ISO 23135:2022

INTERNATIONAL ISO
STANDARD 23135
First edition
2022-03
Space systems — Verification
programme and management process
Reference number
ISO 23135:2022(E)
© ISO 2022

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ISO 23135:2022(E)
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© ISO 2022
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Published in Switzerland
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ISO 23135:2022(E)
Contents Page
Foreword .v
Introduction . vi
1 Scope . 1
2 Normative references . 1
3 Terms and definitions and abbreviated terms . 1
3.1 Terms and definitions . 1
3.2 Abbreviated terms . 2
4 Requirements for space system verification management processes .3
4.1 General . 3
4.2 VM process 1: requirement flow-down and establishment of specification . 3
4.2.1 General . 3
4.2.2 Specification requirements and review . 4
4.2.3 Data supporting verification method and approach . 5
4.3 VM process 2: verification cross-reference matrix (VCRM) . 5
4.3.1 Cross-reference of specification requirements and verification method . 5
4.3.2 VCRM for the space system and lower level systems . 5
4.3.3 Verification by analysis . 5
4.3.4 Verification by test. 5
4.3.5 Verification by inspection and demonstration . 6
4.4 VM process 3: integration and test (I&T) process . 6
4.4.1 General . 6
4.4.2 Review of I&T plans for the space system and lower level systems . 6
4.4.3 Space system and lower-level I&T sequence and test environments . 6
4.4.4 Operational tests for space system . 6
4.4.5 Test readiness review (TRR) and entry/exit criteria . 6
4.4.6 Test discrepancy resolution and retest . 7
4.4.7 Test summary and “as tested” data review . 7
4.4.8 I&T plans for launch site operations for each element . 7
4.4.9 I&T plans for launch site operations for integrated system . 7
4.5 VM process 4: specification verification ledger (SVL) process . 7
4.5.1 General . 7
4.5.2 SVL content . 7
4.5.3 SVL documentation . 8
4.5.4 Subcontractor/vendor SVL plans for the space system element including
subsystems, and units . 8
4.6 VM process 5: acceptance and delivery review process. 8
4.6.1 General . 8
4.6.2 Space system and lower level systems acceptance and delivery review data
package . 8
4.6.3 Acceptance and delivery review plans for the systems developed by
subcontractors/vendors . 8
4.6.4 FCA and PCA summary as a part of acceptance package . 8
4.6.5 Acceptance/delivery review entry/exit criteria . 9
4.7 VM process 6: verification-related risk and issue/watch list management process . 9
4.7.1 General . 9
4.7.2 Status tracking of verification-related issue and concern items . 9
4.7.3 Reporting of verification-related issues to the programme risk
management board . 9
4.7.4 Verification-related risk and issue/watch list management plans for
the space system and lower level systems including those developed by
subcontractors/vendors . 9
5 Requirements for space systems verification programme management .9
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ISO 23135:2022(E)
5.1 General . 9
5.2 Verification programme managed by each WBS element . 9
5.3 Integration of distributed verification programme . 10
5.4 Verification programme review . 10
5.5 Verification programme flow-down to subcontractors and vendors . 10
5.6 Verification activities coordinated with other review boards . 10
5.7 Validation of the verification process . 10
5.7.1 General . 10
5.7.2 DT&E and OT&E support . 10
5.7.3 Independent readiness review (IRR) and launch readiness review (LRR)
support . 10
5.8 Verification plan . 11
5.8.1 General . 11
5.8.2 Review of verification plans . 11
6 Use of verification management for late changes and heritage/commercial systems .11
6.1 General . 11
6.2 Late change verification management . 11
6.2.1 Verification of late changes utilizing VM processes 1 through 6 . 11
6.2.2 Late change categories .12
6.3 Heritage/commercial systems verification management .12
6.3.1 General .12
6.3.2 Heritage/commercial hardware and software applications .12
6.3.3 Verification of heritage hardware and software .13
Annex A (informative) Exemplar space system and an example of WBS-based verification
management structure .14
Annex B (informative) Review of verification plans for space system and lower system
level, including those developed by subcontractors/vendors .15
Annex C (informative) Deliverable/review documents associated with each verification
management rrocess .20
Annex D (informative) Contents of specification verification ledger (SVL) .22
Annex E (normative) Recommended Check List for Planning and Executing Late Changes,
Heritage, or Commercial System Applications .24
Bibliography .28
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ISO 23135:2022(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 documents 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 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. 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 www.iso.org/patents).
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation on 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.
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ISO 23135:2022(E)
Introduction
This verification programme document provides top-tier and overarching requirements in space
programmes. Implementation will ensure thoroughly verified space systems in a timely and cost-
effective manner for verification distributed among all participating organizations (see AIAA S-117).
Many space programmes are very complex systems consisting of numerous elements (such as
spacecraft, launch and ground segments, systems, subsystems, units, interfaces). It is common for
these elements to be distributed across many international/domestic contractors, subcontractors,
and suppliers with little room for failure/mistakes in any part of a space system. This is what is
meant as a distributed program in the context of this document. A critical function of any distributed
verification programme is to ensure that a thorough and solid specification is established for each level
of a system being developed. This is accomplished if the system developer for each level contractually
takes responsibility/ownership of developing their specifications in coordination with their systems
engineering organization. This approach ensures that requirements establishment and associated
verification activities are well integrated. Additionally, cost constraints often require avoidance of
additional verification due to late changes. Lack of detailed descriptions in specifications can cause
costly late changes and/or post-launch failures. Mission success does not allow unrecoverable post-
launch failures; as such, verification of space systems requires technical communication of verification
means, data and data aggregation among all involved (system contractors, subcontractors and vendors).
This document ensures that requirements associated with space system missions, concept of operation
(mission operation concept), contractual agreed normative references as well as each contractor’s
command media are thoroughly verified with the use of a distributed verification programme. It
defines a standardized set of verification management processes for each element of a space system
from the earliest to the latest phase and from the lowest to the highest level of their developments in
order to acquire/deliver thoroughly verified systems.
The need for a distributed verification programme was identified based on the evaluation of over
130 space systems failures associated with international, commercial, and government space
programmes (see INCOSE Journal).
Every element of a space system can be verified and tracked by each work breakdown structure
based working group (WBS-WG; see ISO 21349) utilizing standardized verification management (VM)
processes as follows:
a) VM process 1: requirements flow-down and establishment of specification;
b) VM process 2: verification cross-reference matrix (VCRM);
c) VM process 3: integration and test (I&T);
d) VM process 4: use of a specification verification ledger (SVL);
e) VM process 5: acceptance/delivery reviews
f) VM process 6: verification-related risk and issue/watch list management
This document also helps each space programme to integrate any heritage/commercial systems
to new programmes by examining whether the applicability of these systems has been thoroughly
verified. Appropriate modifications of any heritage/commercial systems for new/modified systems
are systematically identified and verification accomplished by applying these uniform six verification
management processes.
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INTERNATIONAL STANDARD ISO 23135:2022(E)
Space systems — Verification programme and management
process
1 Scope
This document establishes a set of requirements for planning and executing verification programmes
for commercial/non-commercial manned and unmanned space systems.
This document defines a distributed verification programme for each contractor that engages in the
development of any element of a space system, starting from the lowest level (i.e. unit/piece part level)
and the earliest phase (i.e. requirement phase) to the acceptance and the delivery review of a system’s
development as well as the launch site activities.
This document primarily addresses verification associated with space, launch, and ground segment
acquisitions. Space support segments including range safety, ground support equipment, and launch
operation facilities, which are not otherwise addressed in this document, can also benefit from the
described verification programme and management processes.
2 Normative references
There are no normative references in this document.
3 Terms and definitions and abbreviated terms
3.1 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/
3.1.1
heritage system
system/item with from the original supplier that has maintained the great majority of the original
service, design, performance and manufacturing and has already flown in space
3.1.2
late change
change to the space, launch, ground segments, or their interfaces, procedures or processes, which
compromise or potentially invalidate previously executed verification approved at each system level
preliminary design review (PDR) and/or critical design review (CDR)
3.1.3
mission critical failure
condition that meets one or more of the following criteria:
a) failure leading to inability to meet/achieve mission objective (e.g. payload or spacecraft bus is no
longer capable of supporting the mission objectives);
b) inability to meet minimum performance specifications for primary mission;
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ISO 23135:2022(E)
c) degrading condition whose trend indicates a loss of mission before mean mission duration or
design life;
d) repetitive transient condition(s) that, uncorrected, would lead to an unacceptable loss of mission
performance, data or services (e.g. satellite with processor susceptibility to single event upsets in
orbit with mean time to upset much less than mean time to recovery from upset)
3.1.4
operational test and evaluation
test and evaluation that represents the mission in terms of phase, transitions, environments, personnel
and events in an end-to-end system configuration (i.e. combination of hardware/software and data
when functioning as an integrated system), accepting mission inputs, executing mission functions
and producing mission outputs according to the typical operational rhythm, timelines, and sequences
resulting in end-user goals (products, services, and timeliness)
3.1.5
specification verification ledger
digital database for verification information of the space system specification
3.1.6
subject matter expert
person with substantial knowledge of, and experience with, the topic at hand, including terms,
technology and methods
3.1.7
verification cross-reference matrix
matrix, usually electronic database of some type, maintained to correlate all verification needs within
an assigned portion of a program, up to and including a complete program matrix
Note 1 to entry: The matrix does not replace other verification plans or requirements, but is a summary of them.
3.1.8
verification method
method including test, analysis, demonstration, or inspection
Note 1 to entry: See ISO 9000.
3.1.9
verification record
record of requirement conformity or compliance based on the assigned verification method(s) (3.1.8)
3.2 Abbreviated terms
AIAA American Institute of Aeronautics and Astronautics
CDR critical design review
CDRL contract data requirements list
COTS commercial, off-the-shelf
CM configuration management
DT&E development test and evaluation
EM engineering module
EMC electro-magnetic compatibility
EMI electro-magnetic interference
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ISO 23135:2022(E)
FCA functional configuration audit
I&T integration and test
IF interface
LRR launch readiness review
MRR manufacturing readiness review
NRB non-conformance review board
OT&E operational test and evaluation
PCA physical configuration audit
PDR preliminary design review
PMPCB parts, materials, and processes control board
QA quality assurance
SC spacecraft
SVL specification verification ledger
SDR system design review
SRR system requirements review
TPRD test parameters requirements document
TRR test readiness review
VCRM verification cross-reference matrix
VM verification management
WC worst-case
WBS work breakdown structure
WBS-WG WBS-based working group
4 Requirements for space system verification management processes
4.1 General
Each space system and lower-level systems developer shall implement the verification processes
detailed in 4.2 through 4.7. To better support a specific programme or project, the processes defined in
this document may be tailored to match the actual requirements or needs of the programme.
4.2 VM process 1: requirement flow-down and establishment of specification
4.2.1 General
The developers of each level of the system, in coordination with their systems engineering organizations,
develop a system-level specification with both performance and verification requirements for their
system. They capture the requirements that are flowed down from the top-level space system to
WBS elements, external interface specifications, and concept of operations (CONOPS) of their system.
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ISO 23135:2022(E)
They capture all the derived and specific requirements including those of normative references that
are necessary to design and develop their system. They also capture/modify all the heritage system
requirements that are compatible with the top-level requirements determined by the requirements
flow-up process.
Each specification shall include sections relating to:
a) the function, performance, constraints, and normative references for the product;
b) a detailed statement of how verification will be made for each separate requirement.
This includes verification methods and associated verification approaches.
NOTE 1 Specifications are defined in ISO 9000.
NOTE 2 See ISO/IEC/IEEE 15288 for flow-down and flow-up in the systems engineering “V”.
NOTE 3 See ISO 16404 for general requirement management process including those associated with support
to systems engineering activities such as those associated with verification and configuration management.
NOTE 4 See ISO 14711 for CONOPS-related documents.
4.2.2 Specification requirements and review
4.2.2.1 General
Specifications shall be delivered for review at each corresponding system level’s review from the top
system level to the lowest unit level specification [e.g. system requirements review (SRR), system
design review (SDR), preliminary design review (PDR), critical design review (CDR)].
NOTE See ISO 14300-1 for project phasing and reviews.
4.2.2.2 Top-level requirements flowed-down/up documented traceability
Each of the top space system level requirements flowed down/up shall have documented traceability in
the verification record to the lowest level of the work breakdown structure (WBS).
4.2.2.3 Verification of non-derived requirements specific to each system
Verification requirements shall capture all the non-derived requirements that are specific to each of
the elements being developed.
NOTE Non-derived requirements are requirements which do not have a parent requirement in the next
higher level, such as those that are needed to satisfy heritage systems.
4.2.2.4 Verification of compatibility of heritage systems requirements
When heritage systems are used, verification requirements shall ensure that each of the requirements
in the heritage system specification is compatible with and supports the higher- and lower-level system
requirements. If not, they need to modify any noncompliant requirements accordingly (see ISO 16290).
4.2.2.5 Requirement verifiability
Each of the requirements shall be verifiable by analysis, test, inspection or demonstration or a
combination of them (see ISO 9000).
4.2.2.6 Normative references flow-down
Each of the normative references listed at any system level shall also be flowed down from the
appropriate level specification to any of the applicable lower level specifications.
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ISO 23135:2022(E)
4.2.2.7 Configuration management (CM)
The system level requirements shall be under CM control upon completion of SRR.
Lower level requirements shall be under CM control upon completion of PDR.
The requirements flow-down and flow-up efforts should be accomplished by utilizing data management
software in order to effectively manage any part of system level requirements flowed down/up to/from
any other system levels.
Validation of the developed specification may be considered as completed after independent subject
matter experts from external organizations have reviewed the specification and their comments are
incorporated into the specification.
4.2.3 Data supporting verification method and approach
Each specification ver
...