ISO 5879:2023
(Main)Space systems — Ground test for the separation between a launch vehicle and a spacecraft — Requirements for combined separation tests, horizontal separation tests and individual falling separation tests
Space systems — Ground test for the separation between a launch vehicle and a spacecraft — Requirements for combined separation tests, horizontal separation tests and individual falling separation tests
This document provides the test requirements of three typical separation test methods, which are the combined separation test, the horizontal separation test, the individual falling separation test, for the separation between the launch vehicle (LV) and the spacecraft (or between stages of a prototype LV model). It also provides the requirements for the separation test unit, test data, test timing and sequence, pre-test simulation, test environment, exception handling, test results assessment, test documentation, test facilities, test installation, preliminary adjustment of the test setup, measurement and data acquisition. This document is applicable to test providers and interested parties to implement the separation test between the launch vehicle and the spacecraft.
Systèmes spatiaux — Essais au sol pour la séparation entre un lanceur et un engin spatial — Exigences relatives aux essais de séparation combinée, aux essais de séparation horizontale et aux essais de séparation par chute individuelle
General Information
Standards Content (Sample)
INTERNATIONAL ISO
STANDARD 5879
First edition
2023-08
Space systems — Ground test for the
separation between a launch vehicle
and a spacecraft — Requirements for
combined separation tests, horizontal
separation tests and individual falling
separation tests
Systèmes spatiaux — Essais au sol pour la séparation entre un
lanceur et un engin spatial — Exigences relatives aux essais de
séparation combinée, aux essais de séparation horizontale et aux
essais de séparation par chute individuelle
Reference number
© ISO 2023
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ii
Contents Page
Foreword .v
Introduction . vi
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Symbols and abbreviated terms.2
5 General requirements . 3
5.1 Purposes of separation testing . 3
5.1.1 General . 3
5.1.2 Verification purposes . 3
5.1.3 Diagnostic purposes . 3
5.1.4 Tailoring guide . 3
5.2 General separation test process . 3
5.2.1 General . 3
5.2.2 Test documentation preparation and pre-test simulation . 4
5.2.3 Test implementation . 4
5.2.4 Test results data collection . 4
5.2.5 Test results evaluation . 4
5.3 Test articles under separation test . 5
5.3.1 Specification of separation test unit . 5
5.3.2 Requirements for test articles . 6
5.3.3 Technical safety requirements for test articles . 6
5.4 Data requirements . 7
5.4.1 Test data . 7
5.4.2 Separation movement data . 7
5.4.3 Separation shock response data . 7
5.4.4 The dedicated data by test requirements . 7
5.5 Test timing and sequence . 7
5.6 Requirements for pre-test simulation . 7
5.6.1 Purposes of pre-test simulation . 7
5.6.2 Requirements for the simulation modelling . 8
5.6.3 Requirements for the simulation solver . 9
5.6.4 Requirements for the simulation results . 9
5.6.5 Validation of the simulation results . 9
5.7 Requirements for test environment . 9
5.8 Exception handling . 9
5.8.1 Test interruption . 9
5.8.2 Interruption handling . 9
5.9 Test results assessment . 9
5.10 Test documentation . . 9
6 Test facilities .10
6.1 General . 10
6.2 Calibration requirements. 10
6.3 Control instrumentation requirements . 10
6.3.1 Requirements for electrical power source . 10
6.3.2 Requirements for hold-down/release mechanism controller and
connection cables . 10
6.4 Measurement instrumentation and equipment requirements . 11
6.4.1 General . 11
6.4.2 Requirements for accelerometer for translational motion measurement . 11
6.4.3 Requirements for high-speed video camera. 11
6.4.4 Requirements for rate gyroscope .12
iii
6.4.5 Requirements for timing measurement system.12
6.4.6 Requirements for optical displacement measurement system .12
6.4.7 Requirements for shock measurement system .13
6.5 Testing fixture requirements . 14
6.5.1 General . 14
6.5.2 Requirements for the test scaffolding . 14
6.5.3 Requirements for the angular rotation mechanism .15
6.5.4 Requirements for the release mechanism between test fixture and test
articles .15
6.5.5 Test article capture system requirements . 15
6.6 Technical safety requirements for test facilities . 16
6.6.1 Consolidation and support of test scaffolding . 16
6.6.2 Confirmation of safety status of test facilities . 16
6.6.3 Test area . 16
7 Test installation .16
7.1 General . 16
7.2 Test articles installation requirements . 16
7.2.1 Installation process . 16
7.2.2 Functional constraints . 16
7.3 Sensors installation requirements . 16
7.3.1 Accelerometers for translational motion measurement installation
requirements . 16
7.3.2 Rate gyroscopes installation requirements . 17
7.3.3 shock accelerometers installation requirements . 17
7.4 High-speed video camera installation requirements . 17
7.4.1 Camera arrangement . 17
7.4.2 Installation location . 18
7.4.3 Purpose . 18
7.4.4 Luminance . 18
7.5 Technical safety requirements for test installation . 18
7.5.1 Training and qualification . 18
7.5.2 Working high above the ground . 18
8 Requirements for the preliminary adjustment of the test setup .18
9 Measurement and data acquisition requirements .18
9.1 General . 18
9.2 Acquisition and processing requirements for the dedicated data by test
requirements . . . 19
9.3 Acquisition and processing requirements for separation movement data . 19
9.3.1 Noise reduction . . . 19
9.3.2 Data format . 19
9.4 Acquisition and processing requirements for shock response data . 19
9.4.1 Shock response data. 19
9.4.2 Detection of anomalies . 19
9.4.3 Processing requirements . 19
9.4.4 SRS values . 19
9.4.5 Time data format . . 19
9.4.6 Shock response spectrum . 20
Annex A (informative) Overview and interdependencies of test methods .21
Annex B (informative) Combined separation test.23
Annex C (informative) Individual falling separation test .25
Annex D (informative) Horizontal separation test .27
Annex E (informative) The implementation of separation test .30
Bibliography .32
iv
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
bodies (ISO member bodies). The work of preparing International Standards is normally carried out
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Subcommittee SC 14, Space systems and operations.
Any feedback or questions on this document should be directed to the user’s national standards body. A
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v
Introduction
The separation between the launch vehicle and the spacecraft on orbit is a critical activity for a
successful orbit injection. Any failure during the separation can cause serious consequences. A
separation test on ground between the spacecraft and the launch vehicle is an effective way to
simulate and test the characteristics of the separation, to reveal the risk of failure of the separation
system between the launch vehicle and the spacecraft, and to improve the separation function during
the separation on orbit. This document provides three typical separation test methods, which are the
combined separation test, the horizontal separation test and the individual falling separation test, for
different application scenarios.
The overview and interdependencies of test methods are illustrated in Annex A. For the testing of
separation movements and separation dynamics between launch vehicle and spacecraft with zero-
gravity effect or no acceleration conditions at the time of separation, the separation test may take
the form of combined separation test or horizontal separation test as illustrated in Annex B and
Annex D respectively. For the testing of separation with purposes of fit-check and shock-response-level
confirmation, the test may take the form of individual falling separation test as illustrated in Annex C.
Apart from these three separation test methods, there are many other methods of verifying separation
systems and processes, such as modelling the systems or processes, comparing similarity with existing
systems or processes, which may apply to different scenarios with consistency. This document does
not deny the use of these useful methods in the simulating and testing of the characteristics of the
separation.
The technical requirements in this document may be tailored to meet the objectives of tests as the
separation objectives can be different for different projects or for different development stages.
vi
INTERNATIONAL STANDARD ISO 5879:2023(E)
Space systems — Ground test for the separation between
a launch vehicle and a spacecraft — Requirements for
combined separation tests, horizontal separation tests and
individual falling separation tests
1 Scope
This document provides the test requirements of three typical separation test methods, which are
the combined separation test, the horizontal separation test, the individual falling separation test, for
the separation between the launch vehicle (LV) and the spacecraft (or between stages of a prototype
LV model). It also provides the requirements for the separation test unit, test data, test timing and
sequence, pre-test simulation, test environment, exception handling, test results assessment, test
documentation, test facilities, test installation, preliminary adjustment of the test setup, measurement
and data acquisition.
This document is applicable to test providers and interested parties to implement the separation test
between the launch vehicle and the spacecraft.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements of this document. For dated references, only the edition cited applies. For
undated references, the latest edition of the referenced document (including any amendments) applies.
ISO 14620-1:2018, Space systems — Safety requirements — Part 1: System safety
ISO 15864:2021, Space systems — General test methods for spacecraft, subsystems and units
ISO 22137, Space systems — Program management — Test reviews
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
ISO and IEC maintain terminology databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at https:// www .electropedia .org/
3.1
combined separation test
test in which a combination of spacecraft parts and launch vehicle parts drops simultaneously from the
hanging point
Note 1 to entry: The test articles finish the separation movements before being captured during the separation
test.
3.2
fit check
check to verity the matching consistencies of the electrical interface and the mechanical interface
between the spacecraft and the launch vehicle to some degree
Note 1 to entry: This check usually consists of an electrical interface check and a mechanical interface check
between the spacecraft and the launch vehicle before the separation test.
3.3
horizontal separation test
test in which a combination of spacecraft parts and launch vehicle parts is separated horizontally
3.4
individual falling separation test
test in which a combination of spacecraft parts and launch vehicle parts is separated vertically and
either spacecraft parts or launch vehicle parts fall down from the combination
3.5
launch vehicle stages separation system
assembly of functionally related subsystems and/or units for the separation between launch vehicle
stages
3.6
mating and unlocking device
device that connects the spacecraft and the launch vehicle together before separation and disconnects
the linkage between the spacecraft and the launch vehicle at the time of separation
3.7
separation impulse device
device that provides the energy to separate the spacecraft from the launch vehicle
3.8
separation system between launch vehicle and spacecraft
assembly of functionally related subsystems and/or units for the separation between launch vehicle
and spacecraft
3.9
test article
spacecraft, subsystem or unit on which a test is conducted
Note 1 to entry: For this document the definition is extended to address also launch vehicle system, subsystem or
unit.
3.10
separation test unit
assembly of test articles which undergoes separation test
4 Symbols and abbreviated terms
CoG centre of gravity
LV launch vehicle
SC spacecraft
SDOF single degree of freedom
SRS shock response spectrum
ζ damping ratio
5 General requirements
5.1 Purposes of separation testing
5.1.1 General
The separation testing is conducted for two types of purposes, which are verification purposes and
diagnostic purposes. A verification purpose is to verify conformity of characteristics of a separation
system between the LV and the SC (or between stages of a prototype LV model) with the specified
requirements. A diagnostic purpose is testing for physical system or operational design analysis.
5.1.2 Verification purposes
Verification purposes typically include:
a) to verify the functionality and characteristics of the separation system design and compatibility of
interfaces, including mechanical and electrical interfaces (e.g. fit check), between the LV and the SC,
as specified in ISO 14303:2002, Clauses 4 and 5;
b) to measure the parameters of separation relative movement, such as separation velocity,
acceleration, angular motion, separation displacement;
c) to measure the separation clearances between the separating hardware;
d) to measure the separation characteristic action timing during the separation process, such as time
to commence, time to clear.
5.1.3 Diagnostic purposes
Diagnostic purposes typically include:
a) to check and revise the separation analysis computational model and basic assumptions used in
the separation analysis;
b) to measure the shock levels on the points that are relevant to the launch vehicle side or to the
spacecraft side, and to check if the spacecraft is able to withstand the shock environment;
c) to test the separation function of the device (e.g. mating and unlocking device) designed for
separation of structural elements;
d) to test the distancing function provided by the separation impulse device;
e) to test purposes demanded by the test requirements, such as flexible-body distortion loads, which
are relevant to the launch vehicle side or to the spacecraft side during the separation process.
5.1.4 Tailoring guide
The purposes of separation testing in 5.1.2 and 5.1.3 may be tailored as the separation purposes can be
different for different projects or for different development stages.
5.2 General separation test process
5.2.1 General
The general separation test process flow is shown in Figure 1. The test process typically includes:
a) test documentation preparation and pre-test simulation;
b) test implementation;
c) test result data collection;
d) development and issuing of a test results assessment report.
5.2.2 Test documentation preparation and pre-test simulation
The test documents, which include documents of test plan, test specification, test procedure as defined
in ISO 15864:2021, 4.9, shall be prepared.
The test requirements for test articles, test facilities, test installation, preliminary adjustment of test
setup, measurement and data acquisition, as required in a separation test, shall be defined in the test
specification documents.
The documents of test specification and test procedure should be reviewed by the relevant sides to
make sure the documents conform to the test requirements. The test documentation review in the test
process flow shall be in line with the requirements of ISO 22137.
Pre-test simulation, which is specified in 5.6, shall meet the requirements of the test specification
documents and support the making of the test procedure documentation.
5.2.3 Test implementation
Test implementation typically includes the following procedures: test preparation, test execution,
follow-up activities after test, as illustrated in Annex E for a separation test.
5.2.4 Test results data collection
The test results data collection shall meet both the test data requirements, which are specified in 5.4,
and the measurement and data acquisition requirements, which are specified in Clause 9.
5.2.5 Test results evaluation
The test results shall be evaluated to assess whether the test results meet the test objectives as
specified in 5.9.
If the test results meet the test objectives, the test process may step into "Issue the test report
documentation" and end of the test process as shown in Figure 1.
If the test results do not meet the test objectives, a selection can be made between three ways to react
corresponding to the failures as shown in Figure 1.
a) If the failure is due to systems or interfaces design problems, the test should move to the step of
“redesign of the relevant systems or interfaces between the LV and SC”, then move to the step of
“test plan”, and proceed with the whole test process.
b) If the failure is due to test procedure problems, the test should move to the step of “test procedure
documentation review” to figure out whether the test procedure documentation meet the test
requirements given in the test specification documentation, then move to next step as shown in
Figure 1.
c) If the failure is due to test specification problems, the test should move to the step of “test
specification review” to figure out whether the test specification documentation meet the test
requirements given in the test plan documentation, then move to next step as shown in Figure 1.
Figure 1 — General separation test process
5.3 Test articles under separation test
5.3.1 Specification of separation test unit
5.3.1.1 Acceptance test
The separation test unit for an acceptance test comprises the following test articles: a flight model or
proto-flight model of a separation system between launch vehicle and spacecraft, a flight model or
proto-flight model of a certain part of a spacecraft and a flight model or proto-flight model of a certain
part of a launch vehicle.
5.3.1.2 Development test
In a development test between the SC and the LV, the separation test unit comprises the following test
articles: a prototype model of a separation system between launch vehicle and spacecraft, a mock-up of
a certain part of spacecraft and a mock-up of a certain part of a launch vehicle.
In a development test between stages of a prototype LV model, the separation test unit comprises the
following test articles: the mock-ups of two connecting launch vehicle stages and a prototype model of
the corresponding launch vehicle stages separation system.
5.3.2 Requirements for test articles
5.3.2.1 Technical characteristics
Technical characteristics of the test articles shall conform to the test specification documentation.
5.3.2.2 Interfaces
The mechanical and electrical interfaces at the separation surfaces of the test articles shall be identical
to those of the prototype model or the flight model, depending on different test purposes as defined in
5.3.1.
5.3.2.3 Substitutes
Some parts of test articles may be substituted by the mock-up parts when these mock-up parts do not
interfere with the purposes of the separation test.
5.3.2.4 Mass and stiffness
The mass and stiffness characteristics of the separation parts of test articles shall be identical to those
of the prototype model or the flight model, depending on different test purposes, when measuring the
separation motion parameters of the test.
5.3.2.5 Specification of difference between the SC/LV mock-up model and the flight model
The SC/LV mock-up model should be the structurally and/or physically similar items presenting a
simplified reproduction of a test object of SC/LV or its part intended for test.
The SC/LV flight model or proto-flight model is dedicated to be launched and operated in orbit and
should be subjected to acceptance testing.
While it is not always feasible to conduct full-scale mock-up tests, a reduced mock-up may be used in
the separation test where relevant technical characteristics of the reduced mock-up model should be
designed to be identical to those of the prototype model or the flight model.
5.3.2.6 Markings
There shall be obvious marks on the test articles for the high-speed video shooting.
5.3.3 Technical safety requirements for test articles
5.3.3.1 Confirmation
The test article’s technical safety status shall be confirmed before test.
5.3.3.2 Handling
The operators shall follow the relevant technical safety rules under the consideration of the
requirements of ISO 14620-1:2018, 8.3 in planning and executing the handling of the test articles, such
as hoisting, placement, transporting, installation.
5.3.3.3 Grounding
The test articles shall be electrically grounded. IEC 62305-3 provides information on the ground
resistance.
5.3.3.4 Safety protection
There shall be safety protection measures to protect the test articles from damaging both during and
after the process of the test.
5.4 Data requirements
5.4.1 Test data
Depending on the purpose of the test campaign, separation movement data and/or separation shock
response data, and/or the dedicated data by test requirements, shall be acquired.
5.4.2 Separation movement data
Separation movement data shall include translational acceleration, separation velocity, separation
displacement, angular velocity, attitude angle of the LV test articles and the SC test articles.
Separation movement data may be measured directly or obtained by processing the measured data.
5.4.3 Separation shock response data
Separation shock response data shall include shock acceleration time history data and shock response
spectrum data.
5.4.4 The dedicated data by test requirements
The dedicated data to be acquired, such as flexible-body distortion loads, shall be specified by the test
requirements, as the data can be different for different types of separation test.
5.5 Test timing and sequence
Timing and sequence shall be synchronized for every system involved in the test. Synchronization
accuracy shall be suitable to meet the test requirements.
5.6 Requirements for pre-test simulation
5.6.1 Purposes of pre-test simulation
Pre-test simulation shall:
a) evaluate kinematics of the test articles before the separation test;
b) determine the parameters of separation movement sensors, such as the measurements ranges,
accuracy. and the placement of the separation movement sensors;
c) determine the installation positions of high-speed cameras to get the most appropriate shooting
angle of field of view;
d) determine the placement of test articles capture systems to secure the safe recovery of the test
articles;
e) validate the analytical method and basic assumptions used in the separation by cross checking
the results between ground tests and simulation; the validated method is then used to verify that
requirements are met under worst-case flight conditions.
5.6.2 Requirements for the simulation modelling
5.6.2.1 Computational model
The computational model shall allow effective and reasonable simulation of the whole separation
process under consideration of the test requirements.
5.6.2.2 Coordinate systems
The coordinate systems for separation pre-test simulation shall be defined to be advantageous to
express the separation motion model in the simulation.
5.6.2.3 Sloshing/flexibility effect
The sloshing effect or the flexibility effect of the test articles during the separation process shall be
evaluated before the modelling of the test articles to decide if the sloshing effect or the flexibility effect
shall be included in the modelling.
5.6.2.4 Timing and sequence
The separation timing and sequence shall be set to duplicate the separation timing and sequence of the
separation test.
5.6.2.5 Initial conditions
The initial conditions shall be set to duplicate the initial conditions of the separation test.
5.6.2.6 Boundary conditions
As far as possible, the main boundary conditions modelling (e.g. constraint, contact) shall duplicate the
separation test boundary conditions.
5.6.2.7 Mass characteristics
The main mass characteristics (e.g. mass, CoG location, moment of inertia) of the test articles models
shall be set to duplicate the main mass characteristics of the physical test articles as far as possible.
5.6.2.8 Geometrical characteristics
The main geometry characteristics of the models shall conform to the main geometry characteristics
of the real test articles in the scenario of measuring the separation clearances between the separating
models or in other proper scenarios.
5.6.2.9 Separation impulse
As far as possible, the modelling of separation impulses shall duplicate the separation impulses in the
separation test.
5.6.3 Requirements for the simulation solver
The settings of optional parameters for the simulation solver, such as integrator type, simulation time
length, integral step size, integral accuracy, shall meet the simulation requirements.
5.6.4 Requirements for the simulation results
The simulation results shall include:
a) attitude angle of separation articles over time during the separation process;
b) attitude angular velocity of separation articles over time during the separation process;
c) critical clearance between separation articles over time during the separation process;
d) relative distance between separation articles over time during the separation process;
e) relative velocity between separation articles over time during the separation process.
The requirements for the simulation results may be tailored as the separation test purposes can be
different for different projects or for different development stages.
5.6.5 Validation of the simulation results
The validation of the simulation results shall include:
a) comparison of the results between separation test and the simulation method;
b) comparison of the results between different simulation methods.
5.7 Requirements for test environment
The test environment shall be specified in line with requirements of the test, usually including
temperature, atmosphere pressure, relative humidity, cleanliness and other requirements.
5.8 Exception handling
5.8.1 Test interruption
If any of the following situations appears, the test shall be interrupted:
a) test equipment failure;
b) the technical requirements are not met;
c) test articles failure.
5.8.2 Interruption handling
The requirements for retest in ISO 15864:2021, 4.8 shall be considered for the interruption handling.
5.9 Test results assessment
There shall be an assessment for the completeness, validity and correctness of test execution, test
results and data measured during the separation test with respect to the test objectives.
5.10 Test documentation
As defined in ISO 15864:2021, 4.9, the test documentation shall include a test plan, a test specification,
test procedures, test data, a test report and test logs
The test documentation may be tailored to fulfil the objectives of test.
6 Test facilities
6.1 General
Test facilities typically include control instrumentation, measurement instrumentation and equipment
and testing fixture.
6.2 Calibration requirements
Control and measurement instrumentation as specified in 6.3 and 6.4 shall be calibrated periodically
under consideration of ISO 15864:2021, 4.10.3.
6.3 Control instrumentation requirements
The main function of control instrumentation and equipment is, in line with the test timing, to
send release instructions (e.g. pyrotechnic devices ignition instructions) to the hold-down/release
mechanism controller to start the separation movement. Control instrumentation and equipment
typically include: electrical power source, hold-down/release mechanism controller (e.g. pyrotechnic
devices ignition controller) and connection cables.
6.3.1 Requirements for electrical power source
The output power, electric current and voltage of the electrical source shall conform to the test
requirements.
6.3.2 Requirements for hold-down/release mechanism controller and connection cables
6.3.2.1 Function
The hold-down/release mechanism controller shall allow hold-down/release mechanism timing
controlling.
6.3.2.2 Resolution
The timing resolution for the hold-down/release mechanism controller shall meet the test requirements
and shall be indicated.
6.3.2.3
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