EN 16603-31-02:2015

SLOVENSKI STANDARD
01-november-2015
Vesoljska tehnika - Oprema za dvofazni toplotni transport
Space engineering - Two-phase heat transport equipment
Raumfahrttechnik - Ausrüstung für Zwei-Phasen-Wärmetransport
Ingénierie spatiale - Equipements de transfert de chaleur à deux phases
Ta slovenski standard je istoveten z: EN 16603-31-02:2015
ICS:
49.140 Vesoljski sistemi in operacije Space systems and
operations
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EUROPEAN STANDARD
EN 16603-31-02
NORME EUROPÉENNE
EUROPÄISCHE NORM
September 2015
ICS 49.140
English version
Space engineering - Two-phase heat transport equipment
Ingénierie spatiale - Equipements de transfert de chaleur à Raumfahrttechnik - Ausrüstung für Zwei-Phasen-
deux phases Wärmetransport
This European Standard was approved by CEN on 16 November 2014.

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, Slovakia,
Slovenia, Spain, Sweden, Switzerland, Turkey and United Kingdom.

CEN-CENELEC Management Centre:
Avenue Marnix 17, B-1000 Brussels
© 2015 CEN/CENELEC All rights of exploitation in any form and by any means reserved Ref. No. EN 16603-31-02:2015 E
worldwide for CEN national Members and for CENELEC
Members.
Table of contents
European foreword . 5
Introduction . 5
1 Scope . 7
2 Normative references . 8
3 Terms, definitions and abbreviated terms . 9
3.1 Terms defined in other standards . 9
3.2 Terms specific to the present standard . 9
3.3 Abbreviated terms. 13
4 TPHTE qualification principles . 14
4.1 TPHTE categorization . 14
4.2 Involved organizations . 14
4.3 Generic requirements in this standard . 15
4.4 Processes, number of qualification units . 16
4.5 Thermal and mechanical qualification . 16
4.5.1 Temperature range . 16
4.5.2 Mechanical qualification . 18
5 Requirements . 20
5.1 Technical requirements specification (TS) . 20
5.1.1 General . 20
5.1.2 Requirements to the TS . 20
5.1.3 Requirements for formulating technical requirements . 21
5.2 Materials, parts and processes . 22
5.3 General qualification requirements . 22
5.3.1 Qualification process . 22
5.3.2 Supporting infrastructure – Tools and test equipment . 22
5.4 Qualification process selection . 22
5.5 Qualification stage . 24
5.5.1 General . 24
5.5.2 Quality audits . 25
5.5.3 Qualification methods . 25
5.5.4 Full and delta qualification programme . 27
5.5.5 Performance requirements . 27
5.6 Qualification test programme . 29
5.6.1 Number of qualification units . 29
5.6.2 Test sequence . 29
5.6.3 Test requirements . 33
5.6.4 Physical properties measurement . 36
5.6.5 Proof pressure test . 37
5.6.6 Pressure cycle test . 37
5.6.7 Burst pressure test . 37
5.6.8 Leak test . 38
5.6.9 Thermal performance test . 39
5.6.10 Mechanical tests . 41
5.6.11 Thermal cycle test . 43
5.6.12 Aging and life tests . 43
5.6.13 Gas plug test . 44
5.6.14 Reduced thermal performance test . 44
5.7 Operating procedures . 45
5.8 Storage . 45
5.9 Documentation . 45
5.9.1 Documentation summary . 45
5.9.2 Specific documentation requirements. 45
Annex A (normative) Technical requirements specification (TS) – DRD . 48
Annex B (normative) Verification plan (VP) – DRD . 51
Annex C (normative) Review-of-design report (RRPT) - DRD . 54
Annex D (normative) Inspection report (IRPT) – DRD . 56
Annex E (normative) Test specification (TSPE) – DRD . 58
Annex F (normative) Test procedure (TPRO) – DRD . 61
Annex G (normative) Test report (TRPT) – DRD . 64
Annex H (normative) Verification report (VRPT) – DRD. 66
Bibliography . 68

Figures
Figure 3-1: Tilt definition for HP . 12
Figure 3-2: Tilt definition for LHP . 12
Figure 4-1: Categories of TPHTE (two-phase heat transport equipment) . 15
Figure 4-2: Figure-of-merit (G) for some TPHTE fluids . 17
Figure 4-3: Definition of temperature and performance ranges for a HP . 18
Figure 5-1: Selection of qualification process . 24
Figure 5-2: Qualification test sequence for HP . 31
Figure 5-3: Qualification test sequence for CDL . 32

Tables
Table 5-1: Categories of two-phase heat transport equipment according to heritage
(derived from ECSS-E-ST-10-02C, Table 5-1) . 23
Table 5-2: Allowable tolerances . 34
Table 5-3: Measurement accuracy . 36
Table 5-4: Equipment resonance search test levels . 42
Table 5-5: Sinusoidal vibration qualification test levels . 42
Table 5-6: Random vibration qualification test levels . 43
Table 5-7: TPHTE documentation . 47

European foreword
This document (EN 16603-31-02:2015) has been prepared by Technical
Committee CEN/CLC/TC 5 “Space”, the secretariat of which is held by DIN.
This standard (EN 16603-31-02:2015) originates from ECSS-E-ST-31-02C.
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 March
2016, and conflicting national standards shall be withdrawn at the latest by
March 2016.
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 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,
Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and the United
Kingdom.
Introduction
This Standard is based on ESA PSS-49, Issue 2 “Heat pipe qualification
requirements”, written 1983, when the need for heat pipes in several ESA
projects had been identified. At that time a number of European development
activities were initiated to provide qualified heat pipes for these programmes,
which culminated in a first heat pipe application on a European spacecraft in
1981 (MARECS, BR-200, ESA Achievements - More Than Thirty Years of
Pioneering Space Activity, ESA November 30, 2001), followed by a first major
application on a European communication satellite in 1987 (TV-SAT 1, German
Communication Satellites).
ESA PSS-49 was published at a time, when knowledge of heat pipe technology
started to evolve from work of a few laboratories in Europe (IKE, University
Stuttgart, EURATOM Research Centre, Ispra). Several wick designs, material
combinations and heat carrier fluids were investigated and many process
related issues remained to be solved. From today’s view point the qualification
requirements of ESA PSS-49 appear therefore very detailed, exhaustive and in
some cases disproportionate in an effort to cover any not yet fully understood
phenomena. As examples the specified number of qualification units (14), the
number of required thermal cycles (800) and the extensive mechanical testing
(50 g constant acceleration, high level sine and random vibration) can be cited.
The present Standard takes advantage of valid requirements of ESA PSS-49, but
reflects at the same time today’s advanced knowledge of two-phase cooling
technology, which can be found with European manufacturers. This includes
experience to select proven material combinations, reliable wick and container
designs, to apply well-established manufacturing and testing processes, and
develop reliable analysis tools to predict in-orbit performance of flight
hardware. The experience is also based on numerous successful two-phase
cooling system application in European spacecraft over the last 20 years.
Besides stream-lining the ESA PSS-49, to arrive at today’s accepted set of heat
pipe qualification requirements, the following features have also been taken
into account:
• Inclusion of qualification requirements for two-phase loops (CPL, LHP),
• Reference to applicable requirements in other ECSS documents,
• Formatting to recent ECSS template in order to produce a document,
which can be used in business agreements between customer and
supplier.
Scope
This standard defines requirements for two-phase heat transportation
equipment (TPHTE), for use in spacecraft thermal control.
This standard is applicable to new hardware qualification activities.
Requirements for mechanical pump driven loops (MPDL) are not included in
the present version of this Standard.
This standard includes definitions, requirements and DRDs from ECSS-E-ST-10-
02, ECSS-E-ST-10-03, and ECSS-E-ST-10-06 applicable to TPHTE qualification.
Therefore, these three standards are not applicable to the qualification of
TPHTE.
This standard also includes definitions and part of the requirements of ECSS-E-
ST-32-02 applicable to TPHTE qualification. ECSS-E-ST-32-02 is therefore
applicable to the qualification of TPHTE.
This standard does not include requirements for acceptance of TPHTE.
This standard may be tailored for the specific characteristic and constrains of a
space project in conformance with ECSS-S-ST-00.
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 revision 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 more 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 16603-31 ECSS-E-ST-31 Space engineering - Thermal control general
requirements
EN 16603-32 ECSS-E-ST-32 Space engineering - Structural general requirements
EN 16603-32-01 ECSS-E-ST-32-01 Space engineering- Fracture control
EN 16603-32-02 ECSS-E-ST-32-02 Space engineering - Structural design and
verification of pressurized hardware
EN 16602-70 ECSS-Q-ST-70 Space product assurance - Materials, mechanical
parts and processes
EN 9100:2009 Aerospace series - Quality management systems -
Requirements for Aviation, Space and Defense
Organizations
Terms, definitions and abbreviated terms
3.1 Terms defined in other standards
For the purpose of this Standard, the terms and definitions from ECSS-E-ST-00-01
apply.
For the purpose of this standard, the following terms and definitions from
ECSS-E-ST-10-02 apply:
analysis
qualification stage
review-of-design (ROD)
For the purpose of this standard, the following terms and definitions from
ECSS-E-ST-32-02 apply:
burst pressure
differential pressure
external pressure
internal pressure
leak-before-burst (LBB)
pressure vessel (PV)
pressurized hardware (PH)
proof test
3.2 Terms specific to the present standard
3.2.1 capillary driven loop (CDL)
TPL, in which fluid circulation is accomplished by capillary action (capillary
pump)
NOTE See TPL definition in 3.2.21.
3.2.2 capillary pumped loop (CPL)
CDL with the fluid reservoir separated from the evaporator and without a
capillary link to the evaporator
NOTE See CDL definition in 3.2.1.
3.2.3 constant conductance heat pipe (CCHP)
heat pipe with a fixed thermal conductance between evaporator and condenser
at a given saturation temperature
NOTE See heat pipe definition in 3.2.7.
3.2.4 dry-out
depletion of liquid in the evaporator section at high heat input when the
capillary pressure gain becomes lower than the pressure drop in the circulating
fluid
3.2.5 effective length
heat pipe length between middle of evaporator and middle of condenser for
configurations with one evaporator and one condenser only
NOTE Used to determine the heat pipe transport
capability (see 3.2.10).
3.2.6 exposure temperature range
maximum temperature range to which a TPHTE is exposed during its product
life cycle and which is relevant for thermo-mechanical qualification
NOTE 1 The internal pressure at the maximum temperature
of this range defines the MDP for the pressure
vessel qualification of a TPHTE.
NOTE 2 The extreme temperatures of this range can be
below freezing and / or above critical temperatures
of the working fluid.
NOTE 3 In other technical domains, this temperature range
is typically called non-operating temperature
range (see clause 4 for additional explanation).
3.2.7 heat pipe (HP)
TPHTE consisting of a single container with liquid and vapour passages
arranged in such a way that the two fluid phases move in counter flow
NOTE 1 See TPHTE definition in 3.2.20.
NOTE 2 The capillary structure in a heat pipe extends over
the entire container length.
3.2.8 heat pipe diode (HPD)
heat pipe, which transports heat based on evaporation and condensation only
in one direction
NOTE See heat pipe definition in 3.2.7.
3.2.9 loop heat pipe (LHP)
CDL with the fluid reservoir as integral part of the evaporator
NOTE 1 See CDL definition in 3.2.1.
NOTE 2 The reservoir can be separated, but has a capillary
link to the evaporator.
3.2.10 heat transport capability
maximum amount of heat, which can be transported in a TPHTE from the
evaporator to the condenser
NOTE For heat pipes it is the maximum heat load
expressed in [Wm] (transported heat x effective
length).
3.2.11 maximum design pressure (MDP)
maximum allowed pressure inside a TPHTE during product life cycle
NOTE The product life cycle starts after acceptance of
the product for flight.
3.2.12 mechanical pump driven loop (MPDL)
TPL, in which fluid circulation is accomplished by a mechanical pump
NOTE See TPL definitions in 3.2.21.
3.2.13 product life cycle
product life starting from the delivery of the TPHTE hardware until end of
service live
3.2.14 reflux mode
operational mode, where the liquid is returned from the condenser to the
evaporator by gravitational forces and not by capillary forces
3.2.15 start-up
operational phase starting with initial supply of heat to the evaporator until
nominal operational conditions of the device are established
3.2.16 sub-cooling
temperature difference between average CDL reservoir temperature and the
temperature of the liquid line at the inlet to the reservoir
NOTE The average CDL reservoir temperature
represents the saturation temperature inside the
reservoir.
3.2.17 thermal performance temperature range
temperature range for which a TPHTE is thermally qualified
NOTE In the thermal performance temperature range
a thermal performance map exists.
3.2.18 tilt for HP
height of the evaporator (highest point) above the condenser (lowest point)
during ground testing
NOTE This definition is valid for a configuration with
one evaporator and one condenser (see Figure
3-1).
evaporator
condenser
Figure 3-1: Tilt definition for HP
3.2.19 tilt for LHP
height of the evaporator (highest point) above the reservoir (lowest point)
during ground testing
NOTE See Figure 3-2.
Figure 3-2: Tilt definition for LHP
3.2.20 two-phase heat transport equipment (TPHTE)
hermetically closed system filled with a working fluid and transporting thermal
energy by a continuous evaporation/condensation process using the latent heat
of the fluid
NOTE 1 A fluid evaporates in the heat input zone
(evaporator) and condenses in the heat output
zone (condenser).
NOTE 2 This is in contrast to a single-phase loop where the
sensible heat of a liquid is transported (a liquid
heats up in the heat input zone and cools down in
the heat output zone).
3.2.21 two-phase loop (TPL)
TPHTE with physically separated vapour and liquid transport lines forming a
closed loop
NOTE See TPHTE definition in 3.2.20.
3.2.22 variable conductance heat pipe (VCHP)
heat pipe with an additional non-condensable gas reservoir allowing a variable
thermal conductance between evaporator and condenser
NOTE 1 See heat pipe definition in 3.2.7.
NOTE 2 The variation in thermal conductance is generally
accomplished by regulating the volume of a non-
condensable gas plug reaching into the condenser
zone, which in turn varies the effective condenser
length.
NOTE 3 The variation of the gas volume can be performed
by active or passive means.
3.3 Abbreviated terms
The following abbreviations are defined and used within this standard:
Abbreviation Meaning
constant conductance heat pipe
CCHP
capillary driven loop
CDL
capillary pumped loop
CPL
coefficient of thermal expansion
CTE
document requirements definition
DRD
heat pipe
HP
heat pipe diode
HPD
leak before burst
LBB
loop heat pipe
LHP
maximum design pressure
MDP
mechanical pump driven loop
MPDL
metallic special pressurized equipment
MSPE
non-destructive inspection
NDI
pressurized hardware
PH
review-of-design
ROD
special pressurized equipment
SPE
thermal control (sub)system
TCS
two-phase heat transport equipment
TPHTE
two-phase loop
TPL
technical requirement specification
TS
variable conductance heat pipe
VCHP
verification plan
VP
TPHTE qualification principles
4.1 TPHTE categorization
TPHTE are considered special pressurized hardware, as defined in clause 3.
Requirements of ECSS-E-ST-32-02 are included in this Standard for this reason.
The TPHTE are categorized in Figure 4-1 according to their design and
functional principle.
Heat pipes consist of a single container with a capillary structure extending
over the entire container length. Liquid and vapour passages are arranged in
such a way that the two fluid phases move in counter flow.
Capillary driven loops (CDL) have separate evaporator and condenser sections,
which are connected by dedicated vapour and liquid tubing. At least one
capillary structure is located in the evaporator section, which serves as capillary
pump to circulate the fluid in a true loop configuration.
The mechanically pumped two-phase loop (MPDL) has a configuration, which
is similar to the CDL, except that the circulation of the fluid is accomplished by
a mechanical pump.
NOTE Requirements for MPDL are not included in the
present version of this Standard.
4.2 Involved organizations
The qualification process of TPHTE is generally carried out by a specialized
equipment manufacturer (called in this document “supplier”) and controlled by
the qualification authority, which is called in this document the “customer”.
The qualification activity is embedded in the supplier’s product assurance and
quality organization and in most cases the supplier's quality assurance plan has
been established and approved for space activities independently from the
TPHTE qualification process specified in this document. It is the task of the
supplier’s PA authority to introduce / approve adequate product assurance
provisions at his subcontractor(s). The existence of an approved PA Plan is
precondition for commencing qualification activities.
Figure 4-1: Categories of TPHTE (two-phase heat transport equipment)
4.3 Generic requirements in this standard
The present document provides generic, i.e. not project specific requirements
for formal qualification of TPHTE. It is therefore important to select overall and
enveloping qualification requirements in order to support a maximum of
spacecraft application without the need for delta qualification.
4.4 Processes, number of qualification units
The qualification of TPHTE is based on qualified manufacturing processes (e.g.
cleaning, surface treatment, welding and leak testing) and covers in general the
following areas:
• Performance over long operation time (compatibility between fluid and
wall material, space radiation, leak tightness)
• Mechanical performance (strength, pressurized hardware)
• Thermal performance (e.g. heat transport capability, start-up behaviour,
heat transfer coefficients)
In this context the number of TPHTE units to be produced for the qualification
program are evaluated and selected by the supplier. There are no general
applicable sources, which specify the minimum of units to be used to undergo
identical qualification testing in order to arrive at a successful qualified
product. The question to be answered for each TPHTE configuration is: How
many identical units need to be built and tested in order to verify that
production processes provide reproducible performance results.
The following are possible selection criteria:
• Experience of the manufacturer in production of similar products,
• Simplicity of the configuration,
• TPHTE design features, which have inherent capability for good
repeatability of the production processes (e.g. simple axial grooved heat
pipes).
This Standard specifies the number of needed units submitted to the
qualification process for configurations, which are currently used in several
spacecraft applications. It is recommended that the supplier performs the
selection for other configurations and provide argumentation to the customer
for agreement of his choice.
Compared to full qualification of a new product the number of units can be
reduced for delta qualification of an existing but modified product.
4.5 Thermal and mechanical qualification
4.5.1 Temperature range
In contrast to most of electronic equipment the performance of a TPHTE varies
with its operating temperature, because properties of the used heat carrier are
temperature dependent. For heat pipes as an example, important fluid
properties can be grouped into a figure-of-merit (G), which is the product of
surface tension, heat of vaporization and liquid density divided by the liquid
viscosity (for more information see references in Bibliography). G is plotted for
some fluids over the temperature in Figure 4-2. The heat transport capability of
a capillary pumped loop is proportional to these curves.
Figure 4-2: Figure-of-merit (G) for some TPHTE fluids
Generally, the applicable temperature range of a TPHTE is subdivided into a
thermally and a mechanically relevant regime.
The thermal performance temperature range, which is used for thermal
qualification, is defined within the theoretical operating temperature range,
confined by the freezing and the critical temperature of the used fluid. Lower
and upper temperature limits of the qualification range are selected in such a
way that a useful map of thermal performance data can be established. Within
this range the maximum transport capability for qualification will be
determined. For a specific space application the operating temperature range
(within the thermal performance temperature range) and the maximum
required heat transport capability are specified.
For thermo-mechanical qualification the temperature range is relevant, to which
the device is exposed to during the life cycle. In most cases this exposure
temperature range is wider than the above-mentioned thermal performance
temperature range. The minimum temperature of this range can be below the
freezing temperature of the used heat carrier and it is important to take into
account possible damage caused by the freezing or thawing effects. The upper
exposure temperature can be even above the critical temperature of the heat
carrier. This temperature determines in general the maximum internal pressure
for design and qualification of the device.
The mentioned temperature ranges and associated heat transport capabilities
are illustrated in Figure 4-3.

Legend
Q Maximum transport capability for qualification
max,qual
Q Maximum transport capability for acceptance (specified for a specific project)
max,acc
T , T Freezing and critical temperature of a selected fluid
F C
T T Minimum and maximum performance temperature
P, min, P, max
T T Minimum and maximum acceptance temperature (specified for a specific project)
Ac, min, Ac, max
T P,min  T P,max Performance temperature range
T Ac,min  T Ac,max Acceptance temperature range (specified for a specific project)
Figure 4-3: Definition of temperature and performance ranges for a HP
4.5.2 Mechanical qualification
TPHTE are classified as pressurized component and relevant mechanical
requirements are specified in ECSS-ST-E-32-02 and are applied in the present
Standard for all TPHTE types.
For qualification of a TPHTE as pressurized component the main characteristic
is the internal pressure, which varies in relation to the exposure temperature of
the unit (temperature dependent saturation pressure of the heat carrier liquid).
ECSS-ST-E-32-02 specifies qualification requirements for heat pipes (see figure
4.12). The present Standard selects qualification requirements for TPHTE,
which have seen proof pressure tests ≥ 1,5 MDP. Testing is the preferred
method rather than qualification by fracture control analysis.
For qualifying a TPHTE with respect to external mechanical environment the
following mechanical tests are considered:
• Constant or static acceleration
• Sine vibration
• Random vibration
For these tests the qualification unit needs to be rigidly mounted to the test
equipment (vibration table). However, such mounting provisions can have only
reduced similarity to real applications in spacecrafts and the meaningfulness of
such tests is, therefore, very often reason for discussion under experts. For heat
pipes it is common understanding not to perform these tests on long heat pipe
profiles for the following reasons:
• The length of the test heat pipe is adapted to the test equipment and is
therefore shorter as in many realistic spacecraft applications.
• The application of heat pipe is often for embedding them in sandwich
structures. Mechanical loads for these applications are quite different as
can be simulated with a rigidly fixed single heat pipe profile.
• Several capillary structures, in particular axial groove heat pipes, are
quite insensitive to mechanical loads and tests as suggested in existing
procedures can be unnecessary.
For many TPHTE applications (in particular for devices with simple capillary
structures, e.g. axial grooves) the formal mechanical qualification can be
therefore performed with the first structural model on satellite level. In case the
risk for such a late qualification is high, pre-qualification can be performed on
unit or part level in particular for the following cases:
• The TPHTE, in particular a heat pipe, has a capillary structure, which is
sensitive towards mechanical loads, e.g. arterial wick. In such a case a
short piece of the heat pipe profile is selected for mechanical qualification
testing (sine, random vibration).
• An evaporator of a LHP or CPL can be separately tested (sine, random
vibration) to verify that mechanical requirements are met.
• Equally this can be true for a two-phase loop condenser, in particular for
configurations where the condenser tubing is embedded into a structural
panel.
The Standard does not therefore not specify at which model level vibration
testing is to be performed. The supplier and customer are asked to agree on a
logical qualification plan, which may include testing at higher than equipment
level.
Requirements
5.1 Technical requirements specification (TS)
5.1.1 General
a. The qualification process shall be based on a technical requirements
specification, approved by the customer.
NOTE Usually the technical specification evolves from
the functional requirements of the customer
and defines the technical performances for the
proposed solution as part of a business
agreement.
b. The technical requirements specification specified in 5.1.1a shall be
written in accordance with DRD in Annex A.
5.1.2 Requirements to the TS
a. The specification shall be identifiable, referable and related to a TPHTE
product.
b. The following entity shall be responsible for the TS:
1. the supplier for a generic TPHTE specification, which is not related
to a specific application;
2. the customer for a specific TPHTE specification, which is related to
a specific application.
NOTE A delta qualification can be necessary, if the
generic specification does not completely meet
the requirements for a specific application.
c. Each technical requirement shall be separately stated.
d. Abbreviated terms used in requirements shall be defined in a dedicated
section of the specification.
e. The technical requirements shall be consistent and not in conflict with the
other requirements within the specification.
f. The technical requirements shall not be in conflict with other
requirements contained in business agreement documents.
g. The specification shall be complete in terms of applicable technical
requirements and reference to applicable documents.
h. The specification shall be under configuration management.
i. Quantity of units required for the qualification process shall be specified
in the TS.
NOTE TS exclude requirements such as cost, methods
of payment, time or place of delivery.
5.1.3 Requirements for formulating technical
requirements
a. Each technical requirement shall be described in quantifiable terms.
b. The technical requirements shall be unambiguous.
c. Each technical requirement shall be unique.
d. A unique identifier shall be assigned to each technical requirement.
e. Each technical requirement shall be separately stated.
f. A technical requirement shall be verifiable using one or more approved
verification methods.
g. The tolerance shall be specified for each parameter/variable.
NOTE The technical requirement tolerance is a range
of values within which the conformity to the
requirement is accepted.
h. Technical requirements should be stated in performance or “what-is-
necessary” terms, as opposed to “how-to" perform a task, unless the exact
steps in performance of the task are essential to ensure the proper
functioning of the product.
i. Technical requirements should be expressed in a positive way, as a
complete sentence (with a verb and a noun).
j. The verbal form “shall” shall be used whenever a provision is a
requirement.
k. The verbal form “should” shall be used whenever a provision is a
recommendation.
l. The verbal form “may” shall be used whenever a provision is a
permission.
m. The verbal form “can” shall be used to indicate possibility or capability.
n. The following terms shall not be used in a TS requirement: “and/or”,
“etc”, “goal”, “shall be included but not limited to”, “relevant”,
“necessary”, “appropriate”, “as far as possible”, “optimize”, “minimize”,
“maximize”, “typical”, “rapid”, “user-friendly”, “easy”, “sufficient”,
“enough”, “suitable”, “satisfactory”, adequate”, “quick”, “first rate”,
“best possible”, “great”, “small”, “large”, and “state of the art”.
5.2 Materials, parts and processes
a. Materials, parts and processes for TPHTE to be qualified shall be
documented in the following lists (see Table 5-7):
1. Declared materials list
2. Declared mechanical parts list
3. Declared processes list
5.3 General qualification requirements
5.3.1 Qualification process
a. The qualification stage shall be completed before launch.
5.3.2 Supporting infrastructure – Tools and test
equipment
a. Tools to be used to support the qualification process shall be validated
for their intended use.
b. The validation shall be performed under expected environmental
conditions and operational constraints.
c. Compatibility of tools and test equipment interfaces with flight
qualification hardware shall be verified by test.
d. Calibration of laboratory equipment shall be verified prior to their use.
e. Tools and test equipment that is modified and used in a new application
shall be re-verified according to 5.3.2a to 5.3.2d.
f. Test facilities, tools and instrumentation shall be designed to avoid
adverse effects on the qualification objectives.
NOTE Examples of these are: Thermocouples, strain
gauges, heater mounting, cooling devices,
support structures.
5.4 Qualification process selection
a. The scope of the qualification process shall be adapted to the
qualification heritage of the product.
b. For categorization of the heritage the product categories of Table 5-1 shall
be used.
c. The qualification process shall be structured according to Figure 5-1.
Table 5-1: Categories of two-phase heat transport equipment according to heritage
(derived from ECSS-E-ST-10-02C, Table 5-1)
Description Qualification programme Remarks related to the present
Standard
A Off-the-shelf product without None
modifications and
 The product is qualified to
requirements at least as severe as
those imposed by the actual
technical specification
 The product is produced by the
same manufacturer and using
identical tools and manufacturing
processes
B Off-the-shelf product without Delta qualification This category relates for example to
modifications. programme, decided on a TPHTE hardware, which is identical
case-by-case basis in to already qualified hardware but has
However:
agreement between the been qualified to lower mechanical
 The product is qualified to
customer and the supplier loads or narrower operating
requirements less severe or
temperature ranges as required by an
different to those imposed by the
actual project.
actual technical specification
The category relates also to situations,
Or
where TPHTE manufacturing
 The product is produced by a technology is transferred from a
different manufacturer or using qualified supplier to a new
different tools and manufacturing
manufacturer.
processes
*) Any substitution parts and
Or materials fulfilling the same
procurement specification does not
 The product has substitution parts
require delta-qualification.
and materials with equivalent
reliability *)
C Off-the-shelf product with design Delta or full qualification Examples for category C are:
modifications programme, decided on a
Heat pipes with identical capillary
case-by-case basis depending
structure but different diameters,
on the impact of the
smaller bent radius,
modification in agreement
CDL with different fluid line
between the customer and the
configurations or dimensions or
supplier
different condenser configurations
(radiator lay out).
D New designed and developed product. Full qualification programme. Applicable for any new developed
TPHTE, including existing systems
with new capillary structures or
material combinations.
Category
TPHTE to be
qualified
Review-of-design
(Clause 5.5.3.4)
Yes
Category A
No qualification
equipment?
programme required
No
Delta qualification
Similarity analysis
Yes
Category B programme
(Clause 5.5.3.3.2)
(Clause 5.5.4.2)
equipment?
No
Delta qualification
programme
Yes Similarity analysis
Category C
(Clause 5.5.4.2)
(Clause 5.5.3.3.2)
equipment?
or Full qualification
programme
(Clause 5.5.4.1)
No
Category D
equipment
Full qualification
programme
(Clause 5.5.4.1)
For category definition see Table 5-1.
Figure 5-1: Selection
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