SIST-TP CEN/CLC/TR 17603-11:2021

Space engineering - Technology readiness level (TRL) guidelines

The present handbook is provided to support the implementation of the requirements of ECSS-E-AS-11 to space projects.
With this purpose, this handbook provides guidelines on the w ay to assess the maturity of a technology of a product in a
given environment, to use the TRL assessment outcome in the product development framew ork, and to introduce some
further refinements for specific disciplines or products to w hich the TRL assessment methodology can be extended.
The concept of Manufacturing Readiness Level (MRL) is not addressed in this document, w hilst the concept of TRL can
be applied to the technology-related aspects of manufacturing.

Raumfahrttechnik - Richtlinien zum technischen Reifegrad (TRL)

Ingénierie spatiale - Guide d’utilisation des Niveaux de Maturité Technologique (NMT)

Vesoljska tehnika - Smernice za ravni tehnološke zrelosti (TRL)

General Information

• Status: Published
• Public Enquiry End Date: 24-Feb-2021
• Publication Date: 10-Oct-2021
• ICS: 49.140 - Space systems and operations
• Technical Committee: I13 - Imaginarni 13
• Current Stage: 6060 - National Implementation/Publication (Adopted Project)
• Start Date: 06-Oct-2021
• Due Date: 11-Dec-2021
• Completion Date: 11-Oct-2021
• Mandate: M/496 - Mandate addressed to CEN, CENELEC and ETSI to develop standardisation regarding space industry (Phase 3 of the process)
• Ref Project: CEN/CLC/TR 17603-11:2021 - Space engineering - Technology readiness level (TRL) guidelines

Standards Content (Sample)

SLOVENSKI STANDARD
SIST-TP CEN/CLC/TR 17603-11:2021
01-november-2021
Vesoljska tehnika - Smernice za ravni tehnološke zrelosti (TRL)
Space engineering - Technology readiness level (TRL) guidelines
Raumfahrttechnik - Richtlinien zum technischen Reifegrad (TRL)
Ingénierie spatiale - Guide d’utilisation des Niveaux de Maturité Technologique (NMT)
Ta slovenski standard je istoveten z: CEN/CLC/TR 17603-11:2021
ICS:
49.140 Vesoljski sistemi in operacije Space systems and
operations
SIST-TP CEN/CLC/TR 17603-11:2021 en,fr,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

---------------------- Page: 1 ----------------------
SIST-TP CEN/CLC/TR 17603-11:2021

---------------------- Page: 2 ----------------------
SIST-TP CEN/CLC/TR 17603-11:2021


TECHNICAL REPORT
CEN/CLC/TR 17603-11

RAPPORT TECHNIQUE

TECHNISCHER BERICHT
September 2021
ICS 49.140

English version

Space engineering - Technology readiness level (TRL)
guidelines
Ingénierie spatiale - Guide d'utilisation des Niveaux de Raumfahrttechnik - Richtlinien zum technischen
Maturité Technologique (NMT) Reifegrad (TRL)


This Technical Report was approved by CEN on 26 March 2021. It has been drawn up by the Technical Committee CEN/CLC/JTC
5.

CEN and CENELEC members are the national standards bodies and national electrotechnical committees of Austria, Belgium,
Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy,
Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Republic of North Macedonia, Romania, Serbia,
Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and United Kingdom.
























CEN-CENELEC Management Centre:
Rue de la Science 23, B-1040 Brussels
© 2021 CEN/CENELEC All rights of exploitation in any form and by any means Ref. No. CEN/CLC/TR 17603-11:2021 E
reserved worldwide for CEN national Members and for
CENELEC Members.

---------------------- Page: 3 ----------------------
SIST-TP CEN/CLC/TR 17603-11:2021
CEN/CLC/TR 17603-11:2021 (E)
Table of contents
European Foreword . 5
Introduction . 6
1 Scope . 7
2 References . 8
3 Terms, definitions and abbreviated terms . 10
3.1 Terms defined in other documents . 10
3.2 Terms specific to the present document . 11
3.3 Abbreviated terms and symbols . 11
4 TRL history and evolution . 13
4.1 History and evolution . 13
4.2 Differences between M95r and ISO 16290 standard as seen by ECSS
(European interpretation) . 13
4.3 TRL implementation in ECSS system . 14
4.4 TRL and assessment basic principles . 14
5 Technology readiness assessment (TRA) guidelines . 17
5.1 Introduction . 17
5.2 General principles for technology readiness assessment. 17
5.2.1 TRL standard . 17
5.2.2 TRA pre-requisites . 21
5.2.3 Independent verification of the TRL . 22
5.2.4 Discipline specific TRA process . 22
5.2.5 Typical technology readiness assessment (TRA) process. 22
5.2.6 TRA criteria . 23
5.2.7 Viability of TRL progression . 23
5.3 TRL evaluation by level . 24
5.3.1 TRL 1: Basic principles observed and reported . 24
5.3.2 TRL 2: Technology concept and/or application formulated . 24
5.3.3 TRL 3: Analytical and experimental critical function and/or
characteristic proof-of-concept . 24
2

---------------------- Page: 4 ----------------------
SIST-TP CEN/CLC/TR 17603-11:2021
CEN/CLC/TR 17603-11:2021 (E)
5.3.4 TRL 4 : Component and/or breadboard functional verification in
laboratory environment . 25
5.3.5 TRL 5 : Component and/or breadboard critical function verification in
a relevant environment . 26
5.3.6 TRL 6: Model demonstrating the critical functions of the element in a
relevant environment . 27
5.3.7 TRL 7 : Model demonstrating the element performance for the
operational environment . 28
5.3.8 TRL 8 : Actual system completed and accepted for flight (“flight
qualified”) . 28
5.3.9 TRL 9: Actual system “flight proven” through successful mission
operations . 29
5.4 Guidelines for other uses of TRLs in R&T&D activities . 29
6 Implementation in projects . 32
6.1 General . 32
6.2 Critical functions and technologies in projects . 33
6.2.1 Overview . 33
6.2.2 Technology readiness status list (TRSL) and transference to critical
item list . 34
6.3 Technology readiness assessment (TRA) in projects . 34
6.4 Typical levels linked to project phases and milestones . 35
7 Links with model philosophy and technology demonstration and
reassessment . 39
7.1 Links with model types and technology demonstration . 39
7.1.1 Link between TRL and model types . 39
7.1.2 Link between TRL and technology demonstrators . 42
7.2 Re-assessment of TRL for re-use of element with existing TRA . 44
7.2.1 Technical guidelines . 44
7.2.2 Technology re-use in a new environment . 46
Annex A TRL considerations for software . 47
A.1 Terms specific to the present annex . 47
A.2 ISO TRL scale and software developments . 48
A.3 Basic principles . 48
A.4 Use of TRL with Software . 49
A.5 Relationship between TRL and criticality categories . 56
Annex B TRL considerations for EEE components . 57
Annex C TRL considerations for materials and manufacturing processes . 59

3

---------------------- Page: 5 ----------------------
SIST-TP CEN/CLC/TR 17603-11:2021
CEN/CLC/TR 17603-11:2021 (E)
Figures
Figure 4-1: Illustration of differences between M95r (European interpretation) and
ECSS-E-AS-11. 14
Figure 4-2: Evolution technology maturity . 15
Figure 5-1: Illustration of a new RF transistor then RF amplifier progressing through
TRL . 21
Figure 5-2: Example of ESA technology activity template . 30
Figure 5-3: Illustration of a Technology Roadmap . 31
Figure 6-1: Risk versus TRL and complexity . 33
Figure 6-2: Evolution of technology options during preliminary project phases . 35
Figure 6-3: Project phases and generalised institutional expectation of TRA outcome . 37
Figure 6-4: Project phases and generalised commercial expectation of TRA outcome . 38

Tables
Table 5-1: TRL summary - Milestones and work achievement (adapted from ISO
16290) . 18
Table 6-1: Benefits of use of TRA . 36
Table 7-1: Models types associated to TRLs . 40
Table 7-2: Use of commonly-used models for TRL progression . 42
Table 7-3: Links between TRL and Heritage Category . 45
Table 7-4: Technology maturity transfer for re-use . 46

Table A-1 : Link between Software development status and TRL . 50
Table B-1 : Milestones and work achievement for EEE components TRL. 57
Table C-1 : Use of TRL for with materials and manufacturing process development . 60


4

---------------------- Page: 6 ----------------------
SIST-TP CEN/CLC/TR 17603-11:2021
CEN/CLC/TR 17603-11:2021 (E)
European Foreword
This document (CEN/CLC/TR 17603-11:2021) has been prepared by Technical Committee
CEN/CLC/JTC 5 “Space”, the secretariat of which is held by DIN.
It is highlighted that this technical report does not contain any requirement but only collection of data
or descriptions and guidelines about how to organize and perform the work in support of EN 16603-
11.
This Technical report (CEN/CLC/TR 17603-11:2021) originates from ECSS-E-HB-11A.
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CEN [and/or CENELEC] shall not be held responsible for identifying any or all such
patent rights.
This document has been prepared under a mandate given to CEN by the European Commission and
the European Free Trade Association.
This document has been developed to cover specifically space systems and has therefore precedence
over any TR covering the same scope but with a wider domain of applicability (e.g.: aerospace).

5

---------------------- Page: 7 ----------------------
SIST-TP CEN/CLC/TR 17603-11:2021
CEN/CLC/TR 17603-11:2021 (E)
Introduction
This Handbook supports the application of the TRL, and provides guidelines to its use in projects and
its independent verification within each specific project context.
This Handbook provides guidelines for best practice for interpretation of the requirements contained
in ECSS-E-AS-11 and for the implementation of the process of technology readiness assessment for
technologies applied to a critical function of an element.
The ECSS-E-AS-11 - “Adoption Notice of ISO 16290 Definition of the Technology Readiness Levels
(TRLs) and their criteria of assessment” adopts ISO 16290 with a minimum set of modifications, to
allow for reference and for a consistent integration in ECSS system of standards.
TRL is a scale for technology maturity assessment and not a method of technology engineering nor
development. TRL is used in R&T&D activities and also in project activities.
For project activities, a technology readiness assessment informs the project manager (until the end of
B phase) of the risk when adopting a new technology for a critical function of an element of the
system. In the C and D phases TRL is no longer used by the project and the maturity of technology is
managed in the critical item list.
For other projects the information of the declared technology maturity can be reused and an
assessment of the new project use conditions are considered in the assessment.
In this handbook the three main actors and the respective role of each actor are clearly identified. The
three discrete actors are: technology developers, projects teams (using the technology) and the TRA
participants (i.e. those who perform the technology readiness assessment).
6

---------------------- Page: 8 ----------------------
SIST-TP CEN/CLC/TR 17603-11:2021
CEN/CLC/TR 17603-11:2021 (E)
1
Scope
The present handbook is provided to support the implementation of the requirements of ECSS-E-AS-11
to space projects.
With this purpose, this handbook provides guidelines on the way to assess the maturity of a
technology of a product in a given environment, to use the TRL assessment outcome in the product
development framework, and to introduce some further refinements for specific disciplines or
products to which the TRL assessment methodology can be extended.
The concept of Manufacturing Readiness Level (MRL) is not addressed in this document, whilst the
concept of TRL can be applied to the technology-related aspects of manufacturing.
7

---------------------- Page: 9 ----------------------
SIST-TP CEN/CLC/TR 17603-11:2021
CEN/CLC/TR 17603-11:2021 (E)
2
References
The following documents are referenced in this text or provide additional information useful for the
reader.

EN Reference Reference in text Title
EN 16601-00-01 ECSS-S-ST-00-01 ECSS system – Glossary of terms
EN 16603-10 ECSS-E-ST-10 Space engineering – System engineering general
requirements
EN 16603-10-02 ECSS-E-ST-10-02 Space engineering – Verification
EN 16603-10-03 ECSS-E-ST-10-03 Space engineering – Testing
EN 16603-10-06 ECSS-E-ST-10-06 Space engineering – Technical requirements
specification
EN 16603-10-24 ECSS-E-ST-10-24 Space engineering – Interface management
EN 16603-11 ECSS-E-AS-11 Adoption notice of ISO 16290, Space systems –
Definition of the Technology Readiness Levels (TRLs)
and their criteria of assessment (1 October 2014)
TR 17603-10-02 ECSS-E-HB-10-02 Space engineering – Verification guidelines
EN 16603-40 ECSS-E-ST-40 Space engineering – Software
EN 16603-70 ECSS-E-ST-70 Space engineering – Ground systems and operations
EN 16601-10-10 ECSS-M-ST-10-01 Space project management – Organization and
conduct of reviews
EN 16601-60 ECSS-M-ST-60 Space project management – Cost and schedule
management
EN 16601-80 ECSS-M-ST-80 Space project management – Risk management
EN 16602-10 ECSS-Q-ST-10 Space product assurance – Product assurance
management
EN 16602-10-04 ECSS-Q-ST-10-04 Space product assurance – Critical-item control
EN 16602-20 ECSS-Q-ST-20 Space product assurance – Quality assurance
EN 16602-20-10 ECSS-Q-ST-20-10 Space product assurance – Off-the-shelf items
utilization in space systems
EN 16602-30 ECSS-Q-ST-30 Space product assurance – Dependability
EN 16602-40 ECSS-Q-ST-40 Space product assurance - Safety
EN 16602-60 ECSS-Q-ST-60 Space product assurance – Electrical, electronic and
electromechanical (EEE) components
8

---------------------- Page: 10 ----------------------
SIST-TP CEN/CLC/TR 17603-11:2021
CEN/CLC/TR 17603-11:2021 (E)
EN Reference Reference in text Title
EN 16602-60-13 ECSS-Q-ST-60-13 Space product assurance – Commercial electrical,
electronic and electromechanical (EEE) components
EN 16602-70 ECSS-Q-ST-70 Space product assurance – Materials, mechanical parts
and processes
EN 16602-70-71 ECSS-Q-ST-70-71 Spaced product assurance – Materials, processes and
their data selection
EN 16602-80 ECSS-Q-ST-80 Space product assurance – Software product assurance
ISO 16290:2013 Space systems - Definition of the Technology
Readiness Levels (TRLs) and their criteria of
assessment
Mankins 95 reference TECHNOLOGY READINESS LEVELS, A White
(M95r) Paper, April 6, 1995, John C. Mankins Advanced
Concepts Office, Office of Space Access and
Technology NASA 1
https://www.hq.nasa.gov/office/codeq/trl/trl.pdf

9

---------------------- Page: 11 ----------------------
SIST-TP CEN/CLC/TR 17603-11:2021
CEN/CLC/TR 17603-11:2021 (E)
3
Terms, definitions and abbreviated terms
3.1 Terms defined in other documents
a. For the purpose of this document, the terms and definitions from ECSS-E-AS-11 apply, in
particular for the following terms:
1. critical function of an element
NOTE The synonym of “critical function” is “critical function of an element”.
2. element
NOTE It is important to realize that the term element has a different meaning in
ECSS-E-AS-11 (that refer to ISO 16290) than in the ECSS Glossary of
terms (ECSS-S-ST-00-02). This guidelines use the term element as defined
in ISO 16290.
3. breadboard
4. laboratory environment
5. mature technology
6. operational environment
7. relevant environment
8. reproducible process
9. validation
b. For the purpose of this document the terms from ECSS-S-ST-00-01, except the terms listed in
3.1a apply, in particular for the following terms:
1. commissioning result review
2. component (context EEE)
NOTE For TRL 4 and TRL 5 the term “component” is understood as “part of a
larger whole”.
3. environment
4. ground segment
5. technology readiness level
c. For the purpose of this document the terms from ECSS-E-ST-70, except the terms listed in 3.1a.
and 3.1b apply, in particular for the following term:
1. Ground Segment QR (GSQR)
2. Operations QR (OQR)
3. Software Requirement Specification (SRS)
10

---------------------- Page: 12 ----------------------
SIST-TP CEN/CLC/TR 17603-11:2021
CEN/CLC/TR 17603-11:2021 (E)
3.2 Terms specific to the present document
3.2.1 Research and Technology and Development (R&T&D)
activities to mature from research to technology to development as they are progressing from lower to
high TRL levels
3.3 Abbreviated terms and symbols
For the purpose of this document, the abbreviated terms from ECSS-S-ST-00-01 and the following
apply:
Abbreviation Meaning
acceptance review
AR
critical design review
CDR
commissioning readiness review
CRR
critical item list
CIL
development model
DM
displacement damage
DD
electrical, electronic and electromechanical
EEE
engineering model
EM
electromagnetic compatibility
EMC
engineering qualification model
EQM
equipment qualification status review
EQSR
European Space Components Coordination
ESCC
flight model
FM
In-orbit operations review
IOOR
International Standardization Organization
ISO
invitation to tender
ITT
Launch and early orbit phase
LEOP
Mankins 95 reference
M95r
mission definition review
MDR
National Aeronautics and Space Administration
NASA
new work item proposal
NWIP
Product Assurance
PA
printed circuit board
PCB
preliminary design review
PDR
protoflight model
PFM
proof of concept
POC
preliminary requirements review
PRR
qualification model
QM
11

---------------------- Page: 13 ----------------------
SIST-TP CEN/CLC/TR 17603-11:2021
CEN/CLC/TR 17603-11:2021 (E)
Abbreviation Meaning
quality management system
QMS
qualification review
QR
reliability, availability, maintainability and safety
RAMS
radiofrequency
RF
Research and Technology and Development
R&T&D
single event effect
SEE
single event latch-up
SEL
structural model
SM
software problem report
SPR
software reuse file
SRF
structural thermal model
STM
total ionising dose
TID
thermal model
TM
terms of reference
ToR
technology plan
TP
technology readiness assessment
TRA
technology readiness level
TRL
technology readiness status list
TRSL
verification and validation
V&V
working group
WG
with respect to
w.r.t.

12

---------------------- Page: 14 ----------------------
SIST-TP CEN/CLC/TR 17603-11:2021
CEN/CLC/TR 17603-11:2021 (E)
4
TRL history and evolution
4.1 History and evolution
The TRL methodology was originated at NASA in the 1970s in order to establish a method by which
NASA selected new technology amongst numerous candidates for their complex spaceflight
programmes. The scale progressed until 1995 with the definition of nine levels that became the
Mankins 95 reference (M95r) [see clause2]. From that moment, the principle of a maturity scale was
adopted by many companies and government agencies around the world. However, although they
were somewhat similar, different definitions or interpretation of the M95r were used. ECSS decided,
in 2008, to first make a harmonization at European level and then to propose to ISO a global
harmonization in 2009. This then resulted in an ISO New Work Item Proposal (NWIP) “Definition of
the Technology Readiness Levels (TRLs) and their criteria of assessment”.
The ISO standard 16290 was published in 2013 and as a result, TRL are now globally harmonized.
ECSS actively contributed to this ISO standard by providing members to the ISO WG. The ISO
standard concerns the definition and the criteria of assessment, however the procedure for the TRL
assessment or the way to use them within a project’s framework was not the purpose of the standard.
The standard is applicable primarily to space system hardware, although the definitions are used in a
wider domain in many cases.
It is important to recognise that the ISO standard introduces some modifications with regards to the
M95r previous interpretation in ECSS documents.
4.2 Differences between M95r and ISO 16290 standard
as seen by ECSS (European interpretation)
Below is given a summary of the differences between M95r and ISO 16290 standard, supported by
Figure 4-1:
• ISO levels 1, 2, 3 and 4 definitions are equivalent to M95r (see clause 2) .
• ISO level 5 is a new intermediate level defined for when breadboards at sub-scales are used (the
breadboards used to demonstrate the critical function in a relevant environment are not full
scale or full function representations of the flight equipment).
• ISO level 6 is equivalent to M95r level 5.
• ISO level 7 is equivalent to M95r level 6.
• ISO does not recognize M95r level 7 which was “System prototype demonstration in space
environment”.
• ISO levels 8 and 9 are equivalent to M95r definitions respectively defining “flight qualified”
(qualified for flight) and “flight proven” for the actual systems.
Differences between M95r and ISO are summed up in Figure 4-1.
13

---------------------- Page: 15 ----------------------
SIST-TP CEN/CLC/TR 17603-11:2021
CEN/CLC/TR 17603-11:2021 (E)
Mankins 95 reference ISO 16290 standard
TRL 1 Basic principles observed and reported Basic principles observed and reported
Equivalent
TRL 2 Technology concept and/or application formulated Technology concept and/or application formulated
Equivalent
TRL 3 Analytical and experimental critical function and/or Analytical and experimental critical function and/or
Equivalent
characteristic proof-ofconcept characteristic proof-ofconcept
TRL 4 Component and/or breadboard validation in Component and/or breadboard functional verification
Equivalent
laboratory environment in laboratory environment
TRL 5 Component and/or breadboard validation in relevant Component and/or breadboard critical function
 Split
environment verification in a relevant environment
TRL 6 System/subsystem model or prototype demonstration Model demonstrating the critical functions of the
 Shifted
in a relevant environment (ground or space) element in a relevant environment
TRL 7 System prototype demonstration in a space Model demonstrating the element performance for the
 Removed
environment operational environment
TRL 8 Actual system completed and “flight qualified” Actual system completed and accepted for flight
Equivalent
through test and demonstration (ground or space) (“flight qualified”)
TRL 9 Actual system “flight proven” through successful Actual system “flight proven” through successful
Equivalent
mission operations mission operations

Figure 4-1: Illustration of differences between M95r (European interpretation) and
ECSS-E-AS-11
The M95r scale is now obsolete and for the remainder of this handbook, the term TRL is referring to
ECSS-E-AS-11 definition.
4.3 TRL implementation in ECSS system
TRL are implemented in ECSS system following four ways:
1. adoption of the ISO 16290 with an Adoption Notice (AN ref ECSS-E-AS-11),
2. introduction in the ECSS standards of the reference to the AN when TRL are used,
3. introduction in the ECSS standards of the requirements to manage the use of TRL,
4. provision of guidelines in this handbook.
The adoption notice ECSS-E-AS-11 was necessary to provide a concise method of introducing the ISO
standard in ECSS system. The AN was needed to make normative the TRL following ECSS editorial
rules, to align the terms definition and to make reference when necessary to ECSS type of reviews.
This handbook provides guidelines on the way to assess a product, to use the TRL assessment
outcome in the product and project development framework, and to introduce some refinements for
specific disciplines or products.
4.4 TRL and assessment basic principles
Technology readiness assessment (TRA, see clause 5) allows for the assignment of a measure of the
maturity of a technology. It is important to make clear that undertaking a TRA is not a method to
develop technologies. The way to develop, to test, to qualify or to verify the development cycle of
products, or the model philosophy defined by projects, are not the object of TRL but the purpose of
others discipline-specific ECSS standards and handbooks.
The measure provided by TRL assessment is valid for a given element, at a given point in time, and a
given defined environment. It changes if the conditions (such as operational environment) that
14

---------------------- Page: 16 ----------------------
SIST-TP CEN/CLC/TR 17603-11:2021
CEN/CLC/TR 17603-11:2021 (E)
prevailed at the time of the assessment are no longer valid. Such a situation leads to TRL reassessment
and re-grading, which can occur in particular when the re-build or re-use of an element is envisioned
with variation in the design, development process, targeted environment or operations.
During Research and Development, or Research and Technology (R&T&D) activities, TRL can be used
by the specialists developing the technologies to present their development plans (e.g. technology
roadmaps) and to communicate with non-specialists or project managers, the costs or risks involved in
taking particular technology choices with different TRLs.
In the framework of projects, TRL is used during preliminary phases (0, A, B) as a tool supporting the
decision whether or not to use or integrate specific technology in a space mission, and allowing such
decision to be taken with sufficient knowledge of any risk relating to the degree of maturity.
Generally R&T&D programs push (“research push”) the technologies maturity as far as the
intermediate TRLs. Projects then pull some technologies and develop these to the higher levels of
maturity.
The intermediate levels of maturity (typically TRLs 4, 5 and 6) are sometimes called “valley of death”
since some technologies are developed until TRL 4 or below, however they are not developed beyond
this achieved level (i.e. in the absence of a project “pull”), noting that projects are normally interested
in TRL 6 or above (see Figure 4-2).
The costs associated with a specific technology achieving a higher level of TRL are generally
increasing with each level attained.

Figure 4-2: Evolution technology maturity
15

---------------------- Page: 17 ----------------------
SIST-TP CEN/CLC/TR 17603-11:2021
CEN/CLC/TR 17603-11:2021 (E)
It is important to highlight the following aspects in
...

SLOVENSKI STANDARD
kSIST-TP FprCEN/CLC/TR 17603-11:2021
01-februar-2021
Vesoljska tehnika - Smernice za ravni tehnološke zrelosti (TRL)
Space engineering - Technology readiness level (TRL) guidelines
Raumfahrttechnik - Richtlinien zum technischen Reifegrad (TRL)
Ingénierie spatiale - Lignes directrices pour les niveaux de maturité technologique (TRL)
Ta slovenski standard je istoveten z: FprCEN/CLC/TR 17603-11
ICS:
49.140 Vesoljski sistemi in operacije Space systems and
operations
kSIST-TP FprCEN/CLC/TR 17603- en,fr,de
11:2021
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

---------------------- Page: 1 ----------------------
kSIST-TP FprCEN/CLC/TR 17603-11:2021

---------------------- Page: 2 ----------------------
kSIST-TP FprCEN/CLC/TR 17603-11:2021


TECHNICAL REPORT
FINAL DRAFT
FprCEN/CLC/TR 17603-
RAPPORT TECHNIQUE
11
TECHNISCHER BERICHT


December 2020
ICS 49.140

English version

Space engineering - Technology readiness level (TRL)
guidelines
Ingénierie spatiale - Lignes directrices pour les niveaux Raumfahrttechnik - Richtlinien zum technischen
de maturité technologique (TRL) Reifegrad (TRL)


This draft Technical Report is submitted to CEN members for Vote. It has been drawn up by the Technical Committee
CEN/CLC/JTC 5.

CEN and CENELEC members are the national standards bodies and national electrotechnical committees of Austria, Belgium,
Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy,
Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Republic of North Macedonia, Romania, Serbia,
Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and United Kingdom.

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.

Warning : This document is not a Technical Report. It is distributed for review and comments. It is subject to change without
notice and shall not be referred to as a Technical Report.




















CEN-CENELEC Management Centre:
Rue de la Science 23, B-1040 Brussels
© 2020 CEN/CENELEC All rights of exploitation in any form and by any means Ref. No. FprCEN/CLC/TR 17603-11:2020 E
reserved worldwide for CEN national Members and for
CENELEC Members.

---------------------- Page: 3 ----------------------
kSIST-TP FprCEN/CLC/TR 17603-11:2021
FprCEN/CLC/TR 17603-11:2020 (E)
Table of contents
European Foreword . 5
Introduction . 6
1 Scope . 7
2 References . 8
3 Terms, definitions and abbreviated terms . 10
3.1 Terms defined in other documents . 10
3.2 Terms specific to the present document . 11
3.3 Abbreviated terms and symbols . 11
4 TRL history and evolution . 13
4.1 History and evolution . 13
4.2 Differences between M95r and ISO 16290 standard as seen by ECSS
(European interpretation) . 13
4.3 TRL implementation in ECSS system . 14
4.4 TRL and assessment basic principles . 14
5 Technology readiness assessment (TRA) guidelines . 17
5.1 Introduction . 17
5.2 General principles for technology readiness assessment. 17
5.2.1 TRL standard . 17
5.2.2 TRA pre-requisites . 21
5.2.3 Independent verification of the TRL . 22
5.2.4 Discipline specific TRA process . 22
5.2.5 Typical technology readiness assessment (TRA) process. 22
5.2.6 TRA criteria . 23
5.2.7 Viability of TRL progression . 23
5.3 TRL evaluation by level . 24
5.3.1 TRL 1: Basic principles observed and reported . 24
5.3.2 TRL 2: Technology concept and/or application formulated . 24
5.3.3 TRL 3: Analytical and experimental critical function and/or
characteristic proof-of-concept . 24
2

---------------------- Page: 4 ----------------------
kSIST-TP FprCEN/CLC/TR 17603-11:2021
FprCEN/CLC/TR 17603-11:2020 (E)
5.3.4 TRL 4 : Component and/or breadboard functional verification in
laboratory environment . 25
5.3.5 TRL 5 : Component and/or breadboard critical function verification in
a relevant environment . 26
5.3.6 TRL 6: Model demonstrating the critical functions of the element in a
relevant environment . 27
5.3.7 TRL 7 : Model demonstrating the element performance for the
operational environment . 28
5.3.8 TRL 8 : Actual system completed and accepted for flight (“flight
qualified”) . 28
5.3.9 TRL 9: Actual system “flight proven” through successful mission
operations . 29
5.4 Guidelines for other uses of TRLs in R&T&D activities . 29
6 Implementation in projects . 32
6.1 General . 32
6.2 Critical functions and technologies in projects . 33
6.2.1 Overview . 33
6.2.2 Technology readiness status list (TRSL) and transference to critical
item list . 34
6.3 Technology readiness assessment (TRA) in projects . 34
6.4 Typical levels linked to project phases and milestones . 35
7 Links with model philosophy and technology demonstration and
reassessment . 39
7.1 Links with model types and technology demonstration . 39
7.1.1 Link between TRL and model types . 39
7.1.2 Link between TRL and technology demonstrators . 42
7.2 Re-assessment of TRL for re-use of element with existing TRA . 44
7.2.1 Technical guidelines . 44
7.2.2 Technology re-use in a new environment . 46
Annex A TRL considerations for software . 47
A.1 Terms specific to the present annex . 47
A.2 ISO TRL scale and software developments . 48
A.3 Basic principles . 48
A.4 Use of TRL with Software . 49
A.5 Relationship between TRL and criticality categories . 56
Annex B TRL considerations for EEE components . 57
Annex C TRL considerations for materials and manufacturing processes . 59

3

---------------------- Page: 5 ----------------------
kSIST-TP FprCEN/CLC/TR 17603-11:2021
FprCEN/CLC/TR 17603-11:2020 (E)
Figures
Figure 4-1: Illustration of differences between M95r (European interpretation) and
ECSS-E-AS-11. 14
Figure 4-2: Evolution technology maturity . 15
Figure 5-1: Illustration of a new RF transistor then RF amplifier progressing through
TRL . 21
Figure 5-2: Example of ESA technology activity template . 30
Figure 5-3: Illustration of a Technology Roadmap . 31
Figure 6-1: Risk versus TRL and complexity . 33
Figure 6-2: Evolution of technology options during preliminary project phases . 35
Figure 6-3: Project phases and generalised institutional expectation of TRA outcome . 37
Figure 6-4: Project phases and generalised commercial expectation of TRA outcome . 38

Tables
Table 5-1: TRL summary - Milestones and work achievement (adapted from ISO
16290) . 18
Table 6-1: Benefits of use of TRA . 36
Table 7-1: Models types associated to TRLs . 40
Table 7-2: Use of commonly-used models for TRL progression . 42
Table 7-3: Links between TRL and Heritage Category . 45
Table 7-4: Technology maturity transfer for re-use . 46

Table A-1 : Link between Software development status and TRL . 50
Table B-1 : Milestones and work achievement for EEE components TRL. 57
Table C-1 : Use of TRL for with materials and manufacturing process development . 60


4

---------------------- Page: 6 ----------------------
kSIST-TP FprCEN/CLC/TR 17603-11:2021
FprCEN/CLC/TR 17603-11:2020 (E)
European Foreword
This document (FprCEN/CLC/TR 17603-11:2020) has been prepared by Technical Committee
CEN/CLC/JTC 5 “Space”, the secretariat of which is held by DIN.
This document is currently submitted to the Technical Committee Approval.
It is highlighted that this technical report does not contain any requirement but only collection of data
or descriptions and guidelines about how to organize and perform the work in support of EN 16603-
11.
This Technical report (FprCEN/CLC/TR 17603-11:2020) originates from ECSS-E-HB-11A.
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CEN [and/or CENELEC] shall not be held responsible for identifying any or all such
patent rights.
This document has been prepared under a mandate given to CEN by the European Commission and
the European Free Trade Association.
This document has been developed to cover specifically space systems and has therefore precedence
over any TR covering the same scope but with a wider domain of applicability (e.g.: aerospace).
This document is currently submitted to the CEN CONSULTATION.

5

---------------------- Page: 7 ----------------------
kSIST-TP FprCEN/CLC/TR 17603-11:2021
FprCEN/CLC/TR 17603-11:2020 (E)
Introduction
This Handbook supports the application of the TRL, and provides guidelines to its use in projects and
its independent verification within each specific project context.
This Handbook provides guidelines for best practice for interpretation of the requirements contained
in ECSS-E-AS-11 and for the implementation of the process of technology readiness assessment for
technologies applied to a critical function of an element.
The ECSS-E-AS-11 - “Adoption Notice of ISO 16290 Definition of the Technology Readiness Levels
(TRLs) and their criteria of assessment” adopts ISO 16290 with a minimum set of modifications, to
allow for reference and for a consistent integration in ECSS system of standards.
TRL is a scale for technology maturity assessment and not a method of technology engineering nor
development. TRL is used in R&T&D activities and also in project activities.
For project activities, a technology readiness assessment informs the project manager (until the end of
B phase) of the risk when adopting a new technology for a critical function of an element of the
system. In the C and D phases TRL is no longer used by the project and the maturity of technology is
managed in the critical item list.
For other projects the information of the declared technology maturity can be reused and an
assessment of the new project use conditions are considered in the assessment.
In this handbook the three main actors and the respective role of each actor are clearly identified. The
three discrete actors are: technology developers, projects teams (using the technology) and the TRA
participants (i.e. those who perform the technology readiness assessment).
6

---------------------- Page: 8 ----------------------
kSIST-TP FprCEN/CLC/TR 17603-11:2021
FprCEN/CLC/TR 17603-11:2020 (E)
1
Scope
The present handbook is provided to support the implementation of the requirements of ECSS-E-AS-11
to space projects.
With this purpose, this handbook provides guidelines on the way to assess the maturity of a
technology of a product in a given environment, to use the TRL assessment outcome in the product
development framework, and to introduce some further refinements for specific disciplines or
products to which the TRL assessment methodology can be extended.
The concept of Manufacturing Readiness Level (MRL) is not addressed in this document, whilst the
concept of TRL can be applied to the technology-related aspects of manufacturing.
7

---------------------- Page: 9 ----------------------
kSIST-TP FprCEN/CLC/TR 17603-11:2021
FprCEN/CLC/TR 17603-11:2020 (E)
2
References
The following documents are referenced in this text or provide additional information useful for the
reader.

EN Reference Reference in text Title
EN 16601-00-01 ECSS-S-ST-00-01 ECSS system – Glossary of terms
EN 16603-10 ECSS-E-ST-10 Space engineering – System engineering general
requirements
EN 16603-10-02 ECSS-E-ST-10-02 Space engineering – Verification
EN 16603-10-03 ECSS-E-ST-10-03 Space engineering – Testing
EN 16603-10-06 ECSS-E-ST-10-06 Space engineering – Technical requirements
specification
EN 16603-10-24 ECSS-E-ST-10-24 Space engineering – Interface management
EN 16603-11 ECSS-E-AS-11 Adoption notice of ISO 16290, Space systems –
Definition of the Technology Readiness Levels (TRLs)
and their criteria of assessment (1 October 2014)
TR 17603-10-02 ECSS-E-HB-10-02 Space engineering – Verification guidelines
EN 16603-40 ECSS-E-ST-40 Space engineering – Software
EN 16603-70 ECSS-E-ST-70 Space engineering – Ground systems and operations
EN 16601-10-10 ECSS-M-ST-10-01 Space project management – Organization and
conduct of reviews
EN 16601-60 ECSS-M-ST-60 Space project management – Cost and schedule
management
EN 16601-80 ECSS-M-ST-80 Space project management – Risk management
EN 16602-10 ECSS-Q-ST-10 Space product assurance – Product assurance
management
EN 16602-10-04 ECSS-Q-ST-10-04 Space product assurance – Critical-item control
EN 16602-20 ECSS-Q-ST-20 Space product assurance – Quality assurance
EN 16602-20-10 ECSS-Q-ST-20-10 Space product assurance – Off-the-shelf items
utilization in space systems
EN 16602-30 ECSS-Q-ST-30 Space product assurance – Dependability
EN 16602-40 ECSS-Q-ST-40 Space product assurance - Safety
EN 16602-60 ECSS-Q-ST-60 Space product assurance – Electrical, electronic and
electromechanical (EEE) components
8

---------------------- Page: 10 ----------------------
kSIST-TP FprCEN/CLC/TR 17603-11:2021
FprCEN/CLC/TR 17603-11:2020 (E)
EN Reference Reference in text Title
EN 16602-60-13 ECSS-Q-ST-60-13 Space product assurance – Commercial electrical,
electronic and electromechanical (EEE) components
EN 16602-70 ECSS-Q-ST-70 Space product assurance – Materials, mechanical parts
and processes
EN 16602-70-71 ECSS-Q-ST-70-71 Spaced product assurance – Materials, processes and
their data selection
EN 16602-80 ECSS-Q-ST-80 Space product assurance – Software product assurance
ISO 16290:2013 Space systems - Definition of the Technology
Readiness Levels (TRLs) and their criteria of
assessment
Mankins 95 reference TECHNOLOGY READINESS LEVELS, A White
(M95r) Paper, April 6, 1995, John C. Mankins Advanced
Concepts Office, Office of Space Access and
Technology NASA 1
https://www.hq.nasa.gov/office/codeq/trl/trl.pdf

9

---------------------- Page: 11 ----------------------
kSIST-TP FprCEN/CLC/TR 17603-11:2021
FprCEN/CLC/TR 17603-11:2020 (E)
3
Terms, definitions and abbreviated terms
3.1 Terms defined in other documents
a. For the purpose of this document, the terms and definitions from ECSS-E-AS-11 apply, in
particular for the following terms:
1. critical function of an element
NOTE The synonym of “critical function” is “critical function of an element”.
2. element
NOTE It is important to realize that the term element has a different meaning in
ECSS-E-AS-11 (that refer to ISO 16290) than in the ECSS Glossary of
terms (ECSS-S-ST-00-02). This guidelines use the term element as defined
in ISO 16290.
3. breadboard
4. laboratory environment
5. mature technology
6. operational environment
7. relevant environment
8. reproducible process
9. validation
b. For the purpose of this document the terms from ECSS-S-ST-00-01, except the terms listed in
3.1a apply, in particular for the following terms:
1. commissioning result review
2. component (context EEE)
NOTE For TRL 4 and TRL 5 the term “component” is understood as “part of a
larger whole”.
3. environment
4. ground segment
5. technology readiness level
c. For the purpose of this document the terms from ECSS-E-ST-70, except the terms listed in 3.1a.
and 3.1b apply, in particular for the following term:
1. Ground Segment QR (GSQR)
2. Operations QR (OQR)
3. Software Requirement Specification (SRS)
10

---------------------- Page: 12 ----------------------
kSIST-TP FprCEN/CLC/TR 17603-11:2021
FprCEN/CLC/TR 17603-11:2020 (E)
3.2 Terms specific to the present document
3.2.1 Research and Technology and Development (R&T&D)
activities to mature from research to technology to development as they are progressing from lower to
high TRL levels
3.3 Abbreviated terms and symbols
For the purpose of this document, the abbreviated terms from ECSS-S-ST-00-01 and the following
apply:
Abbreviation Meaning
acceptance review
AR
critical design review
CDR
commissioning readiness review
CRR
critical item list
CIL
development model
DM
displacement damage
DD
electrical, electronic and electromechanical
EEE
engineering model
EM
electromagnetic compatibility
EMC
engineering qualification model
EQM
equipment qualification status review
EQSR
European Space Components Coordination
ESCC
flight model
FM
In-orbit operations review
IOOR
International Standardization Organization
ISO
invitation to tender
ITT
Launch and early orbit phase
LEOP
Mankins 95 reference
M95r
mission definition review
MDR
National Aeronautics and Space Administration
NASA
new work item proposal
NWIP
Product Assurance
PA
printed circuit board
PCB
preliminary design review
PDR
protoflight model
PFM
proof of concept
POC
preliminary requirements review
PRR
qualification model
QM
11

---------------------- Page: 13 ----------------------
kSIST-TP FprCEN/CLC/TR 17603-11:2021
FprCEN/CLC/TR 17603-11:2020 (E)
Abbreviation Meaning
quality management system
QMS
qualification review
QR
reliability, availability, maintainability and safety
RAMS
radiofrequency
RF
Research and Technology and Development
R&T&D
single event effect
SEE
single event latch-up
SEL
structural model
SM
software problem report
SPR
software reuse file
SRF
structural thermal model
STM
total ionising dose
TID
thermal model
TM
terms of reference
ToR
technology plan
TP
technology readiness assessment
TRA
technology readiness level
TRL
technology readiness status list
TRSL
verification and validation
V&V
working group
WG
with respect to
w.r.t.

12

---------------------- Page: 14 ----------------------
kSIST-TP FprCEN/CLC/TR 17603-11:2021
FprCEN/CLC/TR 17603-11:2020 (E)
4
TRL history and evolution
4.1 History and evolution
The TRL methodology was originated at NASA in the 1970s in order to establish a method by which
NASA selected new technology amongst numerous candidates for their complex spaceflight
programmes. The scale progressed until 1995 with the definition of nine levels that became the
Mankins 95 reference (M95r) [see clause2]. From that moment, the principle of a maturity scale was
adopted by many companies and government agencies around the world. However, although they
were somewhat similar, different definitions or interpretation of the M95r were used. ECSS decided,
in 2008, to first make a harmonization at European level and then to propose to ISO a global
harmonization in 2009. This then resulted in an ISO New Work Item Proposal (NWIP) “Definition of
the Technology Readiness Levels (TRLs) and their criteria of assessment”.
The ISO standard 16290 was published in 2013 and as a result, TRL are now globally harmonized.
ECSS actively contributed to this ISO standard by providing members to the ISO WG. The ISO
standard concerns the definition and the criteria of assessment, however the procedure for the TRL
assessment or the way to use them within a project’s framework was not the purpose of the standard.
The standard is applicable primarily to space system hardware, although the definitions are used in a
wider domain in many cases.
It is important to recognise that the ISO standard introduces some modifications with regards to the
M95r previous interpretation in ECSS documents.
4.2 Differences between M95r and ISO 16290 standard
as seen by ECSS (European interpretation)
Below is given a summary of the differences between M95r and ISO 16290 standard, supported by
Figure 4-1:
 ISO levels 1, 2, 3 and 4 definitions are equivalent to M95r (see clause 2) .
 ISO level 5 is a new intermediate level defined for when breadboards at sub-scales are used (the
breadboards used to demonstrate the critical function in a relevant environment are not full
scale or full function representations of the flight equipment).
 ISO level 6 is equivalent to M95r level 5.
 ISO level 7 is equivalent to M95r level 6.
 ISO does not recognize M95r level 7 which was “System prototype demonstration in space
environment”.
 ISO levels 8 and 9 are equivalent to M95r definitions respectively defining “flight qualified”
(qualified for flight) and “flight proven” for the actual systems.
Differences between M95r and ISO are summed up in Figure 4-1.
13

---------------------- Page: 15 ----------------------
kSIST-TP FprCEN/CLC/TR 17603-11:2021
FprCEN/CLC/TR 17603-11:2020 (E)
Mankins 95 reference ISO 16290 standard
TRL 1 Basic principles observed and reported Basic principles observed and reported
Equivalent
TRL 2 Technology concept and/or application formulated Technology concept and/or application formulated
Equivalent
TRL 3 Analytical and experimental critical function and/or Analytical and experimental critical function and/or
Equivalent
characteristic proof-ofconcept characteristic proof-ofconcept
TRL 4 Component and/or breadboard validation in Component and/or breadboard functional verification
Equivalent
laboratory environment in laboratory environment
TRL 5 Component and/or breadboard validation in relevant Component and/or breadboard critical function
 Split
environment verification in a relevant environment
TRL 6 System/subsystem model or prototype demonstration Model demonstrating the critical functions of the
 Shifted
in a relevant environment (ground or space) element in a relevant environment
TRL 7 System prototype demonstration in a space Model demonstrating the element performance for the
 Removed
environment operational environment
TRL 8 Actual system completed and “flight qualified” Actual system completed and accepted for flight
Equivalent
through test and demonstration (ground or space) (“flight qualified”)
TRL 9 Actual system “flight proven” through successful Actual system “flight proven” through successful
Equivalent
mission operations mission operations

Figure 4-1: Illustration of differences between M95r (European interpretation) and
ECSS-E-AS-11
The M95r scale is now obsolete and for the remainder of this handbook, the term TRL is referring to
ECSS-E-AS-11 definition.
4.3 TRL implementation in ECSS system
TRL are implemented in ECSS system following four ways:
1. adoption of the ISO 16290 with an Adoption Notice (AN ref ECSS-E-AS-11),
2. introduction in the ECSS standards of the reference to the AN when TRL are used,
3. introduction in the ECSS standards of the requirements to manage the use of TRL,
4. provision of guidelines in this handbook.
The adoption notice ECSS-E-AS-11 was necessary to provide a concise method of introducing the ISO
standard in ECSS system. The AN was needed to make normative the TRL following ECSS editorial
rules, to align the terms definition and to make reference when necessary to ECSS type of reviews.
This handbook provides guidelines on the way to assess a product, to use the TRL assessment
outcome in the product and project development framework, and to introduce some refinements for
specific disciplines or products.
4.4 TRL and assessment basic principles
Technology readiness assessment (TRA, see clause 5) allows for the assignment of a measure of the
maturity of a technology. It is important to make clear that undertaking a TRA is not a method to
develop technologies. The way to develop, to test, to qualify or to verify the development cycle of
products, or the model philosophy defined by projects, are not the object of TRL but the purpose of
others discipline-specific ECSS standards and handbooks.
The measure provided by TRL assessment is valid for a given element, at a given point in time, and a
given defined environment. It changes if the conditions (such as operational environment) that
14

---------------------- Page: 16 ----------------------
kSIST-TP FprCEN/CLC/TR 17603-11:2021
FprCEN/CLC/TR 17603-11:2020 (E)
prevailed at the time of the assessment are no longer valid. Such a situation leads to TRL reassessment
and re-grading, which can occur in particular when the re-build or re-use of an element is envisioned
with variation in the design, development process, targeted environment or operations.
During Research and Development, or Research and Technology (R&T&D) activities, TRL can be used
by the specialists developing the technologies to present their development plans (e.g. technology
roadmaps) and to communicate with non-specialists or project managers, the costs or risks involved in
taking particular technology choices with different TRLs.
In the framework of projects, TRL is used during preliminary phases (0, A, B) as a tool supporting the
decision whether or not to use or integrate specific technology in a space mission, and allowing such
decision to be taken with sufficient knowledge of any risk relating to the degree of maturity.
Generally R&T&D programs push (“research push”) the technologies maturity as far as the
intermediate TRLs. Projects then pull some technologies and develop these to the higher levels of
maturity.
The intermediate levels of maturity (typically TRLs 4
...