Space engineering - Mechanisms

This Standard specifies the requirements applicable to the concept definition, design, analysis, development, production, test verification and in­orbit operation of space mechanisms on spacecraft and payloads in order to meet the mission performance requirements.
This version of the standard has not been produced with the objective to cover also the requirements for mechanisms on launchers. Applicability of the requirements contained in this current version of the standard to launcher mechanisms is a decision left to the individual launcher project.
Requirements in this Standard are defined in terms of what shall be accomplished, rather than in terms of how to organise and perform the necessary work. This allows existing organizational structures and methods to be applied where they are effective, and for the structures and methods to evolve as necessary without rewriting the standards. Complementary non ECSS handbooks and guidelines exist to support mechanism design.
This standard may be tailored for the specific characteristic and constrains of a space project in conformance with ECSS-S-ST-00.

Raumfahrttechnik - Mechanik/Mechanismen

Ingénierie spatiale - Mécanismes

Vesoljska tehnika - Mehanizmi

Ta standard določa zahteve, ki se uporabljajo za definicijo zasnove, načrtovanje, analizo, razvoj, proizvodnjo, preverjanje s preskusi in delovanje vesoljskih mehanizmov na vesoljskih plovilih in tovorih v orbiti, da se izpolnijo zahteve glede ciljev misije.
Ta različica standarda ni bila pripravljena z namenom, da zajema tudi zahteve za mehanizme na lansirnikih. Uporabnost zahtev iz te trenutne različice standarda za mehanizme lansirnikov je odločitev posameznega projekta lansirnika.
Zahteve v tem standardu so opredeljene v smislu, kaj je treba doseči in ne kako organizirati in opraviti potrebno delo. To omogoča uporabo organizacijskih struktur in metod tam, kjer so učinkovite, in potreben razvoj struktur in metod brez spreminjanja standardov. Za podporo načrtovanju mehanizmov obstajajo dodatni priročniki in navodila, ki jih ni pripravila organizacija ECSS.
Ta standard se lahko prilagodi posameznim lastnostim in omejitvam vesoljskega projekta v skladu s standardom ECSS-S-ST-00.

General Information

Status
Published
Public Enquiry End Date
05-Sep-2018
Publication Date
13-May-2019
Technical Committee
Current Stage
6060 - National Implementation/Publication (Adopted Project)
Start Date
25-Apr-2019
Due Date
30-Jun-2019
Completion Date
14-May-2019

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SLOVENSKI STANDARD
SIST EN 16603-33-01:2019
01-julij-2019
Vesoljska tehnika - Mehanizmi
Space engineering - Mechanisms
Raumfahrttechnik - Mechanik/Mechanismen
Ingénierie spatiale - Mécanismes
Ta slovenski standard je istoveten z: EN 16603-33-01:2019
ICS:
49.140 Vesoljski sistemi in operacije Space systems and
operations
SIST EN 16603-33-01:2019 en,fr,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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SIST EN 16603-33-01:2019

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SIST EN 16603-33-01:2019


EUROPEAN STANDARD EN 16603-33-01

NORME EUROPÉENNE

EUROPÄISCHE NORM
April 2019
ICS 49.140

English version

Space engineering - Mechanisms
Ingénierie spatiale - Mécanismes Raumfahrttechnik - Mechanik/Mechanismen
This European Standard was approved by CEN on 7 October 2018.

CEN and CENELEC members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for
giving this European Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical
references concerning such national standards may be obtained on application to the CEN-CENELEC Management Centre or to
any CEN and CENELEC member.

This European Standard exists in three official versions (English, French, German). A version in any other language made by
translation under the responsibility of a CEN and CENELEC member into its own language and notified to the CEN-CENELEC
Management Centre has the same status as the official versions.

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
























CEN-CENELEC Management Centre:
Rue de la Science 23, B-1040 Brussels
© 2019 CEN/CENELEC All rights of exploitation in any form and by any means Ref. No. EN 16603-33-01:2019 E
reserved worldwide for CEN national Members and for
CENELEC Members.

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SIST EN 16603-33-01:2019
EN 16603-33-01:2019 (E)
Table of contents
European Foreword . 5
Introduction . 6
1 Scope . 7
2 Normative references . 8
3 Terms, definitions and abbreviated terms . 10
3.1 Terms from other standards . 10
3.2 Terms specific to the present standard . 10
3.3 Abbreviated terms. 13
3.4 Nomenclature . 14
4 Requirements . 15
4.1 Overview . 15
4.2 General requirements . 15
4.2.1 Overview . 15
4.2.2 Mission specific requirements . 15
4.2.3 Units . 16
4.2.4 Product characteristics . 16
4.2.5 Reliability and redundancy . 17
4.2.6 Flushing and purging . 18
4.3 Mission and environments . 18
4.4 Functional . 19
4.4.1 System performance . 19
4.4.2 Mechanism function . 19
4.5 Constraints . 19
4.5.1 Overview . 19
4.5.2 Materials . 19
4.5.3 Operational constraints . 21
4.6 Interfaces . 21
4.6.1 Overview . 21
2

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EN 16603-33-01:2019 (E)
4.6.2 Thermo-mechanical interfaces . 21
4.7 Design requirements . 21
4.7.1 Overview . 21
4.7.2 General design . 22
4.7.3 Tribology . 22
4.7.4 Thermal control . 25
4.7.5 Mechanical design and sizing . 26
4.7.6 Pyrotechnics . 37
4.7.7 Electrical and electronic . 37
4.7.8 Open-loop and closed-loop control system for mechanisms . 39
4.8 Verification . 41
4.8.1 General . 41
4.8.2 Verification by analysis . 41
4.8.3 Verification by test . 46
4.9 Production and manufacturing . 54
4.9.1 Manufacturing process . 54
4.9.2 Manufacturing drawings . 54
4.9.3 Assembly . 55
4.10 Deliverables . 55
Annex A (normative) Specific mechanism specification (SMS) - DRD . 56
Annex B (normative) Mechanism design description (MDD) - DRD . 60
Annex C (normative) Mechanism analytical verification (MAV) - DRD . 62
Annex D (normative) Mechanism user manual (MUM) - DRD . 64
Annex E (informative) Documentation technical items . 68
Annex F (normative) Safety critical mechanisms verification plan (MSVP) -
DRD . 69
Annex G (normative) Safety critical mechanisms verification report (MSVR)
- DRD . 72
Bibliography . 74

Tables
Table 4-1:<> . 24
Table 4-2: Minimum uncertainty factors for actuation function . 29
Table 4-3:Minimum uncertainty factors for holding function . 32
Table 4-4: Life test duration factors . 50
3

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EN 16603-33-01:2019 (E)
Table 4-5: Examples of lifetime to be demonstrated by test . 51
Table 4-6: Example of lifetime to be demonstrated by test for safety critical mechanisms
having critical hazard potential . 52
Table 4-7: Example of lifetime to be demonstrated by test for safety critical mechanisms
having catastrophic hazard potential . 52

Table E-1 : Documentation technical items . 68


4

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SIST EN 16603-33-01:2019
EN 16603-33-01:2019 (E)
European Foreword
This document (EN 16603-33-01:2019) has been prepared by Technical Committee
CEN-CENELEC/TC 5 “Space”, the secretariat of which is held by DIN.
This standard (EN 16603-33-01:2019) originates from ECSS-E-ST-33-01C Rev.1.
This European Standard shall be given the status of a national standard, either by
publication of an identical text or by endorsement, at the latest by October 2019,
and conflicting national standards shall be withdrawn at the latest by October
2019.
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 standardization request 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 EN covering the same scope but with a wider
domain of applicability (e.g. : aerospace).
According to the CEN-CENELEC Internal Regulations, the national standards
organizations of the following countries are bound to implement this European
Standard: Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic,
Denmark, Estonia, Finland, Former Yugoslav Republic of Macedonia, France,
Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania,
Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Serbia,
Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and the United
Kingdom.

5

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SIST EN 16603-33-01:2019
EN 16603-33-01:2019 (E)
Introduction
This document has been established to provide mechanism engineering teams
with a set of requirements, design rules and guidelines based on the state of the
art knowledge and experience in the field of space mechanisms.
The use of this document helps mechanisms developers to establish generic
mechanisms designs and to derive application specific requirements.
The main objectives are to achieve reliable operation of space mechanisms in
orbit and to prevent anomalies during the development phase influencing
schedule and cost efficiency of space programmes.
6

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SIST EN 16603-33-01:2019
EN 16603-33-01:2019 (E)
1
Scope
This Standard specifies the requirements applicable to the concept definition,
design, analysis, development, production, test verification and in­orbit
operation of space mechanisms on spacecraft and payloads in order to meet the
mission performance requirements.
This version of the standard has not been produced with the objective to cover
also the requirements for mechanisms on launchers. Applicability of the
requirements contained in this current version of the standard to launcher
mechanisms is a decision left to the individual launcher project.
Requirements in this Standard are defined in terms of what shall be
accomplished, rather than in terms of how to organise and perform the necessary
work. This allows existing organizational structures and methods to be applied
where they are effective, and for the structures and methods to evolve as
necessary without rewriting the standards. Complementary non-ECSS
handbooks and guidelines exist to support mechanism design.
This standard may be tailored for the specific characteristic and constrains of a
space project in conformance with ECSS-S-ST-00.
7

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SIST EN 16603-33-01:2019
EN 16603-33-01:2019 (E)
2
Normative references
The following normative documents contain provisions which, through reference
in this text, constitute provisions of this ECSS standard. For dated references,
subsequent amendments to or revisions of any of these publications do not apply.
However, parties to agreements based on this ECSS Standard are encouraged to
investigate the possibility of applying the most recent editions of the normative
documents indicated below. For undated references the latest edition of the
publication referred to applies.

EN reference Reference in text Title
EN 16601-00-01 ECSS-S-ST-00-01 ECSS system — Glossary of terms
EN 16603-10-02 ECSS-E-ST-10-02 Space engineering – Verification
EN 16603-20 ECSS-E-ST-20 Space engineering – Electrical and electronic
EN 16603-06 ECSS-E-ST-20-06 Space engineering – Spacecraft charging
EN 16603-07 ECSS-E-ST-20-07 Space engineering – Electromagnetic compatibility
EN 16603-31 ECSS-E-ST-31 Space engineering – Thermal control general
requirements
EN 16603-32 ECSS-E-ST-32 Space engineering – Structural
EN 16603-32-01 ECSS-E-ST-32-01 Space engineering – Fracture control
EN 16603-32-10 ECSS-E-ST-32-10 Space engineering – Structural factors of safety for
spaceflight hardware
EN 16603-33-11 ECSS-E-ST-33-11 Space engineering – Explosive systems and devices
EN 16602-30 ECSS-Q-ST-30 Space product assurance - Dependability
EN 16602-40 ECSS-Q-ST-40 Space product assurance – Safety
EN 16602-70 ECSS-Q-ST-70 Space product assurance – material, mechanical part
and process
EN 16602-70-36 ECSS-Q-ST-70-36 Space product assurance – Material selection for
controlling stress corrosion cracking
EN 16602-70-37 ECSS-Q-ST-70-37 Space product assurance – Determination of the
susceptibility of metals to stress corrosion cracking
EN 16602-70-71 ECSS-Q-ST-70-71 Space product assurance – Data for selection of space
materials and processes
ISO 76 (2006) Rolling bearings – Static load rating
ISO 128 (1996) Technical drawings
8

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EN 16603-33-01:2019 (E)
EN reference Reference in text Title
ISO 677 (1976) Straight bevel gears for general engineering and for
heavy engineering – Basic rack
ISO 678 (1976) Straight bevel gears for general engineering and for
heavy engineering – Modules and diametral pitches
ISO 6336-1 (2006) Calculation of the load capacity of spur and helical
gears — Part 1: Basic principles, introduction and
general influence factors
ISO 6336-2 (2006) Calculation of the load capacity of spur and helical
gears — Part 2: Calculation of surface durability
(pitting)
ISO 6336-3 (2006) Calculation of the load capacity of spur and helical
gears — Part 3: Calculation of tooth bending strength

9

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SIST EN 16603-33-01:2019
EN 16603-33-01:2019 (E)
3
Terms, definitions and abbreviated terms
3.1 Terms from other standards
a. For the purpose of this Standard, the term and definition from ECSS-S-ST-
00-01 apply, and in particular the following:
1. cleanliness
2. component
3. interface
4. product
b. For the purpose of this Standard, the term and definition from ECSS-S-ST-
32-10 apply, and in particular the following:
1. fail-safe
2. model factor (KM)
3. project factor (KP)
3.2 Terms specific to the present standard
3.2.1 actuator
component that performs the moving function of a mechanism
NOTE 1 An actuator can be either an electric motor, or
any other mechanical (e.g. spring) or electric
component or part providing the torque or force
for the motion of the mechanism.
NOTE 2 This term is defined in the present standard with
a different meaning than in ECSS-S-ST-00-01. The
term with the meaning defined herein is
applicable only to the present standard.
3.2.2 control system
system (open or closed loop) which controls the relative motion of the
mechanism
10

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SIST EN 16603-33-01:2019
EN 16603-33-01:2019 (E)
3.2.3 deliverable output torque (T )
L
torque at the mechanism or actuator output
NOTE 1 The deliverable output torque or force can be
specified by the customer for an undefined
purpose and not affect the actual performance of
the mechanism.
NOTE 2 For example: A theoretical torque or force of a
robotic mechanism (service tool) for which no
specific function except torque or force provision
can be specified at an early stage in the project
development.
3.2.4 deliverable output force (F )
L
force at the mechanism or actuator output
3.2.5 elementary function
lowest level function
NOTE For example: One degree of freedom (rotation
and translation), torque or force generation,
sensing.
3.2.6 inertial resistance force (F )
D
force to accelerate the mass
3.2.7 inertial resistance torque(T )
D
torque to accelerate the inertia
3.2.8 fastener
item used to provide attachment of two or more separate parts, components or
assemblies
NOTE For example: Fasteners have the function of
locking the parts together and providing the
structural load path between the parts or, if used
as a securing part, to ensure proper locating of
the parts to be secured.
3.2.9 flushing or purging
control of the mechanism environment by enclosing the mechanism in specific
gaseous or fluid media which are surrounding, passing over or through the
mechanism
3.2.10 latching or locking
intentional constraining of one or more previously unconstrained degrees of
freedom which cannot be released without specific action
11

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SIST EN 16603-33-01:2019
EN 16603-33-01:2019 (E)
3.2.11 lubrication
use of specific material surface properties or an applied material between two
contacting or moving surfaces in order to reduce friction, wear or adhesion
3.2.12 mechanism
assembly of parts that are linked together to enable a relative motion
3.2.13 off-loading
complete or partial unloading of a part or assembly from an initial pre-load
NOTE Off-loading is usually employed so as not to
expose a mechanisms part or assembly to launch
loads or other induced loads.
3.2.14 phase margin
indicator for the stability of dynamic control systems
3.2.15 positively locked
form-locked into a defined position from which release can only be obtained by
application of a specific actuation force
3.2.16 positive indication of status
direct monitoring of the state of the primary function at the output level of the
mechanism
3.2.17 primary function
high level function
NOTE For example: To hold, to release, to deploy, to
track, and to point.
3.2.18 safety critical mechanism
mechanical product having a critical or catastrophic hazard potential
3.2.19 threaded fastener
fastener with a threaded portion
NOTE For example: Screws, bolts and studs.
3.2.20 tribology
discipline that deals with the design, friction, wear and lubrication of interacting
surfaces in relative motion to each other
3.2.21 venting
compensation of the internal mechanism pressure environment with its
surrounding pressure environment
NOTE For example: Use of dedicated venting holes or
passages
12

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SIST EN 16603-33-01:2019
EN 16603-33-01:2019 (E)
3.3 Abbreviated terms
For the purpose of this Standard, the abbreviated terms from ECSS-S-ST-00-01
and the following apply:

Abbreviation Meaning
analogue to digital
A/D
alternating current
AC
centre of gravity
COG
collected volatile condensable material
CVCM
digital to analogue
D/A
direct current
DC
design for minimum risk
DFMR
design limits loads
DLL
electromagnetic compatibility
EMC
electrostatic discharge
ESD
actuation force
F
F inertial resistance force
D
F deliverable output force
L
failure mode effects and criticality analysis
FMECA
F
min minimum actuator force required
factor of safety
FOS
F friction torque or force
R
ground support equipment
GSE
H
A harness and other torque or force resistances
H adhesion torque or force
D
hardness Vickers
HV
H hysteresis torque or force
Y
inertia resistance (linear or angular)
I
Interface
I/F
low Earth orbit
LEO
mass
M
mechanism analytical verification
MAV
mechanism design description
MDD
mechanism user manual
MUM
multi­layer insulation
MLI
moment of inertia
MOI
margin of safety
MOS
13

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SIST EN 16603-33-01:2019
EN 16603-33-01:2019 (E)
Abbreviation Meaning
strength safety margin
MS
safety critical mechanisms verification plan
MSVP
safety critical mechanisms verification report
MSVR
not applicable
n.a.
specific mechanism specification
SMS
recovered mass loss
RML
spring force
S
international system of units
SI
spacecraft
S/C
specific mechanism specification
SMS
actuation torque
T
T inertial resistance torque
D
T
L deliverable output torque
T minimum actuator torque required
min
total mass loss
TML
ultraviolet
UV
verification control document
VCD
3.4 Nomenclature
The following nomenclature applies throughout this document:
a. The word “shall” is used in this Standard to express requirements. All the
requirements are expressed with the word “shall”.
b. The word “should” is used in this Standard to express recommendations.
All the recommendations are expressed with the word “should”.
NOTE It is expected that, during tailoring,
recommendations in this document are either
converted into requirements or tailored out.
c. The words “may” and “need not” are used in this Standard to express
positive and negative permissions, respectively. All the positive
permissions are expressed with the word “may”. All the negative
permissions are expressed with the words “need not”.
d. The word “can” is used in this Standard to express capabilities or
possibilities, and therefore, if not accompanied by one of the previous
words, it implies descriptive text.
NOTE In ECSS “may” and “can” have completely
different meanings: “may” is normative
(permission), and “can” is descriptive.
e. The present and past tenses are used in this Standard to express statements
of fact, and therefore they imply descriptive text.
14

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EN 16603-33-01:2019 (E)
4
Requirements
4.1 Overview
This Standard addresses the requirements related to the generic aspects of the
engineering steps for the various engineering disciplines involved in the
achievement of the specified space mechanism performance.
The following requirements are identified considering interfaces and interactions
of mechanisms with those disciplines: thermal control, structures, functional
operations, materials and parts, pyrotechnics, propulsion, electrical and
electronics, and servo­control interactions. Where interactions with other
European space regulation are identified, reference is made to the related
regulation.
4.2 General requirements
4.2.1 Overview
Requirements of clause 4.2 cover the interaction of mechanisms engineering with
project management, processes, parts and components, product assurance, and
the related requirements affecting the conceptual definition, design, sizing,
analysis, development, and hardware production of mechanisms.
In view of the criticality of space mechanisms, which are often potential mission
critical single point failures, particular attention is placed upon the reliability and
redundancy of space mechanisms (see clause 4.2.5).
4.2.2 Mission specific requirements
a. A dedicated specific mechanism specification (SMS) shall be established in
conformance with Annex A for each individual mechanism in a project,
and agreed by the customer.
NOTE The SMS specification identifies all specific
requirements for a specific mechanism in a
project, that are not covered by the present
standard.
15

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EN 16603-33-01:2019 (E)
4.2.3 Units
a. SI-units and associated symbols system shall be used.
4.2.4 Product characteristics
4.2.4.1 Marking and labelling
4.2.4.1.1 Specific identification
a. The identification of delivered pieces of hardware, parts, components,
sub­assemblies and assemblies shall carry at least the equipment title.
NOTE 1 For the identification of pieces of hardware,
parts, components, sub­assemblies, and
assemblies of the mechanism, see clause 5.3.1.5 of
ECSS-M-ST-40.
NOTE 2 The identification can be removable.
NOTE 3 The identification number and the equipment
title can be defined by the contracting authority.
4.2.4.1.2 Marking
a. Marking shall be applied on non-functional surfaces.
b. Bearings shall not be marked by the use of vibro­etch marks on the lateral
faces of the bearing races.
NOTE Etched marks on the lateral faces of the bearing
races affect the mounting tolerances of the
bearing in the housing and the bearing’s
tribological performance characteristics.
4.2.4.2 Parts and components
a. Existing parts and components used in mechanisms shall have been
previously qualified for the intended application according to a
qualification procedure approved by the customer.
NOTE Existing parts and components relate to parts
and components that were not specifically
developed for this specific application and cover
commercially available and off-the-shelf
hardware.
b. Existing parts and components used in mechanisms should have been
previously qualified at part or component level.
c. Flight proven parts and components should be used.
NOTE For the selection of not-flight proven parts and
components, see ECSS-Q-ST-60 for EEE
components and ECSS-Q-ST-70 for materials and
parts.
16

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SIST EN 16603-33-01:2019
EN 16603-33-01:2019 (E)
4.2.4.3 Interchangeability
a. All items having the same identification number shall be functionally and
dimensionally interchangeable.
4.2.4.4 Maintainability
a. The mechanism should be designed to be maintenance free during storage
and ground life.
b. If the design is not maintenance free, the maintenance requirements shall
be documented in the SMS, justified, agreed by the customer.
c. If ground maintenance during storage or ground operation is not avoided,
the maintenance procedures shall be provided.
4.2.5 Reliability and redundancy
4.2.5.1 Reliability
a. For all mechanisms, which are critical to mission success, conformance to
the specified reliability figure shall be demonstrated according to the
following methods:
1. electronic components: by parts count as a minimum or other
methods approved by the customer;
2. mechanical parts: by stress analysis or other methods approved by
the customer;
3. mechanical limited­life: by life test approved by the customer.
b. For non­critical mechanisms, conformance to the reliability figure shall be
demonstrated by simplified methods or other methods accepted by the
customer.
NOTE 1 The methods to achieve by design, derive by
analysis, and demonstrate by test the specified
reliability figures are presented in ECSS-Q-ST-30.
NOTE 2 An example of a simplified method is parts
count.
c. Failure of one part or element shall not result in consequential damage to
the equipment or other spacecraft components.
d. For structural reliability aspects ECSS-E-ST-32 shall apply.
e. For safety critical mechanisms in a crewed space mission where structural
failure can cause a catastrophic hazardous event, fasteners and load
carrying paths within mechanisms shall be designed in conformance with
fracture control requirements from ECSS-E-ST
...

SLOVENSKI STANDARD
kSIST FprEN 16603-33-01:2018
01-september-2018
Vesoljska tehnika - Mehanizmi
Space engineering - Mechanisms
Raumfahrttechnik - Mechanik/Mechanismen
Ingénierie spatiale - Mécanismes
Ta slovenski standard je istoveten z: FprEN 16603-33-01
ICS:
49.140 Vesoljski sistemi in operacije Space systems and
operations
kSIST FprEN 16603-33-01:2018 en,fr,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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kSIST FprEN 16603-33-01:2018

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kSIST FprEN 16603-33-01:2018


EUROPEAN STANDARD
FINAL DRAFT
FprEN 16603-33-01
NORME EUROPÉENNE

EUROPÄISCHE NORM

November 2016
ICS 49.140

English version

Space engineering - Mechanisms
Ing?ierie spatiale - M?anismes Raumfahrttechnik - Mechanik/Mechanismen
This draft European Standard is submitted to CEN members for unique acceptance procedure. It has been drawn up by the
Technical Committee CEN/CLC/TC 5.

If this draft becomes a European Standard, CEN and CENELEC members are bound to comply with the CEN/CENELEC Internal
Regulations which stipulate the conditions for giving this European Standard the status of a national standard without any
alteration.

This draft European Standard was established by CEN and CENELEC in three official versions (English, French, German). A
version in any other language made by translation under the responsibility of a CEN and CENELEC member into its own
language and notified to the CEN-CENELEC Management Centre has the same status as the official versions.

CEN and CENELEC members are the national standards bodies and national electrotechnical committees of Austria, Belgium,
Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, Former Yugoslav Republic of Macedonia, France, Germany,
Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania,
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 European Standard. It is distributed for review and comments. It is subject to change without
notice and shall not be referred to as a European Standard.

















CEN-CENELEC Management Centre:
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© 2016 CEN/CENELEC All rights of exploitation in any form and by any means Ref. No. FprEN 16603-33-01:2016 E
reserved worldwide for CEN national Members and for
CENELEC Members.

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Table of contents
Foreword . 4
Introduction . 5
1 Scope . 6
2 Normative references . 7
3 Terms, definitions and abbreviated terms . 9
3.1 Terms from other standards . 9
3.2 Terms specific to the present standard . 9
3.3 Abbreviated terms. 11
4 Requirements . 14
4.1 Overview . 14
4.2 General requirements . 14
4.2.1 Overview . 14
4.2.2 Mission specific requirements . 14
4.2.3 Units . 15
4.2.4 Product characteristics . 15
4.2.5 Reliability and redundancy . 16
4.2.6 Flushing and purging . 17
4.3 Mission and environments . 18
4.4 Functional . 18
4.4.1 System performance . 18
4.4.2 Mechanism function . 18
4.5 Constraints . 18
4.5.1 Overview . 18
4.5.2 Materials . 19
4.5.3 Operational constraints . 20
4.6 Interfaces . 21
4.6.1 Overview . 21
4.6.2 Thermo-mechanical interfaces . 21
4.7 Design requirements . 21
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4.7.1 Overview . 21
4.7.2 General design . 21
4.7.3 Tribology . 22
4.7.4 Thermal control . 25
4.7.5 Mechanical design and sizing . 26
4.7.6 Pyrotechnics . 37
4.7.7 Electrical and electronic . 37
4.7.8 Open-loop and closed-loop control system for mechanisms . 39
4.8 Verification . 41
4.8.1 General . 41
4.8.2 Verification by analysis . 41
4.8.3 Verification by test . 46
4.9 Production and manufacturing . 53
4.9.1 Manufacturing process . 53
4.9.2 Manufacturing drawings . 53
4.9.3 Assembly . 53
4.10 Deliverables . 53
Annex A (normative) Specific mechanism specification (SMS) - DRD . 55
Annex B (normative) Mechanism design description (MDD) - DRD . 59
Annex C (normative) Mechanism analytical verification (MAV) - DRD . 61
Annex D (normative) Mechanism user manual (MUM) - DRD . 63
Annex E (informative) Documentation technical items . 67
Annex F (normative) Safety critical mechanisms verification plan (MSVP) -
DRD . 68
Annex G (normative) Safety critical mechanisms verification report (MSVR)
- DRD . 71
Bibliography . 73

Tables
Table 4-1: Outgassing limits . 23
Table 4-2: Minimum uncertainty factors . 28
Table 4-3:Minimum uncertainty factors . 32
Table 4-4: Life test duration factors . 50
Table 4-5: Examples of lifetime to be demonstrated by test . 50
Table E-1 : Documentation technical items . 67
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Foreword
This document (FprEN 16603-33-01:2016) has been prepared by Technical Committee CEN/CLC/TC 5
“Space”, the secretariat of which is held by DIN (Germany).
This document (FprEN 16603-33-01:2016) originates from ECSS-E-ST-33-01C Rev.1 DIR1.
This document is currently submitted to the Unique Acceptance Procedure.
This document has been developed to cover specifically space systems and will the-refore have
precedence over any EN covering the same scope but with a wider do-main of applicability (e.g.:
aerospace).

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Introduction
This document has been established to provide mechanism engineering teams
with a set of requirements, design rules and guidelines based on the state of the
art knowledge and experience in the field of space mechanisms.
The use of this document helps mechanisms developers to establish generic
mechanisms designs and to derive application specific requirements.
The main objectives are to achieve reliable operation of space mechanisms in
orbit and to prevent anomalies during the development phase influencing
schedule and cost efficiency of space programmes.
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1
Scope
This Standard specifies the requirements applicable to the concept definition,
design, analysis, development, production, test verification and in-orbit
operation of space mechanisms on spacecraft and payloads in order to meet the
mission performance requirements.
This version of the standard has not been produced with the objective to cover
also the requirements for mechanisms on launchers. Applicability of the
requirements contained in this current version of the standard to launcher
mechanisms is a decision left to the individual launcher project.
Requirements in this Standard are defined in terms of what shall be
accomplished, rather than in terms of how to organise and perform the necessary
work. This allows existing organizational structures and methods to be applied
where they are effective, and for the structures and methods to evolve as
necessary without rewriting the standards. Complementary non ECSS
handbooks and guidelines exist to support mechanism design.
This standard may be tailored for the specific characteristic and constrains of a
space project in conformance with ECSS-S-ST-00.
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2
Normative references
The following normative documents contain provisions which, through reference
in this text, constitute provisions of this ECSS standard. For dated references,
subsequent amendments to or revisions of any of these publications do not apply.
However, parties to agreements based on this ECSS Standard are encouraged to
investigate the possibility of applying the most recent editions of the normative
documents indicated below. For undated references the latest edition of the
publication referred to applies.

EN reference Reference in text Title
EN 16601-00-01 ECSS-S-ST-00-01 ECSS system — Glossary of terms
EN 16603-10-02 ECSS-E-ST-10-02 Space engineering – Verification
EN 16603-20 ECSS-E-ST-20 Space engineering – Electrical and electronic
EN 16603-20-06 ECSS-E-ST-20-06 Space engineering – Spacecraft charging
EN 16603-20-07 ECSS-E-ST-20-07 Space engineering – Electromagnetic compatibility
EN 16603-31 ECSS-E-ST-31 Space engineering – Thermal control general
requirements
EN 16603-32 ECSS-E-ST-32 Space engineering – Structural
EN 16603-32-01 ECSS-E-ST-32-01 Space engineering – Fracture control
EN 16603-32-10 ECSS-E-ST-32-10 Space engineering – Structural factors of safety for
spaceflight hardware
EN 16603-33-11 ECSS-E-ST-33-11 Space engineering – Explosive systems and devices
EN 16602-30 ECSS-Q-ST-30 Space product assurance - Dependability
EN 16602-40 ECSS-Q-ST-40 Space product assurance – Safety
EN 16602-70 ECSS-Q-ST-70 Space product assurance – material, mechanical
part and process
EN 16602-70-36 ECSS-Q-ST-70-36 Space product assurance – Material selection for
controlling stress corrosion cracking
EN 16602-70-37 ECSS-Q-ST-70-37 Space product assurance – Determination of the
susceptibility of metals to stress corrosion cracking
EN 16602-70-71 ECSS-Q-ST-70-71 Space product assurance – Data for selection of
space materials and processes
ISO 76 (2006) Rolling bearings – Static load rating
ISO 128 (1996) Technical drawings
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EN reference Reference in text Title
ISO 677 (1976) Straight bevel gears for general engineering and for
heavy engineering – Basic rack
ISO 678 (1976) Straight bevel gears for general engineering and for
heavy engineering – Modules and diametral pitches
ISO 6336-1 (2006) Calculation of the load capacity of spur and helical
gears — Part 1: Basic principles, introduction and
general influence factors
ISO 6336-2 (2006) Calculation of the load capacity of spur and helical
gears — Part 2: Calculation of surface durability
(pitting)
ISO 6336-3 (2006) Calculation of the load capacity of spur and helical
gears — Part 3: Calculation of tooth bending
strength

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3
Terms, definitions and abbreviated terms
3.1 Terms from other standards
a. For the purpose of this Standard, the term and definition from ECSS-S-ST-
00-01 apply, and in particular the following:
1. cleanliness
2. component
3. interface
4. product
3.2 Terms specific to the present standard
3.2.1 actuator
component that performs the moving function of a mechanism
NOTE 1 An actuator can be either an electric motor, or
any other mechanical (e.g. spring) or electric
component or part providing the torque or force
for the motion of the mechanism.
NOTE 2 This term is defined in the present standard with
a different meaning than in ECSS-S-ST-00-01. The
term with the meaning defined herein is
applicable only to the present standard.
3.2.2 control system
system (open or closed loop) which controls the relative motion of the
mechanism
3.2.3 deliverable output torque (T )
L
torque at the mechanism or actuator output
NOTE 1 The deliverable output torque or force can be
specified by the customer for an undefined
purpose and not affect the actual performance of
the mechanism.
NOTE 2 For example: A theoretical torque or force of a
robotic mechanism (service tool) for which no
specific function except torque or force provision
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can be specified at an early stage in the project
development.
3.2.4 deliverable output force (F )
L
force at the mechanism or actuator output
3.2.5 elementary function
lowest level function
NOTE For example: One degree of freedom (rotation
and translation), torque or force generation,
sensing.
3.2.6 inertial resistance force (F )
D
force to accelerate the mass
3.2.7 inertial resistance torque(T )
D
torque to accelerate the inertia
3.2.8 fastener
item used to provide attachment of two or more separate parts, components or
assemblies
NOTE For example: Fasteners have the function of
locking the parts together and providing the
structural load path between the parts or, if used
as a securing part, to ensure proper locating of
the parts to be secured.
3.2.9 flushing or purging
control of the mechanism environment by enclosing the mechanism in specific
gaseous or fluid media which are surrounding, passing over or through the
mechanism
3.2.10 latching or locking
intentional constraining of one or more previously unconstrained degrees of
freedom which cannot be released without specific action
3.2.11 lubrication
use of specific material surface properties or an applied material between two
contacting or moving surfaces in order to reduce friction, wear or adhesion
3.2.12 mechanism
assembly of parts that are linked together to enable a relative motion
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3.2.13 off-loading
complete or partial unloading of a part or assembly from an initial pre-load
NOTE Off-loading is usually employed so as not to
expose a mechanisms part or assembly to launch
loads or other induced loads.
3.2.14 phase margin
indicator for the stability of dynamic control systems
3.2.15 positively locked
form-locked into a defined position from which release can only be obtained by
application of a specific actuation force
3.2.16 positive indication of status
direct monitoring of the state of the primary function at the output level of the
mechanism
3.2.17 primary function
high level function
NOTE For example: To hold, to release, to deploy, to
track, and to point.
3.2.18 safety critical mechanism
mechanical product having a critical or catastrophic hazard potential
3.2.19 threaded fastener
fastener with a threaded portion
NOTE For example: Screws, bolts and studs.
3.2.20 tribology
discipline that deals with the design, friction, wear and lubrication of interacting
surfaces in relative motion to each other
3.2.21 venting
compensation of the internal mechanism pressure environment with its
surrounding pressure environment
NOTE For example: Use of dedicated venting holes or
passages
3.3 Abbreviated terms
For the purpose of this Standard, the abbreviated terms from ECSS-S-ST-00-01
and the following apply:

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Abbreviation Meaning
analogue to digital
A/D
alternating current
AC
centre of gravity
COG
collected volatile condensable material
CVCM
digital to analogue
D/A
direct current
DC
design for minimum risk
DFMR
design limits loads
DLL
electromagnetic compatibility
EMC
electrostatic discharge
ESD
actuation force
F
F inertial resistance force
D
F
deliverable output force
L
failure mode effects and criticality analysis
FMECA
F
minimum actuator force required
min
factor of safety
FOS
F friction torque or force
R
ground support equipment
GSE
H
harness and other torque or force resistances
A
H adhesion torque or force
D
hardness Vickers
HV
H hysteresis torque or force
Y
inertia resistance (linear or angular)
I
Interface
I/F
low Earth orbit
LEO
mass
M
mechanism analytical verification
MAV
mechanism design description
MDD
mechanism user manual
MUM
multi-layer insulation
MLI
moment of inertia
MOI
margin of safety
MOS
strength safety margin
MS
safety critical mechanisms verification plan
MSVP
safety critical mechanisms verification report
MSVR
not applicable
n.a.
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Abbreviation Meaning
specific mechanism specification
SMS
recovered mass loss
RML
spring force
S
International System of Units
SI
spacecraft
S/C
specific mechanism specification
SMS
actuation torque
T
T
inertial resistance torque
D
T deliverable output torque
L
T
minimum actuator torque required
min
total mass loss
TML
ultraviolet
UV

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4
Requirements
4.1 Overview
This Standard addresses the requirements related to the generic aspects of the
engineering steps for the various engineering disciplines involved in the
achievement of the specified space mechanism performance.
The following requirements are identified considering interfaces and interactions
of mechanisms with those disciplines: thermal control, structures, functional
operations, materials and parts, pyrotechnics, propulsion, electrical and
electronics, and servo-control interactions. Where interactions with other
European space regulation are identified, reference is made to the related
regulation.
4.2 General requirements
4.2.1 Overview
Requirements of clause 4.2 cover the interaction of mechanisms engineering with
project management, processes, parts and components, product assurance, and
the related requirements affecting the conceptual definition, design, sizing,
analysis, development, and hardware production of mechanisms.
In view of the criticality of space mechanisms, which are often potential mission
critical single point failures, particular attention is placed upon the reliability and
redundancy of space mechanisms (see clause 4.2.5).
4.2.2 Mission specific requirements
a. A dedicated specific mechanism specification (SMS) shall be established in
conformance with Annex A for each individual mechanism in a project,
and agreed by the customer.
NOTE The SMS specification identifies all specific
requirements for a specific mechanism in a
project, that are not covered by the present
standard.
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4.2.3 Units
a. SI-units and associated symbols system shall be used.
4.2.4 Product characteristics
4.2.4.1 Marking and labelling
4.2.4.1.1 Specific identification
a. The identification of delivered pieces of hardware, parts, components,
sub-assemblies and assemblies shall carry at least the equipment title.
NOTE 1 For the identification of pieces of hardware,
parts, components, sub-assemblies, and
assemblies of the mechanism, see clause 5.3.1.5 of
ECSS-M-ST-40.
NOTE 2 The identification can be removable.
NOTE 3 The identification number and the equipment
title can be defined by the contracting authority.
4.2.4.1.2 Marking
a. Marking shall be applied on non-functional surfaces.
b. Bearings shall not be marked by the use of vibro-etch marks on the lateral
faces of the bearing races.
NOTE Etched marks on the lateral faces of the bearing
races affect the mounting tolerances of the
bearing in the housing and the bearing’s
tribological performance characteristics.
4.2.4.2 Parts and components
a. Existing parts and components used in mechanisms shall have been
previously qualified for the intended application according to a
qualification procedure approved by the customer.
NOTE Existing parts and components relate to parts
and components that were not specifically
developed for this specific application and cover
commercially available and off-the-shelf
hardware.
b. Existing parts and components used in mechanisms should have been
previously qualified at part or component level.
c. Flight proven parts and components should be used.
NOTE For the selection of not-flight proven parts and
components, see ECSS-Q-ST-60 for EEE
components and ECSS-Q-ST-70 for materials and
parts.
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4.2.4.3 Interchangeability
a. All items having the same identification number shall be functionally and
dimensionally interchangeable.
4.2.4.4 Maintainability
a. The mechanism should be designed to be maintenance free during storage
and ground life.
b. If the design is not maintenance free, the maintenance requirements shall
be documented in the SMS, justified, agreed by the customer.
c. If ground maintenance during storage or ground operation is not avoided,
the maintenance procedures shall be provided.
4.2.5 Reliability and redundancy
4.2.5.1 Reliability
a. For all mechanisms, which are critical to mission success, conformance to
the specified reliability figure shall be demonstrated according to the
following methods:
1. electronic components: by parts count as a minimum or other
methods approved by the customer;
2. mechanical parts: by stress analysis or other methods approved by
the customer;
3. mechanical limited-life: by life test approved by the customer.
b. For non-critical mechanisms, conformance to the reliability figure shall be
demonstrated by simplified methodsor other methods accepted by the
customer.
NOTE 1 The methods to achieve by design, derive by
analysis, and demonstrate by test the specified
reliability figures are presented in ECSS-Q-ST-30.
NOTE 2 An example of a simplified method is parts
count.
c. Failure of one part or element shall not result in consequential damage to
the equipment or other spacecraft components.
d. For structural reliability aspects ECSS-E-ST-32 shall apply.
e. For safety critical mechanisms in a crewed space mission where structural
failure can cause a catastrophic hazardous event, fasteners and load
carrying paths within mechanisms shall be designed in conformance with
fracture control requirements from ECSS-E-ST-32-01.
NOTE Definitions of catastrophic and critical hazardous
events are provided in ECSS-Q-ST-40. Fracture
control requirements are provided in ECSS-E-ST-
32-01.
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f. For safety critical mechanisms in case of non-crewed space mission the
applicability of fracture control requirements shall be specified by the
customer.
4.2.5.2 Redundancy
a. During the design of the mechanism, all single point failure modes shall be
identified.
b. All single points of failure should be eliminated by redundant components.
c. If single points of failure cannot be avoided, they shall be justified by the
supplier and approved by the customer.
d. Redundancy concepts shall be agreed by the customer.
NOTE Redundancy concepts are selected to minimize
the number of single points of failure and to
conform to the reliability requirements.
e. Where a single point failure mode is identified and redundancy is not
provided, compliance with the reliability, availability and maintainability
requirements specified in ECSS-Q-ST-30 shall be demonstrated.
f. Unless redundancy is achieved by the provision of a complete redundant
mechanism, active parts of mechanisms, such as sensors, motor windings,
brushes, actuators, switches and electronics, shall be redundant.
g. Failure of one element or part shall not prevent the other redundant
element or part from performing its intended function, nor the mechanism
from meeting its performance requirements specified in the specific
mechanism specification.
NOTE High-reliability of a mechanism can be
incorporated in a design by including component
redundancy or high design margins. The aim is
to deliver a design which is single failure
tolerant.
4.2.6 Flushing and purging
a. If operating the mechanism in air is detrimental to the performance of the
mechanism over its complete mission, means for flushing the critical parts
with an inert clean dry gas shall be provided.
NOTE Example of detrimental cause to operate the
mechanism in air is the presence of moisture or
other deleterious contamination.
b. Only lubricants qualified in respect to the residual humidity of the dry gas
shall be used.
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4.3 Mission and environments
a. The mechanism engineering shall consider every mission phase identified
for the specific space programme and conform to the related mission
requirements and environmental constraints.
NO
...

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