ISO 9621:2024

Space systems — Methods to decide thermal vacuum test cycles of recurring production according to precipitation efficiency and reliability

This document provides technical methods to calculate the precipitation efficiency and liability of a flight model by measuring the screening effectiveness of thermal cycles. This document is applicable to the recurring production unit and other hardware assembly levels, as either an option to reduce or a method to tailor the baseline number of cycles for thermal vacuum and thermal cycle acceptance tests.

Systèmes spatiaux — Méthodes pour déterminer les cycles d'essais sous vide thermique de la production récurrente en fonction de l'efficacité et de la fiabilité des précipitations

General Information

• Status: Published
• Publication Date: 12-May-2024
• 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: 6060 - International Standard published
• Start Date: 13-May-2024
• Due Date: 08-Nov-2024
• Completion Date: 13-May-2024

Standards Content (Sample)

International
Standard
ISO 9621
First edition
Space systems — Methods to decide
2024-05
thermal vacuum test cycles of
recurring production according
to precipitation efficiency and
reliability
Systèmes spatiaux — Méthodes pour déterminer les cycles
d'essais sous vide thermique de la production récurrente en
fonction de l'efficacité et de la fiabilité des précipitations
Reference number
ISO 9621:2024(en) © ISO 2024

---------------------- Page: 1 ----------------------
ISO 9621:2024(en)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2024
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.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: [phone]
Email: [e-mail]
Website: www.iso.org
Published in Switzerland

© ISO 2024 – All rights reserved
ii

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ISO 9621:2024(en)
Contents Page
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 .2
4 Methods of TVT cycles determination . 3
4.1 General .3
4.2 Failure data collection and analysis .3
4.3 Method 1 – Precipitation efficiency method .4
4.3.1 General .4
4.3.2 Precipitation efficiency estimation .5
4.4 Method 2 – Reliability method .6
4.4.1 General .6
4.4.2 Reliability method .6
4.5 Empirical equivalent fatigue exponent by failure data .7
Annex A (informative) Theory of estimating PE and its lower band limit . 9
Annex B (informative) Worked example .
...

FINAL DRAFT
International
Standard
ISO/FDIS 9621
ISO/TC 20/SC 14
Space systems — Methods to decide
Secretariat: ANSI
thermal vacuum test cycles of
Voting begins on:
recurring production according
2024-02-22
to precipitation efficiency and
Voting terminates on:
reliability
2024-04-18
Systèmes spatiaux — Méthodes pour déterminer les cycles
d'essais sous vide thermique de la production récurrente en
fonction de l'efficacité et de la fiabilité des précipitations
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
BEING ACCEPTABLE FOR INDUSTRIAL, TECHNO­
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.
Reference number
ISO/FDIS 9621:2024(en) © ISO 2024

---------------------- Page: 1 ----------------------
FINAL DRAFT
ISO/FDIS 9621:2024(en)
International
Standard
ISO/FDIS 9621
ISO/TC 20/SC 14
Space systems — Methods to decide
Secretariat: ANSI
thermal vacuum test cycles of
Voting begins on:
recurring production according
to precipitation efficiency and
Voting terminates on:
reliability
Systèmes spatiaux — Méthodes pour déterminer les cycles
d'essais sous vide thermique de la production récurrente en
fonction de l'efficacité et de la fiabilité des précipitations
RECIPIENTS OF THIS DRAFT ARE INVITED TO SUBMIT,
COPYRIGHT PROTECTED DOCUMENT
WITH THEIR COMMENTS, NOTIFICATION OF ANY
RELEVANT PATENT RIGHTS OF WHICH THEY ARE AWARE
AND TO PROVIDE SUPPOR TING DOCUMENTATION.
© ISO 2024
IN ADDITION TO THEIR EVALUATION AS
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
BEING ACCEPTABLE FOR INDUSTRIAL, TECHNO­
LOGICAL, COMMERCIAL AND USER PURPOSES, DRAFT
be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on
INTERNATIONAL STANDARDS MAY ON OCCASION HAVE
the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address below
TO BE CONSIDERED IN THE LIGHT OF THEIR POTENTIAL
or ISO’s member body in the country of the requester.
TO BECOME STAN DARDS TO WHICH REFERENCE MAY BE
MADE IN NATIONAL REGULATIONS.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: [phone]
Email: [e-mail]
Website: www.iso.org
Published in Switzerland Reference number
ISO/FDIS 9621:2024(en) © ISO 2024

© ISO 2024 – All rights reserved
ii

---------------------- Page: 2 ----------------------
ISO/FDIS 9621:2024(en)
Contents Page
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 .2
4 Methods of TVT cycles determination . 3
4.1 General .3
4.2 Failure data collection and analysis .
...

ISO/FDIS 9621:2023(E)
ISO/TC 20/SC 14/WG 2
Secretariat: ANSI/AIAA
Date: 2023-10-132024-02-06
Space systems — Methods to decide thermal vacuum test cycles of
recurring production according to precipitation efficiency and
reliability
Systèmes spatiaux — Méthodes pour déterminer les cycles d'essais sous vide thermique de la production
récurrente en fonction de l'efficacité et de la fiabilité des précipitations
FDIS stage

---------------------- Page: 1 ----------------------
ISO/FDIS 9621:2023(E2024(en)
© ISO 2023, 2024Published in Switzerland
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.
ISO copyright office
CP 401 • Ch. de Blandonnet 8 • CP 401
CH-1214 Vernier, Geneva, Switzerland
Tel.Phone: + 41 22 749 01 11
Fax + 41 22 749 09 47
E-mail: [e-mail]
Website: www.iso.org
Published in Switzerland
ii © ISO 2023 – All rights reserved
© ISO 2024 – All rights reserved

ii

---------------------- Page: 2 ----------------------
ISO/FDIS 9621:2023(E2024(en)
Contents
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 .3
4 Methods of TVT cycles determination .3
4.1 General .3
4.2 Failure data collection and analysis .4
4.3 Method 1 – Precipitation efficiency method.5
4.3.1 General .5
4.3.2 Precipitation efficiency estimation .5
4.4 Method 2 – Reliability method .7
4.4.1 General .7
4.4.2 Reliability method .7
4.5 Empirical equivalent fatigue exponent by failure data .9
Annex A (informative) Theory of estimating PE and its lower band limit . 10
Annex B (informative) Worked example . 13
...