraft is validated by a thermal balance test (TBT) (3.5) and a thermal vacuum test (TVT)

in a similar environment provided by a thermal vacuum chamber (TVC) (3.1) prior to launch.

© ISO 2023 – All rights reserved
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ISO/DTR 6832:2023(E)
3.5
thermal balance test
TBT

test which is conducted to verify the adequacy of the thermal model and the adequacy of the thermal

design

Note 1 to entry: A spacecraft is validated by a thermal balance test (TBT) and a thermal vacuum test (TVT) (3.4)

in a similar environment provided by a thermal vacuum chamber (TVC) (3.1) prior to launch.

3.6
simulation chamber
main body of a thermal vacuum chamber (TVC) (3.1)

Note 1 to entry: It includes vacuum vessel and shroud (3.2) and provides test space for spacecrafts.

4 Symbols and abbreviated terms
B/S browser/server
C/S client/server
DCS distributed control system
FCS field bus control system
GN gas nitrogen
HMI human­machine interface
LAN local area network
LN liquid nitrogen
NPSH net positive suction head
PLC programmable logic controller
SCADA supervisory control and data acquisition
SS stainless steel
TVC thermal vacuum chamber
TBT thermal balance test
TCU thermal conditioning unit
TVT thermal vacuum test
5 Vacuum and thermal environment simulation
5.1 General

Spacecrafts in-orbit are exposed to high vacuum, cold black and heat flux radiation environment.

Therefore, a spacecraft is validated by TBT and TVT in a similar environment provided by a TVC prior

to launch. This allows to evaluate the thermal control system's performance, to verify the thermal

analysis model, to discover early failures and defects in spacecraft design and manufacturing process,

and to check the performance of spacecraft in extreme high and low temperatures. With decades of

© ISO 2023 – All rights reserved
---------------------- Page: 8 ----------------------
ISO/DTR 6832:2023(E)

technical development and the establishment of testing standards, the simulation methodology for the

three environmental factors (vacuum, cold black and heat flux) tends to be mature.

5.2 Vacuum environment simulation technology

The pressure in space varies with the orbital altitude of the spacecraft. The higher the orbital altitude

is, the lower the pressure would be. The pressure at the Earth's sea level is about 1,013×10 Pa, and the

­2 ­12

pressure in the flight orbit of Earth spacecrafts is between 10 Pa and 10 Pa. According to the heat

exchange theory, under the condition that the pressure is lower than 10 Pa, heat exchange between

spacecrafts and space environment is mainly radiation, and conduction and convective heat transfer

is negligible. According to the purpose and standards of TVT and TBT of spacecraft, the vacuum

environment simulation is satisfied when the test specimen is under test condition with not higher than

1,33×10 Pa. According to the development of vacuum acquisition technology, Roots pump-dry pump

unit, molecular pump and cryopump are generally combined for obtaining an ultimate pressure about

­5 ­2

10 Pa under non-load condition, so as to ensure that the pressure is not higher than 1,33×10 Pa with

load and meet the test for spacecrafts.
5.3 Cold black environment simulation technology

Without considering the solar radiation and earth (or other planet) albedo and eigenradiation, deep

space is similar to an infinite dissipation black body. Under such conditions a passive body experiences

a balance temperature between −270,15 °C (3 K) and −269,15 °C (4 K), and the black body energy

­6 2

density is about 5×10 W/m . This concept, known as cold black environment, implies that the heat

emitted by a spacecraft will be absorbed completely. The device on the ground which simulates this

environment is called shroud. However, to generate the exact space environment on the ground is

economically unviable and proved to be unnecessary. Based on the error analysis, generating an

environment of below 100 K, shroud absorptivity of about 0,95, and shroud emissivity of no less than

0,9 can reduce the temperature error on the spacecraft to less than 1 % under vacuum environment.

Therefore, the state-of-the-art simulation requirement for cold black environment requires a balance of

performance, cost and schedule that can be achieved in the design and production of thermal systems.

Typically shroud consists of SS or aluminium. Its surfaces facing towards the test volume are coated

with black paint to obtain high absorptivity (α) and high emissivity (ε). The volume inside of the shroud

is part of a cooling circuit with fluids that are capable of cooling down the shroud to a temperature of

approximately −173,15 °C (100 K). Nitrogen with a boiling point at 77 K is widely used for that purpose

since it is relatively cheap compared to hydrogen, oxygen or helium.
5.4 Space heat flux simulation technology
5.4.1 General

The external heat flux experienced by spacecrafts in Earth orbit comes from solar radiation, albedo and

eigenradiation of the earth. The space heat flux is simulated in two different ways, the incident heat flux

simulation and the absorbed heat flux simulation.
5.4.2 Incident heat flux simulation technology

The incident heat flux method is used to simulate the effect of solar radiation only. For the incident heat

flux method, the heat flux is generated by a solar simulator.

A predefined volume of the thermal vacuum chamber is exposed to solar type energetic illumination

which complies in each respect with the basic parameters of the sun: irradiance, spectrum, divergence,

illumination stability, and spatial uniformity. This is typically achieved by collect light from xenon

lamps through an arrangement of lenses and mirrors. The light beam is focused and superimposed to

the predefined volume. Typically, a solar simulator provides the range of irradiance from 0,5 to 1,3 solar

constant and collimation angle of no more than ±2°. A solar simulator provides an accurate simulation

of the actual solar spectrum. A solar simulator is restricted in application due to high­cost, complicated

© ISO 2023 – All rights reserved
---------------------- Page: 9 ----------------------
...

ISO/DTR 6832
ISO/TC 20/SC 14/WG 2
Secretariat: ANSI/AIAA
Date: 2023-06-14
Space systems – — Development technology of a thermal vacuum
chamber
DTR
Warning for WDs and CDs

This document is not an ISO International Standard. It is distributed for review and comment. It is

subject to change without notice and may not be referred to as an International Standard.

Recipients of this draft are invited to submit, with their comments, notification of any relevant patent

rights of which they are aware and to provide supporting documentation.
---------------------- Page: 1 ----------------------
© ISO/IEC 2021

Systèmes spatiaux — Technologie de développement d'une chambre thermique sous vide

FDIS stage
---------------------- Page: 2 ----------------------
ISO/DTR 6832:(E)
© ISO 2023

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.

International Organization for Standardization
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: + 41 22 749 01 11
Fax: [phone]
EmailE-mail: [e-mail]
Website: www.iso.org
Published in Switzerland
© ISO 2023 – All rights reserved iii
---------------------- Page: 3 ----------------------
ISO/DTR 6832:(E)
Contents

Foreword ............................................................................................................................................................................................ vi

Introduction ......................................................................................................................................................................................vi i

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

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

3 Terms and definitions ...................................................................................................................................................... 1

4 Symbols and abbreviated terms .................................................................................................................................. 2

5 Vacuum and thermal environment simulation ...................................................................................................... 2

5.1 General ................................................................................................................................................................................... 2

5.2 Vacuum environment simulation technology ........................................................................................................ 3

5.3 Cold black environment simulation technology ................................................................................................... 3

5.4 Space heat flux simulation technology ...................................................................................................................... 3

5.4.1 General ............................................................................................................................................................................... 3

5.4.2 Incident heat flux simulation technology ............................................................................................................ 3

5.4.3 Absorbed heat flux simulation technology ......................................................................................................... 4

6 Design of TVC ....................................................................................................................................................................... 4

6.1 Configuration of TVC ........................................................................................................................................................ 4

6.2 General design ..................................................................................................................................................................... 5

7 Vacuum vessel ..................................................................................................................................................................... 6

7.1 Composition and function .............................................................................................................................................. 6

7.2 Vessel design ........................................................................................................................................................................ 6

7.2.1 Structure shape .............................................................................................................................................................. 6

7.2.2 Material ............................................................................................................................................................................. 9

7.2.3 Structure design ............................................................................................................................................................. 9

7.2.4 Design calculation ...................................................................................................................................................... 13

7.2.5 Manufacturing ............................................................................................................................................................. 13

8 Shroud ................................................................................................................................................................................. 14

8.1 Composition and function ........................................................................................................................................... 14

8.2 Shroud design ................................................................................................................................................................... 14

8.2.1 Material of shroud ...................................................................................................................................................... 14

8.2.2 Structure of shroud ................................................................................................................................................... 15

8.2.3 Shroud area division and thermal design ........................................................................................................ 15

8.2.4 Decontamination panel design ............................................................................................................................. 16

8.2.5 Temperature measurement ................................................................................................................................... 16

8.2.6 Inner surface painting .............................................................................................................................................. 16

8.2.7 Leak testing ................................................................................................................................................................... 16

9 Nitrogen system ............................................................................................................................................................... 16

9.1 Composition and function ........................................................................................................................................... 16

9.2 Design of LN subsystem ............................................................................................................................................. 16

iv © ISO 2023 – All rights reserved
---------------------- Page: 4 ----------------------
ISO/DTR 6832:(E)

9.2.1 Technical scheme ....................................................................................................................................................... 16

9.2.2 Equipment configuration ........................................................................................................................................ 19

9.2.3 Piping design ................................................................................................................................................................ 19

9.3 Design of GN subsystem ............................................................................................................................................. 20

9.3.1 Technical scheme ....................................................................................................................................................... 20

9.3.2 Equipment configuration ........................................................................................................................................ 21

10 Vacuum system ................................................................................................................................................................ 22

11 Heat flux simulation system ....................................................................................................................................... 27

11.1 Solar simulator ................................................................................................................................................................. 27

11.1.1 Composition and function ...................................................................................................................................... 27

11.1.2 Solar simulator design ............................................................................................................................................. 28

11.2 Infrared heat flux simulator ....................................................................................................................................... 34

11.2.1 Composition and function ...................................................................................................................................... 34

11.2.2 Infrared lamp array ................................................................................................................................................... 34

11.2.3 Infrared cage ................................................................................................................................................................ 37

11.2.4 Thermal controlled panel ....................................................................................................................................... 38

12 Specimen support mechanism .................................................................................................................................. 38

12.1 General ................................................................................................................................................................................ 38

12.2 Motion simulator ............................................................................................................................................................. 39

12.2.1 Composition and function ...................................................................................................................................... 39

12.2.2 Motion simulator design ......................................................................................................................................... 39

12.3 Horizontal adjustment mechanism ......................................................................................................................... 41

12.3.1 Composition and function ...................................................................................................................................... 41

12.3.2 Design of horizontal adjustment mechanism ................................................................................................. 41

12.4 Test specimen support ................................................................................................................................................. 42

12.4.1 Composition and function ...................................................................................................................................... 42

12.4.2 Design of test specimen support .......................................................................................................................... 43

13 Measurement and control system ............................................................................................................................ 44

13.1 Composition and function ........................................................................................................................................... 44

13.2 Measurement and control system design ............................................................................................................. 44

13.2.1 General ............................................................................................................................................................................ 44

13.2.2 Structure of measurement and control system ............................................................................................. 44

13.2.3 Measurement and control system hardware and software platform................................................... 45

13.2.4 Function implementation of measurement and control system ............................................................ 46

14 Logistic support system ............................................................................................................................................... 47

Bibliography .................................................................................................................................................................................... 48

© ISO 2023 – All rights reserved v
---------------------- Page: 5 ----------------------
ISO/DTR 6832:(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.

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 documentsdocument 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).

Attention is drawnISO draws attention to the possibility that some of the elementsimplementation of this

document may beinvolve the subjectuse of (a) patent(s). ISO takes no position concerning the evidence,

validity or applicability of any claimed patent rights in respect thereof. As of the date of publication of

this document, ISO had not received notice of (a) patent(s) which may be required to implement this

document. However, implementers are cautioned that this may not represent the latest information,

which may be obtained from the patent database available at www.iso.org/patents.. ISO shall not be held

responsible for identifying any or all such patent rights. Details of any patent rights identified during the

development of the document will be in the Introduction and/or on the ISO list of patent declarations

received (see ).

Any trade name used in this document is information given for the convenience of users and does not

constitute an endorsement.

For an explanation onof the voluntary nature of standards, the meaning of ISO specific terms and

expressions related to conformity assessment, as well as information about ISO's adherence to the World

Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT)), see

www.iso.org/iso/foreword.htmlthe following URL: .

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

Subcommittee SC 14, Space systems and operations.

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.
vi © ISO 2023 – All rights reserved
---------------------- Page: 6 ----------------------
ISO/DTR 6832:(E)
Introduction

Since the first artificial satellite was launched into space successfully in 1957, space activities have been

developed over the decades. The large amount of experience collected during that time period

demonstrates that a significant number of failures or defects appearing during spacecraft in-orbit

operation were induced by space environment factors. These factors include space vacuum, cold black

background, solar radiation, and also albedo and eigenradiation of the Earth. Therefore, thermal balance

testtests and thermal vacuum testtests for spacecraft are performed in a simulated environment

generated by ground simulation facilities in order to evaluate spacecraft performance, to verify thermal

analysis models, and to discover early failures and defects in the spacecraft design and manufacturing

process.

Countries engaged in spacecraft development have established several thermal test facilities, known as

thermal vacuum chamber or space environment simulator.chambers. They also have standardized

requirements for thermal vacuum testtests and thermal balance testtests. These efforts greatly improved

spacecraft reliability and played an important role in space activities.

A thermal vacuum chamber is designed to simulate vacuum, cold black and heat flux environment that a

spacecraft experiences during its mission in space. It is composed of vacuum vessel, shroud, nitrogen

system, vacuum system, heat flux simulation system, specimen support mechanism, measurement &and

control system, etc. Based on the state-of-the-art simulation technology, the relevant test standards and

experiences accumulated from facilities development, this technical reportdocument provides

development technology of a thermal vacuum chamber.
© ISO 2023 – All rights reserved vii
---------------------- Page: 7 ----------------------
Space systems - — Development technology of a thermal vacuum
chamber
1 Scope

This reportdocument describes the technology for simulating space environments such as vacuum, cold

black, and heat flux, as well as the compositions and functions of a thermal vacuum chamber (TVC). This

kind of facility defined in this technical reportdocument is suitable for thermal vacuum testtests (TVT)

and thermal balance testtests (TBT) on spacecraft-system -level as well as on large-spacecraft-

component level.
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
thermal vacuum chamber
TVC
space environment simulator

facility to simulate the space vacuum, cold black, and heat flux environment on the ground

Note 1 to entry: It is used for thermal vacuum testtests (TVT) (3.4) and thermal balance testtests (TBT) (3.5) of

spacecraft.
3.2
shroud

a subsystem of a thermal vacuum chamber (TVC () (3.1) to simulate the space cold black environment (3.3)

in space

Note 1 to entry: It is cooled by liquid nitrogen or gaseous nitrogen to simulate the cold black environment in space.

It is also called heat sink.
3.3
cold black environment

space environment without considering the solar and Earth radiation and the Earth's atmospheric albedo

Note 1 to entry: The radiated energy from spacecraft under cold black environment will be completely absorbed.

3.4
thermal vacuum test
TVT

test which is conducted to demonstrate the capability of the test item and to operate according to

requirements in vacuum at predefined temperature conditions

Note 1 to entry: a A spacecraft is validated by a thermal balance test (TBT) (3.5) and a thermal vacuum test (TVT)

in a similar environment provided by a thermal vacuum chamber (TVC () (3.1) prior to launch.

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ISO/DTR 6832:(E)
3.5
thermal balance test
TBT

test which is conducted to verify the adequacy of the thermal model and the adequacy of the thermal

design

Note 1 to entry: a A spacecraft is validated by a thermal balance test (TBT) and a thermal vacuum test (TVT) (3.4 ()

) in a similar environment provided by a thermal vacuum chamber (TVC () (3.1) prior to launch.

3.6
simulation chamber
main body of a thermal vacuum chamber (TVC () (3.1)

Note 1 to entry: It includes vacuum vessel and shroud (3.2(),) and provides test space for spacecrafts.

4 Symbols and abbreviated terms
B/S browser/server
C/S client / /server
DCS distributed control system
FCS field bus control system
GN gas nitrogen
HMI human-machine interface
LAN local area network
LN liquid nitrogen
NPSH net positive suction head
PLC programmable logic controller
SCADA supervisory control and data acquisition
SS stainless steel
TVC thermal vacuum chamber
TBT thermal balance test
TCU thermal conditioning unit
TVT thermal vacuum test
UPS uninterruptible power supply
85 Vacuum and thermal environment simulation
8.15.1 General

Spacecrafts in-orbit are exposed to high vacuum, cold black and heat flux radiation environment.

Therefore, a spacecraft is validated by TBT and TVT in a similar environment provided by a TVC prior to

launch. This allows to evaluate the thermal control system's performance, to verify the thermal analysis

model, to discover early failures and defects in spacecraft design and manufacturing process, and to check

the performance of spacecraft in extreme high and low temperatures. With decades of technical

development and the establishment of testing standards, the simulation methodology for the three

environmental factors (vacuum, cold -black and heat flux) tends to be mature.
2 © ISO 2023 – All rights reserved
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ISO/DTR 6832:(E)
8.25.2 Vacuum environment simulation technology

The pressure in space varies with the orbital altitude of the spacecraft. The higher the orbital altitude is,

the lower the pressure would be. The pressure at the Earth's sea level is about 1,013×10 Pa, and the

-2 -12

pressure in the flight orbit of Earth spacecrafts is between 10 Pa and 10 Pa. According to the heat

exchange theory, under the condition that the pressure is lower than 10 Pa, heat exchange between

spacecrafts and space environment is mainly radiation, and conduction and convective heat transfer is

negligible. According to the purpose and standards of TVT &and TBT of spacecraft, the vacuum

environment simulation is satisfied when the test specimen is under test condition with not higher than

1,33×10 Pa. According to the development of vacuum acquisition technology, Roots pump-dry pump

unit, molecular pump and cryopump are generally combined for obtaining an ultimate pressure about

-5 -2

Pa under non-load condition, so as to ensure that the pressure is not higher than1than 1,33×10 Pa

with load and meet the test for spacecrafts.
8.35.3 Cold black environment simulation technology

Without considering the solar radiation and earth (or other planet) albedo and eigenradiation, deep space

is similar to an infinite dissipation black body. Under such conditions a passive body experiences a

balance temperature between −270,15 ℃ °C (3 K) and −269,15 ℃ °C (4 K)，), and the black body energy

-6 2

density is about 5×10 W/m .. This concept, known as cold -black environment, implies that the heat

emitted by a spacecraft will be absorbed completely. The device on the ground which simulates this

environment is called shroud. However, to generate the exact space environment on the ground is

economically unviable and proved to be unnecessary. Based on the error analysis, generating an

environment of below 100 K, shroud absorptivity of about 0,95, and shroud emissivity of no less than 0,9

can reduce the temperature error on the spacecraft to less than 1 % under vacuum environment.

Therefore, the state-of-the-art simulation requirement for cold -black environment requires a balance of

performance, cost and schedule that can be achieved in the design and production of thermal systems.

Typically shroud consists of stainless steel (SS) or aluminumaluminium. Its surfaces facing towards the test

volume are coated with black paint to obtain high absorptivity (α) and high emissivity (ε). The volume

inside of the shroud is part of a cooling circuit with fluids that are capable of cooling down the shroud to

a temperature of approximately -−173,15 °C (100 K). Nitrogen with a boiling point at 77 K is widely used

for that purpose since it is relatively cheap compared to hydrogen, oxygen or helium.

8.45.4 Space heat flux simulation technology
8.4.15.4.1 General

The external heat flux experienced by spacecrafts in Earth orbit comes from solar radiation, albedo and

eigenradiation of the earth. The space heat flux is simulated in two different ways, the incident heat flux

simulation and the absorbed heat flux simulation.
8.4.25.4.2 Incident heat flux simulation technology

The incident heat flux method is used to simulate the effect of solar radiation only. For the incident heat

flux method, the heat flux is generated by a solar simulator.

A predefined volume of the space environment simulatorthermal vacuum chamber is exposed to solar

type energetic illumination which complies in each respect with the basic parameters of the sun:

irradiance, spectrum, divergence, illumination stability, and spatial uniformity. This is typically achieved

by collect light from xenon lamps through an arrangement of lenses and mirrors. The light beam is

focused and superimposed to the predefined volume. Typically, a solar simulator provides the range of

irradiance from 0.,5 to 1.,3 solar constant and collimation angle of no more than ±2°. A solar simulator

provides an accurate simulation of the actual solar spectrum. A solar simulator is restricted in application

due to high-cost, complicated system and fixed illumination surface. In addition, when using a solar

simulator, the satellite can be installed on the motion simulator which guides the spacecraft with respect

to artificial solar beam.
© ISO 2023 – All rights reserved 3
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ISO/DTR 6832:(E)
8.4.35.4.3 Absorbed heat flux simulation technology

For the absorbed heat flux simulation technology, the heat flux is generated by heat sources within the

test volume. State-of-the-art, there are three ways to generate absorbed heat flux. The first way is using

infrared heat flux simulator, such as infrared lamps, infrared cage, or thermal controlled panel, to

generate infrared radiation to simulate the absorbed heat flux. The second way is using resistive film

heater attached to the specimen surface with the absorbed heat flux controlled by electrical power. The

third way is using a temperature-adjustable shroud to simulate the absorbed heat flux. It requires a set

of GN thermal conditioning unit (TCU).

PreviousThe first two ways are widely used due to the characteristics of low-cost, flexible combination

and simple system configuration. However, the equipment used for these two ways will partially block

the radiation of the shroud to the specimen during the test, which brings difficulties to the realization of

low-temperature conditions for the specimen. In addition, due to poor versatility, infrared heat flux

simulators and resistive film heaters have tomust be designed and manufactured according to the

structural dimensions and heat flux requirements of spacecrafts. When the third way is adopted, there is

no need to develop extra heat flux simulator for thermal test, which saves preparation time and cost.

However, it has low simulation accuracy and slow heat reflection.
96 Design of TVC
9.16.1 Configuration of TVC

A thermal vacuum chamber is designed to simulate vacuum, cold black and heat flux environment that a

spacecraft experiences during its mission in space. It is composed of vacuum vessel, shroud, nitrogen

system, vacuum system, heat flux simulation system, specimen support mechanism, measurement &and

control system, etc. The heat flux simulation system maycan consist of any combination of the different

...