Space engineering - European Cooperation for Space Standardization

Space engineering - European Cooperation for Space Standardization
ECSS-E-ST-20-07C
31 July 2008
Space engineering
Electromagnetic compatibility
ECSS Secretariat
ESA-ESTEC
Requirements & Standards Division
Noordwijk, The Netherlands
ECSS‐E‐ST‐20‐07C 31 July 2008 Foreword
This Standard is one of the series of ECSS Standards intended to be applied together for the management, engineering and product assurance in space projects and applications. ECSS is a cooperative effort of the European Space Agency, national space agencies and European industry associations for the purpose of developing and maintaining common standards. Requirements in this Standard are defined in terms of what shall be accomplished, rather than in terms of how to organize 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. This Standard has been prepared by the ECSS‐E‐ST‐20‐07 Working Group, reviewed by the ECSS Executive Secretariat and approved by the ECSS Technical Authority. Disclaimer
ECSS does not provide any warranty whatsoever, whether expressed, implied, or statutory, including, but not limited to, any warranty of merchantability or fitness for a particular purpose or any warranty that the contents of the item are error‐free. In no respect shall ECSS incur any liability for any damages, including, but not limited to, direct, indirect, special, or consequential damages arising out of, resulting from, or in any way connected to the use of this Standard, whether or not based upon warranty, business agreement , tort, or otherwise; whether or not injury was sustained by persons or property or otherwise; and whether or not loss was sustained from, or arose out of, the results of, the item, or any services that may be provided by ECSS. Published by: Copyright:
ESA Requirements and Standards Division ESTEC, P.O. Box 299,
2200 AG Noordwijk
The Netherlands
2008 © by the European Space Agency for the members of ECSS 2 ECSS‐E‐ST‐20‐07C 31 July 2008 Change log
ECSS‐E‐ST‐20‐07A Never issued ECSS‐E‐ST‐20‐07B Never issued ECSS‐E‐ST‐20‐07C First issue 31 July 2008 3 ECSS‐E‐ST‐20‐07C 31 July 2008 Table of contents
Change log .................................................................................................................3
Introduction................................................................................................................8
1 Scope.......................................................................................................................9
2 Normative references ...........................................................................................10
3 Terms, definitions and abbreviated terms..........................................................11
3.1
Terms from other standards ..................................................................................... 11
3.2
Terms specific to the present standard .................................................................... 12
3.3
Abbreviated terms .................................................................................................... 14
4 Requirements........................................................................................................16
4.1
General system requirements .................................................................................. 16
4.2
Detailed system requirements .................................................................................. 16
4.2.1
Overview..................................................................................................... 16
4.2.2
EMC with the launch system ...................................................................... 16
4.2.3
Lightning environment ................................................................................ 17
4.2.4
Spacecraft charging and effects ................................................................. 17
4.2.5
Spacecraft DC magnetic emission ............................................................. 18
4.2.6
Radiofrequency compatibility...................................................................... 19
4.2.7
Hazards of electromagnetic radiation ......................................................... 19
4.2.8
Intrasystem EMC ........................................................................................ 19
4.2.9
EMC with ground equipment ...................................................................... 20
4.2.10
Grounding................................................................................................... 20
4.2.11
Electrical bonding requirements ................................................................. 21
4.2.12
Shielding (excepted wires and cables) ....................................................... 22
4.2.13
Wiring (including wires and cables shielding)............................................. 22
5 Verification ............................................................................................................24
5.1
Overview .................................................................................................................. 24
5.1.1
Introduction................................................................................................. 24
5.1.2
Electromagnetic effects verification plan .................................................... 24
4 ECSS‐E‐ST‐20‐07C 31 July 2008 5.1.3
5.2
5.3
5.4
Electromagnetic effects verification report.................................................. 24
Test conditions ......................................................................................................... 24
5.2.1
Measurement tolerances ............................................................................ 24
5.2.2
Test site ...................................................................................................... 25
5.2.3
Ground plane.............................................................................................. 27
5.2.4
Power source impedance ........................................................................... 27
5.2.5
General test precautions ............................................................................ 29
5.2.6
EUT test configurations .............................................................................. 29
5.2.7
Operation of EUT........................................................................................ 32
5.2.8
Use of measurement equipment ................................................................ 33
5.2.9
Emission testing ......................................................................................... 34
5.2.10
Susceptibility testing ................................................................................... 36
5.2.11
Calibration of measuring equipment........................................................... 37
System level ............................................................................................................. 38
5.3.1
General....................................................................................................... 38
5.3.2
Safety margin demonstration for critical or EED circuits ............................ 38
5.3.3
EMC with the launch system ...................................................................... 38
5.3.4
Lightning ..................................................................................................... 39
5.3.5
Spacecraft and static charging ................................................................... 39
5.3.6
Spacecraft DC magnetic field emission...................................................... 39
5.3.7
Intra–system electromagnetic compatibility................................................ 39
5.3.8
Radiofrequency compatibility...................................................................... 39
5.3.9
Grounding................................................................................................... 40
5.3.10
Electrical bonding ....................................................................................... 40
5.3.11
Wiring and shielding ................................................................................... 40
Equipment and subsystem level test procedures ..................................................... 40
5.4.1
Overview..................................................................................................... 40
5.4.2
CE, power leads, differential mode, 30 Hz to 100 kHz ............................... 41
5.4.3
CE, power and signal leads, 100 kHz to 100 MHz ..................................... 43
5.4.4
CE, power leads, inrush current ................................................................. 46
5.4.5
DC Magnetic field emission, magnetic moment ......................................... 48
5.4.6
RE, electric field, 30 MHz to 18 GHz .......................................................... 51
5.4.7
CS, power leads, 30 Hz to 100 kHz........................................................... 55
5.4.8
CS, bulk cable injection, 50 kHz to 100 MHz.............................................. 57
5.4.9
CS, power leads, transients........................................................................ 61
5.4.10
RS, magnetic field, 30 Hz to 100 kHz......................................................... 64
5.4.11
RS, electric field, 30 MHz to 18 GHz .......................................................... 67
5 ECSS‐E‐ST‐20‐07C 31 July 2008 5.4.12
Susceptibility to electrostatic discharges .................................................... 73
Annex A (informative) Subsystem and equipment limits.....................................78
A.1
Overview .................................................................................................................. 78
A.2
CE on power leads, differential mode, 30 Hz to 100 MHz........................................ 78
A.3
CE on power leads, in-rush currents ........................................................................ 80
A.4
CE on power and signal leads, common mode, 100 kHz to 100 MHz ..................... 80
A.5
CE on antenna ports ................................................................................................ 81
A.6
DC magnetic field emission ...................................................................................... 81
A.6.1
General....................................................................................................... 81
A.6.2
Characterization ......................................................................................... 81
A.6.3
Limit ............................................................................................................ 82
A.7
RE, low-frequency magnetic field............................................................................. 83
A.8
RE, low-frequency electric field ................................................................................ 83
A.9
RE, electric field, 30 MHz to 18 GHz ........................................................................ 83
A.10 CS, power leads, differential mode, 30 Hz to 100 kHz. ............................................ 84
A.11 CS, power and signal leads, common mode, 50 kHz to 100 MHz ........................... 85
A.12 CS, power leads, short spike transients ................................................................... 85
A.13 RS, magnetic field, 30 Hz to 100 kHz....................................................................... 86
A.14 RS, electric field, 30 MHz to 18 GHz ........................................................................ 87
A.15 Susceptibility to electrostatic discharge.................................................................... 88
Figures
Figure 4-1: Bonding requirements.......................................................................................... 22
Figure 5-1: RF absorber loading diagram .............................................................................. 26
Figure 5-2: Line impedance stabilization network schematic ................................................. 28
Figure 5-3: General test setup................................................................................................ 30
Figure 5-4: Typical calibration fixture ..................................................................................... 34
Figure 5-5: Conducted emission, 30 Hz to 100 kHz, measurement system check ................ 43
Figure 5-6: Conducted emission, 30 Hz to 100 kHz, measurement setup ............................. 43
Figure 5-7: Conducted emission, measurement system check.............................................. 44
Figure 5-8: Conducted emission, measurement setup in differential mode ........................... 44
Figure 5-9: Conducted emission, measurement setup in common mode .............................. 45
Figure 5-10: Inrush current: measurement system check setup ............................................ 47
Figure 5-11: Inrush current: measurement setup ................................................................... 47
Figure 5-12: Smooth deperm procedure ................................................................................ 51
Figure 5-13: Electric field radiated emission. Basic test setup ............................................... 53
Figure 5-14: Electric field radiated emission. Antenna positioning......................................... 53
6 ECSS‐E‐ST‐20‐07C 31 July 2008 Figure 5-15: Electric field radiated emission. Multiple antenna positions ............................... 54
Figure 5-16: CS, power leads, measurement system check set-up....................................... 56
Figure 5-17: CS, power leads, signal injection ....................................................................... 56
Figure 5-18: Bulk cable injection, measurement system check set-up .................................. 60
Figure 5-19: Signal test waveform.......................................................................................... 60
Figure 5-20: CS of power and signal leads, bulk cable injection............................................ 60
Figure 5-21: CS of power leads, transients, calibration set-up............................................... 62
Figure 5-22: CS of power leads, spike series injection test setup.......................................... 62
Figure 5-23: CS of power leads, spike parallel injection test setup........................................ 63
Figure 5-24: Measurement system check configuration of the radiating system ................... 65
Figure 5-25: Basic test set-up ................................................................................................ 65
Figure 5-26: Test equipment configuration............................................................................. 69
Figure 5-27: RS Electric field. Multiple test antenna positions ............................................... 70
Figure 5-28: Receive antenna procedure............................................................................... 70
Figure 5-29: Spacecraft charging ESD susceptibility test ...................................................... 75
Figure 5-30: Susceptibility to ESD: calibration configuration.................................................. 76
Figure 5-31: Susceptibility to ESD: test equipment configuration .......................................... 76
Figure A-1 : Power leads, conducted emission ...................................................................... 79
Figure A-2 : Common mode conducted emission .................................................................. 79
Figure A-3 : Radiated electric field limit.................................................................................. 80
Figure A-4 : Conducted susceptibility limit, frequency domain............................................... 84
Figure A-5 : CS, voltage spike in percentage of test bus voltage........................................... 86
Figure A-6 : Radiated susceptibility limit ................................................................................ 87
Tables
Table 5-1: Absorption at normal incidence............................................................................. 26
Table 5-2: Bandwidth and measurement time........................................................................ 35
Table 5-3: Correspondence between test procedures and limits ........................................... 41
Table A-1 : Equipment: susceptibility to conducted interference, test signal ......................... 85
7 ECSS‐E‐ST‐20‐07C 31 July 2008 Introduction
Electromagnetic compatibility (EMC) of a space system or equipment is the ability to function satisfactorily in its electromagnetic environment without introducing intolerable electromagnetic disturbances to anything in that environment. The space system is designed to be compatible with its external natural, induced, or man‐made electromagnetic environment. Natural components are lightning for launchers, the terrestrial magnetic field for space vehicles. Spacecraft charging is defined as voltage building‐up of a space vehicle or spacecraft units when immerged in plasma. Electrostatic discharges result from spacecraft charging with possible detrimental effects. External man‐made interference, intentional or not, are caused by radar or telecommunication beams during ground operations and the launching sequence. Intersystem EMC also applies between the launcher and its payload or between space vehicles. Intrasystem EMC is defined between all electrical, electronic, electromagnetic, and electromechanical equipment within the space vehicle and by the presence of its self‐induced electromagnetic environment. It comprises the intentional radiated electromagnetic fields and parasitic emission from on‐board equipment. Both conducted and radiated emissions are concerned. An electromagnetic interference safety margin is defined at system critical points by comparison of noise level and susceptibility at these points. 8 ECSS‐E‐ST‐20‐07C 31 July 2008 1
Scope
EMC policy and general system requirements are specified in ECSS‐E‐ST‐20. This ECSS‐E‐ST‐20‐07 Standard addresses detailed system requirements (Clause 4), general test conditions, verification requirements at system level, and test methods at subsystem and equipment level (Clause 5) as well as informative limits (Annex A). Associated to this standard is ECSS‐E‐ST‐20‐06 “Spacecraft charging”, which addresses charging control and risks arising from environmental and vehicle‐
induced spacecraft charging when ECSS‐E‐ST‐20‐07 addresses electromagnetic effects of electrostatic discharges. Annexes A to C of ECSS‐E‐ST‐20 document EMC activities related to ECSS‐E‐ST‐20‐07: the EMC Control Plan (Annex A) defines the approach, methods, procedures, resources, and organization, the Electromagnetic Effects Verification Plan (Annex B) defines and specifies the verification processes, analyses and tests, and the Electromagnetic Effects Verification Report (Annex C) document verification results. The EMEVP and the EMEVR are the vehicles for tailoring this standard. This standard may be tailored for the specific characteristic and constrains of a space project in conformance with ECSS‐S‐ST‐00. 9 ECSS‐E‐ST‐20‐07C 31 July 2008 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 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. ECSS‐S‐ST‐00‐01 ECSS system ‐ Glossary of terms ECSS‐E‐ST‐20 Space engineering ‐ Electrical and electronic ECSS‐E‐ST‐20‐06 Space engineering ‐ Spacecraft charging ECSS‐E‐ST‐33‐11 Space engineering ‐ Explosive systems and devices ECSS‐E‐ST‐50‐14 Space engineering – Spacecraft discrete interfaces IEC 61000‐4‐2 (Edition 1.2) Electromagnetic compatibility (EMC) ‐ Part 4‐2: Testing and measurement techniques ‐ Electrostatic discharge immunity test 10 ECSS‐E‐ST‐20‐07C 31 July 2008 3
Terms, definitions and abbreviated terms
3.1
Terms from other standards
For the purpose of this Standard, the terms and definitions from ECSS‐S‐ST‐00‐01 apply, in particular for the following terms: critical item customer equipment item launcher, launch vehicle mission requirement safety critical function supplier spacecraft, space vehicle subsystem system test verification For the purposes of this Standard, the following terms have a specific definition contained in ECSS‐E‐ST‐20: conducted emission electromagnetic compatibility electromagnetic compatibility control electromagnetic interference electromagnetic interference safety margin emission high‐voltage lightning indirect effects 11 ECSS‐E‐ST‐20‐07C 31 July 2008 radiated emission radiofrequency susceptibility susceptibility threshold For the purposes of this document, the following terms have a specific definition contained in ECSS‐E‐ST‐20‐06: electrostatic discharge (ESD) secondary arc For the purposes of this document, the following term has a specific definition contained in ECSS‐E‐ST‐33‐11: electro‐explosive device (EED) 3.2
Terms specific to the present standard
3.2.1
ambient level
level of radiated and conducted signal, and noise that exist at the specified test location and time when the equipment under test is not operating NOTE 3.2.2
E.g. atmospherics, interference from other sources, and circuit noise or other interference generated within the measuring set compose the “ambient level”. antenna factor
factor that, when properly applied to the voltage at the input terminals of the measuring instrument, yields the electric or magnetic field strength NOTE 1 This factor includes the effects of antenna effective length, mismatch, and transmission losses. NOTE 2 The electric field strength is normally expressed in V/m and the magnetic field strength in A/m or T. 3.2.3
common mode voltage
voltage difference between source and receiver ground references 3.2.4
contact discharge method
method of testing in which the electrode of the high‐voltage test generator is held in contact with the discharge circuit, and the discharge actuated by a discharge switch 12 ECSS‐E‐ST‐20‐07C 31 July 2008 3.2.5
electromagnetic environmental effects
impact of the electromagnetic environment upon equipment, systems, and platforms NOTE 3.2.6
It encompasses all electromagnetic disciplines, including electromagnetic compatibility; electromagnetic interference, electromagnetic vulnerability, hazards of electromagnetic radiation to personnel, electro‐explosive devices, volatile materials, and natural phenomena effects. field strength
resultant of the radiation, induction and quasi‐static components of the electric or magnetic field NOTE 3.2.7
The term “electric field strength” or “magnetic field strength” is used, according to whether the resultant, electric or magnetic field, respectively, is measured. ground plane
metal sheet or plate used as a common reference point for circuit returns and electrical or signal potentials 3.2.8
improper response
subsystem or equipment response which can be either inadvertent or unacceptable 3.2.9
inadvertent response
proper subsystem functional response (within normal range of limits) actuated by electromagnetic interference, but occurring at other than the normal operational cycle, which in turn causes improper response to the total space system 3.2.10
line impedance stabilization network (LISN)
network inserted in the supply leads of an apparatus to be tested which provides, in a given frequency range, a specified source impedance for the measurement of disturbance currents and voltages and which can isolate the apparatus from the supply mains in that frequency range 3.2.11
not operating
condition wherein no power is applied to the equipment 3.2.12
overshield
shield surrounding a bundle or a shielded cable 3.2.13
passive intermodulation product
generation of a signal at frequency f = n*f1 + m*f2 from two signals at frequencies f1 and f2, where n and m are positive or negative integers, by a passive device, usually an electrical contact 13 ECSS‐E‐ST‐20‐07C 31 July 2008 3.2.14
port
place of access to a device or network where energy can be supplied or withdrawn, or where the device or network variables can be observed or measured 3.2.15
power quality requirements
requirements which define the conducted voltage noise or impedance the power user can expect NOTE 3.2.16
Noise e.g. from load regulation, spikes, and sags. soft magnetic material
ferromagnetic material with a coercivity smaller than 100 A/m 3.2.17
spurious emission
electromagnetic emission from the intended output terminal of an electronic device, but outside of the designed emission bandwidth 3.2.18
test antenna
antenna of specified characteristics designated for use under specified conditions in conducting tests 3.2.19
unit
equipment that is viewed as an entity for purposes of analysis, manufacturing, maintenance, or record keeping NOTE 3.3
E.g. hydraulic actuators, valves, batteries, and individual electronic boxes such as on‐board computer, inertial measurement unit, reaction wheel, star tracker, power conditioning unit, transmitters, receivers, or multiplexers. Abbreviated terms
For the purpose of this standard, the abbreviated terms of ECSS‐S‐ST‐00‐01 and the following apply: Abbreviation Meaning AC alternating current ACS attitude control system AM amplitude modulation AWG American wire gauge BCI bulk cable injection CE conducted emission CS conducted susceptibility CW continuous wave DC direct current 14 ECSS‐E‐ST‐20‐07C 31 July 2008 EED electro‐explosive device EGSE electrical ground support equipment EHF extremely high frequency (30 GHz‐300 GHz) EMC electromagnetic compatibility EMCAB electromagnetic compatibility advisory board EMCCP electromagnetic compatibility control plan EMEVP electromagnetic effects verification plan EMEVR electromagnetic effects verification report EMI electromagnetic interference EMISM electromagnetic interference safety margin ESD electrostatic discharge EUT equipment under test HV high voltage ICD interface control document LEO low Earth orbit LF low frequency LISN line impedance stabilization network MGSE mechanical ground support equipment PAM pulse amplitude modulation PCM pulse coded modulation RE radiated emission RF radio frequency r.m.s. root‐mean‐square RS radiated susceptibility SHF super‐high frequency (3 GHz‐30 GHz) 15 ECSS‐E‐ST‐20‐07C 31 July 2008 4
Requirements
4.1
General system requirements
EMC policy and general system requirements, and the spacecraft charging protection program are specified in ECSS‐E‐ST‐20 Electromagnetic Compatibility clause and EMC Plan DRD. 4.2
Detailed system requirements
4.2.1
Overview
This clause 4.2 defines the requirements for design and realization at system level. They are the basis for definition of activities of the EMC programme to ensure space‐system‐level compatibility with minimum impact to programme, cost, schedule, and operational capabilities. 4.2.2
EMC with the launch system
4.2.2.1
Overview
General system requirements for “EMC with the launch system” are defined in ECSS‐E‐ST‐20. 4.2.2.2
a.
Detailed system requirements
Overload capability of the spacecraft RF receivers during the pre‐launch and launch phases with or without fairing, shall be demonstrated by the spacecraft supplier. NOTE 1 It is expected the electromagnetic environment generated by companion payloads is assessed by the launching company and addressed in the User’s Manual. NOTE 2 A conductive fairing is likely to cause resonances and cavity effects. b.
Spacecraft equipment shall not exhibit any malfunction, degradation of performance or deviation beyond the tolerance indicated in its individual 16 ECSS‐E‐ST‐20‐07C 31 July 2008 specification after being exposed, even not operating, to the electromagnetic environment from the launcher and launch site. NOTE c.
Most of spacecraft equipment is not operating during launch. During the launching sequence spacecraft transmitters and receivers (platform and payload) can be either in OFF‐ or ON‐state depending on the launch vehicle. The electromagnetic interference safety margin (EMISM) of safety critical equipment shall be applied to equipment in ON‐state during prelaunch and launch phase and to EED’s. 4.2.3
Lightning environment
4.2.3.1
Overview
Protection of the space system against both direct and indirect effects of lightning can be a combination of operational avoidance of the lightning environment and electrical overstress design techniques. 4.2.3.2
Requirements to the space system
a.
Assessment of risk, on the launch pad inside the protected area, for the space system and its equipment against direct and indirect effects of lightning before lift‐off, shall be performed. b.
The spacecraft supplier shall obtain from the launching company the electromagnetic environment imposed on the launcher payloads in case of lightning. 4.2.4
Spacecraft charging and effects
4.2.4.1
Overview
Mitigation of risks related to spacecraft charging results of a combination of rules and methods preventing voltage build‐up and so minimizing the occurrence of ESD, and techniques for controlling EMI from residual ESD. ECSS‐E‐ST‐20 addresses management of spacecraft charging protection and system‐level performance under effects of spacecraft charging and related ESD or secondary arcs. ECSS‐E‐ST‐20‐06 addresses charging control and risks arising from spacecraft charging and other environmental effects on the spacecraft’s electrical behaviour. 17 ECSS‐E‐ST‐20‐07C 31 July 2008 4.2.4.2
a.
EMI control requirements to system and equipment
in relation with ESD
Analysis or tests at system level shall be performed for assessing the threat at subsystem or equipment level. NOTE Analysis or tests can be defined in the time or frequency domain. They are expected to evaluate the coupling level from the ESD source to critical points. b.
EMI control from residual ESD shall be performed by a combination of shielding and passive or active filtering techniques, implemented on the main structure, at subsystem level or inside equipment. c.
EMI control efficiency shall be verified by test at subsystem or equipment level. 4.2.5
Spacecraft DC magnetic emission
4.2.5.1
Spacecraft with susceptible payload
a.
As part of the EMCCP, a magnetic cleanliness control plan shall document: 1.
magnetic control guidelines 2.
emission limits to magnetic sources 3.
a magnetic budget 4.
specific test methods applied to equipments for emission measurement and characterization NOTE 4.2.5.2
a.
The test method described in 5.4.4.4 providing a dipole model can be inadequate and replaced by a multiple dipole model or a spherical harmonics model. Attitude control system (ACS)
As part of the EMCCP, a magnetic budget shall be maintained providing: 1.
Three‐axes components of the space vehicle magnetic dipole (component decreasing with the inverse cube law with distance). NOTE Typical values lie in the range 1 Am2 or less for small spacecraft to much more than 10 Am2 for large spacecraft. 2.
If the solar array is rotating in the space vehicle axes, separate evaluation for the main body and the solar array. 3.
When the space vehicle is using a magnetic sensor as part of the ACS, evaluation of the magnetic induction at its location. NOTE The angular deviation is the basic requirement; however, the requirement is generally expressed in 18 ECSS‐E‐ST‐20‐07C 31 July 2008 terms of modification of the natural field strength at the sensor location. For LEO spacecraft if the error on each axis is less than 1 μT, the modification of the direction is kept less than 20 milliradians. b.
The specified maximum magnetic field value shall comprise the remanent magnetization (magnets, electro‐magnets in off‐state, or residual perm‐up due to hysteresis of soft materials), the induced magnetization of soft materials by the geomagnetic field, and the momentum of current loops. 4.2.6
Radiofrequency compatibility
a.
Spurious emissions requirements at antenna ports shall be specified for RF compatibility purpose by the spacecraft supplier. b.
When specifying limits and frequency ranges, the following issues shall be included: 1.
sensitivity of possible victim receiver subsystems including out‐of‐
band response, 2.
no limits apply to transmit frequencies and information carrying modulation bandwidths, 3.
highest and lowest intentional frequency used by space system receivers, 4.
antenna port attachments, gain/loss characteristics. 4.2.7
Hazards of electromagnetic radiation
Assessment of hazards to electromagnetic radiation is a part of the process specified in ECSS‐Q‐ST‐40‐02 “Hazard analysis”, clause “Hazard analysis requirements”. 4.2.8
a.
Intrasystem EMC
Intrasystem EMC shall be achieved by: 1.
allocation of equipment‐level EMI requirements documented in the EMCCP, including: (a)
limits on conducted and radiated emission, (b)
susceptibility thresholds. NOTE b.
Recommended data is defined in Annex A for equipment and subsystems. control of conducted and radiated propagation paths methods defined by clauses 4.2.10 to 4.2.13. 19 ECSS‐E‐ST‐20‐07C 31 July 2008 4.2.9
a.
b.
EMC with ground equipment
The EGSE and MGSE used for spacecraft integration and ground testing shall: 1.
Not degrade the EMC performance of the spacecraft; 2.
Have no impact on grounding or isolation. The EGSE shall be immune to signals used for spacecraft susceptibility tests. 4.2.10
Grounding
4.2.10.1
Overview
As specified in ECSS‐E‐ST‐20, a controlled ground reference concept is defined for the space system. Structural elements, antenna and RF reference grounds, power and signal returns, shields and cable shields, safety grounds, EGSE grounds are considered. 4.2.10.2
Requirements
a.
A system‐level grounding diagram shall be established including the EGSE. b.
A ground reference shall be identified for each power, signal, or RF source or receiver. c.
An upper value of common mode voltage shall be specified considering: d.
1.
power quality requirements defined in ECSS‐E‐ST‐20 for “Spacecraft bus”, 2.
type of detectors and sensitivity, 3.
characteristics of analogue signal monitor receiver circuit, in accordance with ECSS‐E‐ST‐50‐14, Table 5‐2 d, 4.
characteristics of bi‐level signal monitor receiver circuit, in accordance with ECSS‐E‐ST‐50‐14, clause Table 6‐2 e, 5.
hazards due to fault currents internal to the space vehicle or between the space vehicle and its EGSE. When power and signal share common paths (wire or structure), the magnitude of ground impedance shall be limited over the affected signal spectrum. NOTE Non‐exclusive techniques for reducing the impedance are decrease of common path length, decrease of wire and ground impedance, filters on common paths. 20 ECSS‐E‐ST‐20‐07C 31 July 2008 4.2.11
Electrical bonding requirements
4.2.11.1
Overview
a.
Bonding requirements are a mean for fulfilling grounding requirements. NOTE 4.2.11.2
Bonding for charging control is specified in ECSS‐E‐ST‐20‐06 “Electrical continuity”, including surfaces and structural and mechanical parts. Normative provisions
a.
A vehicle bonding attachment point connected to the vehicle structure shall be provided as a ground reference point at system level. b.
An equipment bonding stud connected to the unit housing shall be provided as a ground reference at equipment level. c.
Each unit housing shall be bonded to the nearby spacecraft structure from the equipment bonding stud. d.
The DC resistance between the equipment bonding stud and the nearby spacecraft structure shall be less than 2,5 mΩ. e.
The inductance between the equipment bonding stud and the nearby spacecraft structure shall be less than 30 nH. NOTE Example of formula for bonding strap inductance calculation commonly used: L = 200 a [Loge(2a/b) + 0,5 + 0,22 b/a] L inductance in units of nH a: strap length in units of m b: width plus thickness of the strap in units of m f.
The DC resistance between the unit housing and the vehicle bonding attachment point shall be less than 20 mΩ. g.
The DC resistance between the unit housing and the vehicle bonding attachment point may be split as shown in Figure 4‐10. h.
Bonds shall be capable to carry the fault currents determined by analysis at system level, without fusing, burning, or arcing. i.
If the structure is used as the return current path, bonding provisions shall be such that DC and AC voltage drops along power paths comply with clause 4.2.10.2c. 4.2.11.3
a.
External grounds
The functionality of connecting grounding cables for charge equalization shall be provided on space systems. NOTE Charge equalization is needed prior to implementing other procedures or the application of power across the interface. 21 ECSS‐E‐ST‐20‐07C 31 July 2008 Connector Equipment housing <10 m Ω Equipment bonding stud <20 m Ω Vehicle‐bonding attachment point Ground reference point at system level Bonding strap
Nearby structure grounding Main frame Vehicle structure Figure 4‐1: Bonding requirements 4.2.12
Shielding (excepted wires and cables)
4.2.12.1
Overview
When shielding is used to control EMC with the environment, it can be provided by the basic space vehicle structure designed as a “Faraday cage”, by enclosures of electronics boxes, or by cable or bundle overshields. 4.2.12.2
a.
Requirement
Electronics units and cables external to the basic space vehicle structure shall have individual shields providing attenuation to EMI. NOTE It is important to consider apertures used for pressure drop during ascent and for outgassing. 4.2.13
Wiring (including wires and cables
shielding)
4.2.13.1
Classification of cables
a.
b.
Categorisation of harness and separate routings for wires of different categories shall be defined as follows: 1.
applicable to critical lines as defined in ECSS‐E‐ST‐20, Clause “Electromagnetic interference safety margin”. 2.
made on the basis of the characteristics of the signals on the wire (and hence the interference generated), and on the susceptibility of the circuit to EMI. Wires falling into one category shall be assembled into a same bundle. 22 ECSS‐E‐ST‐20‐07C 31 July 2008 c.
Bundles of different categories shall be separated either by a separation distance of 5 cm from the outer circumference or by a metallic screen when they are routed on parallel paths. NOTE d.
Overshields or spacecraft walls can be used to fulfil the requirement. Wires and cables shall be marked in such a manner that personnel can visually identify the EMC category for each wire or cable. 4.2.13.2
Cable shields
a.
Cable shields shall not be used as an intentional current carrying conductor, except coaxial cables in radiofrequency circuits and high‐
speed data links using coaxial cables. b.
Cable shields, other than overshields, shall have an insulated sheath to prevent uncontrolled grounding. c.
Connectors used to carry shielded wires shall d.
1.
not use a nonconductive finish, 2.
provide contact to the equipment housing with a resistance less than 10 mΩ through the equipment connector body as shown. Bonding of cable shields shall be as following: 1.
Bonding to chassis ground is performed at both ends: (a)
through the equipment connector body, (b)
using a backshell that provides for circumferential bonding of shields, or using a halo‐ring. NOTE 2.
Connection to electrical reference is performed through dedicated pins. NOTE e.
This case typically appears in the design of detection chains. Overshields shall be bonded to chassis ground: 1.
at both ends, 2.
using a 360° direct contact or a bond strap of less than 30 nH NOTE f.
No grounding inside the equipment through a connector ground pin in order to prevent any perturbation inside the equipment. See NOTE of clause 4.2.11.2e. Overshields should be bonded to chassis ground at intermediary points with a separation distance less than 1m between two grounding points. 23 ECSS‐E‐ST‐20‐07C 31 July 2008 5
Verification
5.1
Overview
5.1.1
Introduction
This Clause specifies general conditions for EMC testing, requirements for verification at system level and detailed procedures for unit and subsystem level testing. 5.1.2
Electromagnetic effects verification plan
The electromagnetic effects verification plan (EMEVP) provides the instruction for conducting all activities needed to verify electromagnetic effects requirements. This document defines the approach, methods, procedures, and specific test conditions. The content is specified in the EMEVP DRD of ECSS‐E‐ST‐20. The EMEVP is the vehicle for tailoring procedures and test conditions. 5.1.3
Electromagnetic effects verification report
The electromagnetic effects verification report (EMEVR) documents activities and report analysis or test results in relation with the verification of the electromagnetic effects. It is established based on the electromagnetic effects verification plan (EMEVP). The content of the EMEVR is defined in the EMEVR DRD of ECSS‐E‐ST‐20 supplemented by specific requirements defined hereafter in 5.3 and 5.4. 5.2
Test conditions
5.2.1
a.
Measurement tolerances
The tolerance for EMC testing shall be as follows: 1.
Distance: ±10 % 2.
Frequency: ±2 % 3.
Amplitude, measurement receiver: ±2 dB 24 ECSS‐E‐ST‐20‐07C 31 July 2008 4.
Amplitude, measurement system (includes receivers, transducers, cables, connectors): ±3 dB 5.
Time (waveforms): ±10 % 6.
Resistors: ±5 % 7.
Capacitors: ±20 % 5.2.2
Test site
5.2.2.1
Overview
measurement Shielded enclosures or unshielded sites are used for testing. Shielded enclosures prevent external environment signals from contaminating emission measurements and susceptibility test signals from interfering with electrical and electronic items near the test facility. In unshielded sites, the tests are performed during times and conditions when the electromagnetic ambient is at its lowest level. 5.2.2.2
Shielded enclosures
a.
The enclosures shall be large such that the EUT arrangement requirements of 5.2.6 and antenna positioning requirements described in the individual test procedures are satisfied. b.
RF absorber material shall be used when performing electric field radiated emissions or radiated susceptibility testing to reduce reflections of electromagnetic energy and to improve accuracy and repeatability. NOTE Example of RF absorber material are carbon impregnated foam pyramids, and ferrite tiles. c.
The RF absorber shall be placed above, behind, and on both sides of the EUT, and behind the radiating or receiving antenna as shown in Figure 5‐1. d.
Minimum performance of the material shall be as specified in Table 5‐1. NOTE The manufacturer’s specification of their RF absorber material (basic material only, not installed) can be used. 25 ECSS‐E‐ST‐20‐07C 31 July 2008 > 30 cm > 30 cm EUT
RF absorber placed above, behind and on both sides of EUT from ceiling to ground > 1 m
> 50 cm Test antenna
> 30 cm RF absorber placed behind the test antenna from ceiling to floor Figure 5‐1: RF absorber loading diagram Table 5‐1: Absorption at normal incidence Frequency Minimum absorption 80 MHz – 250 MHz 6 dB above 250 MHz 10 dB 5.2.2.3
Ambient electromagnetic level
a.
The ambient electromagnetic level shall be measured with the EUT not operating and all auxiliary equipment turned on. b.
During testing, at least one of the following conditions shall be met: c.
1.
the ambient is at least 6 dB below the individual test limits, 2.
the EUT complies with the individual test limits, 3.
it is shown that recorded data exceeding the limits cannot be generated by the EUT (emission tests) or cannot sensitize the EUT (susceptibility tests). Background plots shall be reported for each test configuration unless all recorded data is at least 6dB below the individual test limits. 5.2.2.4
a.
Ambient conducted level
Ambient conducted levels on power leads shall be measured with the leads disconnected from the EUT and connected to a resistive load that draws the same rated current as the EUT. 26 ECSS‐E‐ST‐20‐07C 31 July 2008 5.2.3
Ground plane
5.2.3.1
General
a.
If the actual installation is known, the EUT shall be installed on a ground plane that simulates the actual installation. b.
If the actual installation is unknown or multiple installations are expected, then the EUT shall be installed on a metallic ground plane. c.
Ground planes shall be 2 m² or larger in area with the smaller side no less than 75 cm. d.
When a ground plane is not present in the actual EUT installation, the EUT shall be placed on a non‐conductive table. NOTE 5.2.3.2
In such a case, test methods are specific and are likely to differ from the ones in the present standard. Metallic ground plane
a.
When the EUT is installed on a metallic ground plane, the ground plane shall have a DC surface resistance not larger than 0,1 mΩ per square. b.
The DC resistance between metallic ground planes and the shielded enclosure shall be 2,5 mΩ or less. c.
The metallic ground planes shall be electrically bonded to the floor or wall of the basic shielded room structure at least once every 1 m. d.
The metallic bond straps shall be solid and maintain a five‐to‐one ratio or less in length to width. e.
Metallic ground planes used outside a shielded enclosure shall extend at least 1,5 m beyond the test setup boundary in each direction. 5.2.3.3
Composite ground plane
a.
When the EUT is installed on a conductive composite ground plane, the surface resistivity of the actual installation shall be used. b.
Composite ground planes shall be electrically bonded to the enclosure with means suitable to the material. 5.2.4
Power source impedance
a.
The impedance of power sources providing input power to the EUT shall be controlled by Line Impedance Stabilization Networks (LISN’s) for all measurement. b.
LISNʹs shall not be used on output power leads. c.
The LISNʹs shall be located at the power source end of the exposed length of power leads specified in 5.2.6.6. d.
The LISN circuit shown in Figure 5‐2 shall be used. 27 ECSS‐E‐ST‐20‐07C 31 July 2008 NOTE 1 The LISN can be split in several cases, one per power lead. NOTE 2 The series inductances represent the inductances of the wiring; the series resistances represent the resistances of the wiring and of the central protections. NOTE 3 The 50 Ω resistors result in 100 Ω at high frequency, similar to the characteristic impedance of the line. NOTE 4 The feed‐through capacitors provide a short‐circuit at high frequency and make the LISN symmetrical NOTE 5 Connecting the regulation wires of the laboratory supply at the LISN input in order to provide sufficiently low impedance at low frequency is an appropriate method. The source impedance is then dominated by the series resistances in the LISN. Alternatively, a large capacitor (between 1 mF and 10 mF) will be used. To Power
Source
470nF
to 10µF
+
x μH
50 Ω
Regulation wires
─
y mΩ
100 kΩ
Optional
1 to 10mF
x μH
Metal
enclosure
+
To EUT
y mΩ
─
50 Ω
Bonding stud
470nF 100 kΩ
to 10µF
Figure 5‐2: Line impedance stabilization network schematic e.
If no value is specified x = 2 μH and y = 0,1 Ω shall be used. NOTE The x and y values, respectively the inductance and the resistance inserted in each lead are expected in the EMEVP. f.
Magnetic coupling between inductors shall be avoided. g.
If the return line is grounded at the power source in the actual installation (star distribution), the return line of the LISN shall be grounded on the power source side. h.
If the return line(s) of the actual installation is locally grounded (chassis return), the return line of the LISN need not be provided, and the tests shall be performed with the return(s) tied to case. 28 ECSS‐E‐ST‐20‐07C 31 July 2008 i.
The LISN impedance shall be measured at least annually under the following conditions: 1.
the impedance, measured between the power output lead on the EUT side of the LISN and the metal enclosure of the LISN, 2.
an unterminated power input terminal on the power source side of the LISN. 5.2.5
General test precautions
5.2.5.1
Safety
a.
Clause 4.2.7 shall apply for tests involving high electromagnetic power or high voltage test equipment. 5.2.5.2
a.
Only the equipment and the personnel used to perform the test shall be present in the test area or enclosure. 5.2.5.3
a.
Excess personnel and equipment
Overload precautions
Checks shall be performed to assure that an overload condition does not exist. NOTE b.
Measurement receivers and transducers are subject to overload, especially receivers without preselectors and active transducers. Overload condition shall be corrected. NOTE This can be done by instrumentation changes. 5.2.6
EUT test configurations
5.2.6.1
General
a.
The EUT shall be configured as shown in the general test setup of Figure 5‐3 and maintained during all testing. NOTE For radiated tests, it may be desirable to have the LISN outside of the shielded room. 29 ECSS‐E‐ST‐20‐07C 31 July 2008 4
7
1: EUT
2: LISN
3: Power source
4: Access panel
5: Interconnecting cable
6: Power lead
7: Bonding strap
8: Non-conductive standoff
9: Grounding plane
3
7
7
7
1
1
5
7
2
5cm
9
10cm
6
8
2m
Figure 5‐3: General test setup 5.2.6.2
a.
Bonding of EUT
Only the provisions included in the design of the EUT shall be used to bond units. 5.2.6.3
Shock and vibration isolators
a.
EUTʹs shall be secured to mounting bases having shock or vibration isolators if such mounting bases are used in the actual installation b.
The bonding straps furnished with the mounting base shall be connected to the ground plane. c.
When mounting bases do not have bonding straps, bonding straps shall not be used in the test setup. 5.2.6.4
a.
Safety grounds
When external terminals, connector pins, or equipment grounding conductors are available for safety ground connections and are used in the actual installation, they shall be connected to the ground plane. NOTE 5.2.6.5
Arrangement and length are specified in 5.2.6.6. Orientation of EUT's
a.
EUTʹs shall be oriented such that surfaces that produce maximum radiated emissions and respond most readily to radiated signals face the measurement antennas. b.
Bench mounted EUTs comprising interconnecting cables shall be located (10 ± 2) cm from the front edge of the ground plane. 30 ECSS‐E‐ST‐20‐07C 31 July 2008 5.2.6.6
Construction and arrangement of EUT cables
5.2.6.6.1
General
a.
Electrical cable assemblies shall simulate actual installation and usage. NOTE 1 Proper construction techniques such as use of twisted pairs, shielding, and shield terminations are determinant features. NOTE 2 Details on the cable construction used for testing are defined in the EMEVP DRD of ECSS‐E‐ST‐20, and maintained in the EMEVR DRD of ECSS‐E‐ST‐20. b.
Shielded cables or shielded leads (including power leads and wire grounds) within cables shall be used only if they have been specified in installation requirements. 5.2.6.6.2
Interconnecting leads and cables
a.
Individual leads shall be grouped into cables in the same manner as in the actual installation. b.
Up to 10 m, interconnecting cable lengths in the setup shall be the same as in the actual installation. c.
If a cable is longer than 10 m in the actual installation, the cable length in the set up shall be between 10 m and the actual length. d.
The cable arrangement shall be such that it satisfies the following conditions: 1.
At least the first 2 m (except for cables that are shorter in the actual installation) of each interconnecting cable associated with each enclosure of the EUT are run parallel to the front boundary of the setup. 2.
Remaining cable lengths are routed to the back of the setup and placed in a zigzagged arrangement. e.
When the setup includes more than one cable, individual cables shall be separated by 2 cm measured from their outer circumference. f.
For bench top setups using ground planes, the cable closest to the front boundary shall be placed 10 cm from the front edge of the ground plane. g.
All cables shall be supported 5 cm above the ground plane (except for interconnecting cables between enclosures of the EUT that are higher in the actual installation). 5.2.6.6.3
Input power leads
a.
Two metres of input power leads (including neutrals and returns) shall be routed parallel to the front edge of the setup in the same manner as the interconnecting leads. b.
Each input power lead, including neutrals and returns, shall be connected to a LISN. 31 ECSS‐E‐ST‐20‐07C 31 July 2008 c.
Power leads that are bundled, as part of an interconnecting cable in the actual installation, shall be configured in the same fashion for the 2 m exposed length and then shall be separated from the bundle and routed to the LISNʹs. d.
After the 2 m exposed length, the power leads shall be terminated at the LISNʹs in such a manner that the total length of power lead from the EUT electrical connector to the LISNʹs shall not exceed 2,5 m. e.
All power leads shall be supported 5 cm above the ground plane. f.
If the power leads are twisted in the actual installation, they shall be twisted up to the LISNʹs 5.2.6.7
a.
Electrical and mechanical interfaces
Either the actual equipment from the platform installation or loads that simulate the electrical properties present in the actual installation shall terminate electrical input or output interfaces. NOTE Example of these electrical properties are impedance, grounding and balance. b.
Signal inputs shall be applied to the electrical interfaces to exercise EUT circuitry. c.
EUT with mechanical outputs shall be loaded under expected conditions. d.
When variable electrical or mechanical loading is present in the actual installation, testing shall be performed under expected worst‐case conditions. e.
When active electrical loading is used, it shall be ensured that the active load meets the ambient requirements of 5.2.2 when connected to the setup, and that the active load does not respond to susceptibility signals. NOTE f.
Example of active electrical loading is the test set. Antenna ports on the EUT shall be terminated with shielded, matched loads if the RF link is not used during the test. 5.2.7
Operation of EUT
5.2.7.1
General
a.
During emission measurements, the EUT shall be placed in the operating mode, which produces maximum emissions. b.
During susceptibility testing, the EUT shall be placed in its most susceptible operating mode. c.
When the EUT has several available modes (including software controlled operational modes), the number of modes to be tested for emission and susceptibility shall be such that all circuitry is evaluated. NOTE It is expected that the customer defines or agrees operating modes. 32 ECSS‐E‐ST‐20‐07C 31 July 2008 5.2.7.2
a.
Measurements shall be performed with the EUT tuned to not less than three frequencies within each tuning band, tuning unit, or range of fixed channels, consisting of one mid‐band frequency and a frequency within ±5% from each end of each band or range of channels. 5.2.7.3
a.
Operating frequencies for spread spectrum
equipment
Operating frequency requirements for two major types of spread spectrum equipment shall be as follows: 1.
frequency hopping: measurements are performed with the EUT utilizing a hop set which contains a minimum of 30 % of the total possible frequencies, and the hop set is divided equally into three segments at the low, mid, and high end of the EUT operational frequency range, 2.
direct sequence: measurements are performed with the EUT processing data at the highest possible data transfer rate. 5.2.7.4
a.
Operating frequencies for tuneable RF equipment
Susceptibility monitoring
The EUT shall be monitored during susceptibility testing for indications of degradation or malfunction. NOTE b.
This monitoring is normally accomplished using built‐in‐test, visual displays, aural outputs, and other measurements of signal outputs and interfaces. If EUT performance is monitored through installation of special circuitry in the EUT, the modifications shall not influence test results. 5.2.8
Use of measurement equipment
5.2.8.1
Overview
Any frequency selective measurement receiver can be used for performing the testing described in this standard if the receiver characteristics (that is sensitivity, selection of bandwidths, detector functions, dynamic range, and frequency of operation) meet the constraints specified in this standard and are sufficient to demonstrate compliance with the applicable limits. 5.2.8.2
a.
Detector
A peak detector shall be used for all frequency domain emission and susceptibility measurements. NOTE This device detects the peak value of the modulation envelope in the receiver pass band. Measurement receivers are calibrated in terms of 33 ECSS‐E‐ST‐20‐07C 31 July 2008 an equivalent root mean square value of a sine wave that produces the same peak value. b.
When measurement devices other than peak detector are used for susceptibility testing, correction factors shall be determined and applied for test signals to adjust the reading to equivalent r.m.s. values under the peak of the modulation envelope. NOTE 5.2.8.3
a.
Example of such measurement devices are oscilloscopes, non‐selective voltmeters, and field strength sensors. Calibration fixture (jig)
When current measurements are performed on the central line of a coaxial transmission line a transmission line with 50 Ω characteristic impedance, coaxial connections on both ends, and space for an injection probe around the centre conductor shall be used for calibration. NOTE Figure 5‐4 represents an arrangement described in MIL‐STD‐461E. Figure 5‐4: Typical calibration fixture 5.2.9
Emission testing
5.2.9.1
Bandwidths
a.
The measurement receiver bandwidths listed in Table 5‐2 shall be used for emission testing. NOTE b.
These bandwidths are specified at the 6 dB down points for the overall selectivity curve of the receivers. Video filtering shall not be used to bandwidth limit the receiver response. 34 ECSS‐E‐ST‐20‐07C 31 July 2008 c.
If a controlled video bandwidth is available on the measurement receiver, it shall be set to its greatest value. d.
If receiver bandwidths larger that those in Table 5‐2 are used, no bandwidth correction factors shall be applied to test data due to the use of larger bandwidths. NOTE Larger bandwidths can result in higher measured emission levels. Table 5‐2: Bandwidth and measurement time Frequency Range 6 dB bandwidth Dwell time Minimum measurement time (analogue measurement receiver) 30 Hz ‐ 1 kHz 10 Hz 0,15 s 0,015 s/Hz 1 kHz ‐ 10 kHz 100 Hz 0,015 s 0,15 s/kHz 10 kHz ‐ 150 kHz 1 kHz 0,015 s 0,015 s/kHz 150 kHz ‐ 30 MHz 10 kHz 0,015 s 1,5 s/MHz 30 MHz ‐ 1 GHz 100 kHz 0,015 s 0,15 s/MHz Above 1 GHz 1 MHz 0,015 s 15 s/GHz 5.2.9.2
a.
Emission identification
All emissions regardless of characteristics shall be measured with the measurement receiver bandwidths specified in Table 5‐2. 5.2.9.3
Frequency scanning
a.
For emission measurements, the entire frequency range for each test shall be scanned. b.
Minimum measurement time for analogue measurement receivers during emission testing shall be as specified in Table 5‐2. c.
Synthesized measurement receivers shall step in one‐half bandwidth increments or less, and the measurement dwell time shall be as specified in Table 5‐2. d.
For equipment that operates, such that potential emissions are produced at only infrequent intervals, times for frequency scanning shall be increased such than any emission is captured. 5.2.9.4
Emission data presentation
a.
Amplitude versus frequency profiles of emission data shall be automatically generated and displayed at the time of the test. b.
Except for verification of the validity of the output, data shall not be gathered manually. c.
The information shall be displayed after application of correction factors, including transducers, attenuators, and cable loss. 35 ECSS‐E‐ST‐20‐07C 31 July 2008 d.
Data output of the EUT test result shall be in the form of amplitude over time (for the time domain plots) and amplitude over frequency (for frequency domain plots), superimposed with the EMI test limit. e.
Units of measurement for frequency domain emissions measurements shall be reported in units of dB referenced to 1 μV, 1 μA, 1 μV/m, 1 pT depending on the unit defined in the test limit. f.
For time domain measurements, oscilloscope plots shall include the amplitude physical unit (V or A) conversion factors V into A if not done automatically by the oscilloscope, and the oscilloscope sensitivity, time base settings and measurement bandwidth. g.
For frequency domain plots, emission data shall be reported in graphic form with frequency resolution of 1 %, or twice the measurement receiver bandwidth, whichever is less stringent. h.
In the event of any emissions test result over the emission test limit above 100 MHz, greater accuracy of its frequency shall be reported with resolution better than or equal to twice the measurement bandwidth. i.
Each plot of emission data shall be reported with a minimum amplitude resolution of 1 dB. 5.2.10
Susceptibility testing
5.2.10.1
Frequency stepping
a.
For susceptibility measurements, the entire frequency range for each applicable test shall be scanned. NOTE b.
Stepped scans shall dwell at each tuned frequency for the greatest of three seconds or the EUT response time. NOTE c.
Stepped scans refer to signal sources that are sequentially tuned to discrete frequencies. Ten frequency steps per decade can be used as a basis. Step sizes shall be decreased such to permit observation of a response. NOTE 5.2.10.2
For receivers, it can make use of the frequency plan to adjust the number of points. Modulation of susceptibility signals
a.
Susceptibility test signals shall be pulse modulated (on/off ratio of 40 dB minimum) at a 1 kHz rate with a 50 % duty cycle for susceptibility signals at a frequency larger than 100 kHz. b.
CW test signals shall be used for susceptibility signals at a frequency smaller than 100 kHz. 36 ECSS‐E‐ST‐20‐07C 31 July 2008 5.2.10.3
a.
Thresholds of susceptibility
When susceptibility indications are noted in EUT operation, a threshold level shall be determined as follows where the susceptible condition is no longer present: 1.
When a susceptibility condition is detected, reduce the interference signal until the EUT recovers. 2.
Reduce the interference signal by an additional 6 dB. 3.
Gradually increase the interference signal until the susceptibility condition reoccurs; the resulting level is the threshold of susceptibility. 4.
Record this level, frequency range of occurrence, frequency and level of greatest susceptibility, and the other test parameters. 5.2.10.4
Susceptibility data presentation
a.
The susceptibility criteria defined in the EMI test procedure shall be repeated in the test report, or the “as run” EMI test procedure shall be an annex to the EMI test report. b.
Data showing the frequencies and amplitudes at which the test was conducted shall be provided in graphical or tabular form. c.
Indications of compliance with the requirements shall be provided. NOTE Such indications can be provision of oscilloscope plots of injected waveforms with test data. d.
Information shall be displayed after application of correction factors, including transducers, attenuators, and cable loss. e.
Data shall be reported with frequency resolution of 1 %. f.
Data shall be provided with a minimum amplitude resolution of 1 dB for each plot. g.
If susceptibility is observed, determined levels of susceptibility shall be recorded in the test report. 5.2.11
Calibration of measuring equipment
5.2.11.1
General
a.
Measurement antennas, current probes, field sensors, and other devices used in the measurement loop shall be calibrated at least every two years or when damaged. 5.2.11.2
a.
Measurement system test
At the start of each emission test, the complete test system (including measurement receivers, cables, attenuators, couplers, and so forth) shall be verified by injecting a known signal (as stated in the individual test procedure), while monitoring system output for the proper indication. 37 ECSS‐E‐ST‐20‐07C 31 July 2008 b.
When the emission test involves an uninterrupted set of repeated measurements using the same measurement equipment, the measurement system test may be accomplished only one time. NOTE 5.3
Example of such repeated measurements is the evaluation of different operating modes of the EUT. System level
5.3.1
a.
Each item of equipment and subsystem shall have successfully passed functional acceptance test procedures as installed on the platform, prior to system level EMC test. 5.3.2
a.
b.
General
Safety margin demonstration for critical or
EED circuits
A test performed to demonstrate compliance with the safety margin requirement shall use one or more of the following test approaches: 1.
Inject interference at critical system points at x dB higher level than exists, while monitoring other system points for improper responses, where x = EMISM. 2.
Measure the susceptibility of critical system circuits for comparison to existing interference levels, to determine the margin. 3.
Sensitize the system to render it x dB more susceptible to interference, while monitoring for improper response, where x = EMISM. Safety margin demonstration for something that is susceptible to a time domain circuit (including EED’s) shall use time domain methods. 5.3.3
EMC with the launch system
a.
If the spacecraft is not powered during launch, EMC test with the launch system need not be performed. b.
If the spacecraft is powered during launch, the electric field radiation, including intentional transmission, shall be measured at locations specified in the Launcher User’s manual. c.
In case of a transmitting spacecraft under fairing, the EMISM applied to EEDʹs shall be verified. 38 ECSS‐E‐ST‐20‐07C 31 July 2008 5.3.4
a.
Lightning
Lightning protection specified in ECSS‐E‐ST‐20 (in clause “Inter‐system EMC and EMC with environment’), shall be verified by analysis from equipment demonstration. NOTE 1 Test at system level need not be performed. NOTE 2 The bi‐exponential model defined in clause 4.2.3.2 is generally used. 5.3.5
Spacecraft and static charging
a.
Material use, bonding of discharge elements, thermal blankets, or metallic items using a bond for static potential equalization shall be verified by inspection or measurement at assembly into structure. b.
If the bond is only used for charging control, the bonding resistance shall be measured with a dc‐current in the range 10 to 100 μA, under only one polarity, with a 2‐wires ohmmeter. NOTE 5.3.6
a.
If the bond is only used for charging control the clauses 5.3.10a and 5.3.10b do not apply. Spacecraft DC magnetic field emission
Spacecraft DC magnetic field emission requirements shall be verified by a combination of analysis and tests. 5.3.7
Intra–system electromagnetic compatibility
a.
For intra‐system EMC tests, the support equipment shall provide the functionality of exercising culprits and victims, and include the support equipment instructions. b.
Wherever 0 dB EMISM is a requirement, functional tests at spacecraft level may be accepted as a verification of EMC. 5.3.8
Radiofrequency compatibility
a.
Except for passive intermodulation products, compatibility shall be verified by a test at system level. radiofrequency b.
Absence of passive intermodulation products shall be verified in accordance with the requirements for “Passive intermodulation” specified in ECSS‐E‐ST‐20. 39 ECSS‐E‐ST‐20‐07C 31 July 2008 5.3.9
a.
Grounding
The system‐level electrical grounding and isolation shall be verified by isolation and continuity tests at system assembly. NOTE 5.3.10
Electrical bonding
a.
Except for bonding used only for charging control, the bonding resistances shall be measured using a 4‐wires method, under a pulsed DC current of 1 A. b.
Except for bonding used only for charging control, the probes shall be reversed and re‐measured to detect possible non linearities across the bonded junction. NOTE 5.3.11
a.
5.4
The grounding and isolation design is documented by the system‐level grounding diagram including EGSE. See clause 5.3.5b. Wiring and shielding
Wiring category and cable shields shall be verified by review of design and inspection. Equipment and subsystem level test procedures
5.4.1
Overview
Test procedures are specified in clauses 5.4.2 through 5.4.11.4 for verifying emission and susceptibility requirements at subsystem or equipment level. Table 5‐3 gives the correspondence between procedures and recommended limits defined in Annex A. 40 ECSS‐E‐ST‐20‐07C 31 July 2008 Table 5‐3: Correspondence between test procedures and limits Informative limit Annex A
Title of test procedure Verification Clause 5
A.2
CE on power leads, differential mode, 30 Hz to 100 kHz (1st part) 5.4.2
A.2
CE on power leads, differential mode, 100 kHz to 100 MHz (2nd part) 5.4.3
A.3
CE on power leads, in‐rush currents
5.4.3.4
A.4
CE on power and signal leads, common mode, 100 kHz to 100 MHz
5.4.3
A.5
CE on antenna ports
Specific A.6
DC magnetic field emission
5.4.4.4
A.7
RE, low‐frequency magnetic field
Specific A.8
RE, low‐frequency electric field
Specific A.9
RE, electric field, 30 MHz to 18 GHz
5.4.6
A.10
CS, power leads, differential mode, 30 Hz to 100 kHz.
5.4.6.4
A.11
CS, power and signal leads, common mode, 50 kHz to 100 MHz
5.4.7.4
A.12
CS, power leads, short spike transients
5.4.9
A.13
RS, magnetic field, 30 Hz to 100 kHz
5.4.9.4
A.14
RS, electric field, 30 MHz to 18 GHz
5.4.10.4
A.15
Susceptibility to electrostatic discharge
5.4.11.4
5.4.2
CE, power leads, differential mode, 30 Hz to
100 kHz
5.4.2.1
Purpose
This method is used for measuring conducted emissions in the frequency range 30 Hz to 100 kHz on all input power leads including returns. 5.4.2.2
a.
Test equipment
The test equipment shall be as follows: 1.
Measurement receiver, 2.
Current probe, 3.
Signal generator with amplifier, 4.
DC‐current supply, 5.
Data recording device, 6.
Oscilloscope, 7.
Coaxial “T” connector and coaxial to bifilar transition, 8.
1 Ω and 10 Ω power metal film resistors with inductance lower than 100 nH, 9.
LISN defined in 5.2.4. 41 ECSS‐E‐ST‐20‐07C 31 July 2008 5.4.2.3
a.
The test setup shall be as follows: 1.
Maintain a basic test setup for the EUT as specified in 5.2.6 and Figure 5‐3. 2.
For measurement system check, configure the test setup as shown in Figure 5‐5. 3.
For equipment testing, configure the test setup as shown Figure 5‐6. 5.4.2.4
a.
Setup
Procedure
The test procedures shall be as follows: 1.
Turn on the measurement equipment and wait until it is stabilized. 2.
If the EMEVP specifies to check the measurement system, check it by evaluating the overall measurement system from the current probe to the data output device, as follows: (a)
Apply a calibrated signal level, at 1 kHz and 100 kHz, which is at least 6 dB below the emission limit to the current probe. NOTE (b)
A power amplifier can be necessary at 1 kHz. Apply through the current probe a DC‐current equivalent to the EUT supply current. NOTE 1 A DC current is applied for verifying that the current probe will not be saturated by the EUT DC supply current. NOTE 2 This DC current is applied through the LISN for applying the same impedance through the probe as with the EUT. 3.
(c)
Verify the AC current level as measured with the probe by comparison with voltage across the 1 Ω resistor at 1 kHz and the 10 Ω resistor at 100 kHz; also, verify that the current waveform is sinusoidal. (d)
Scan the measurement receiver for each frequency in the same manner as a normal data scan. Verify that the data‐
recording device indicates a level within ±3 dB of the injected level. (e)
If readings are obtained which deviate by more than ±3 dB, locate the source of the error and correct the deficiency prior to proceeding with the testing. Test the EUT by determining the conducted emissions from the EUT input power leads, hot line and return, and measure the conducted emission separately on each power lead, as follows: (a)
Turn on the EUT and wait for its stabilization. (b)
Select a lead for testing and clamp the current probe into position. 42 ECSS‐E‐ST‐20‐07C 31 July 2008 (c)
Scan the measurement receiver over the frequency range, using the bandwidths and minimum measurement times specified in Table 5‐2, clause 5.2.9.1. (d)
Repeat 5.4.2.4a.3(b) and 5.4.2.4a.3(c) for each power lead. Measurement
receiver
Oscilloscope
Data
recorder
Coax “T” and
bifilar
transition
Signal
generator
with
amplifier
LISN
To power source
Current
Resistor probe
Figure 5‐5: Conducted emission, 30 Hz to 100 kHz, measurement system check Measurement
receiver
Data recorder
Current
probe
LISN
EUT
To power source
Figure 5‐6: Conducted emission, 30 Hz to 100 kHz, measurement setup 5.4.3
CE, power and signal leads, 100 kHz to 100
MHz
5.4.3.1
Purpose
This test procedure is used to verify that electromagnetic emissions from the EUT do not exceed the specified requirements for power input leads including returns, and for common mode emission. 5.4.3.2
a.
Test equipment
The test equipment shall be as follows: 1.
Measurement receiver, 2.
Current probe, 3.
Signal generator, 43 ECSS‐E‐ST‐20‐07C 31 July 2008 4.
Data recording device, 5.
Oscilloscope with 50 Ω input, 6.
50 Ω power divider (6dB “T” connector), 7.
50 Ω coaxial load, 8.
Calibration fixture defined in 5.2.8.3, 9.
LISNʹs defined in 5.2.4. 5.4.3.3
a.
Setup
The test setup shall be as follows: 1.
Maintain a basic test setup for the EUT as specified in 5.2.6 and Figure 5‐3. 2.
Configure the test setup for the measurement system check as shown in Figure 5‐7. 3.
For compliance testing of the EUT: (a)
Configure the test setup as shown in Figure 5‐8. (b)
Position the current probe 10 cm from the LISN. Measurement
receiver
Oscilloscope
50Ω input
Signal
generator
Current probe
inside jig
Data
recorder
50Ω coaxial
load
6dB
T-connector
LISN
To power source
Figure 5‐7: Conducted emission, measurement system check Measurement
receiver
Data recorder
Current
probe
EUT
LISN
To power source
Figure 5‐8: Conducted emission, measurement setup in differential mode 44 ECSS‐E‐ST‐20‐07C 31 July 2008 Measurement
receiver
Data recorder
OR
To power source
Power lines
EUT
LISN
or EGSE
Signal lines
EGSE
Current probe
Figure 5‐9: Conducted emission, measurement setup in common mode 5.4.3.4
a.
Procedures
The test procedures shall be as follows: 1.
Turn on the measurement equipment and wait until it is stabilized. 2.
If the EMEVP specifies to check the measurement system, check it by evaluating the overall measurement system from the current probe to the data output device, as follows: (a)
Apply a calibrated signal level that is at least 6 dB below the applicable limit at 1 MHz and 10 MHz or at a level allowing out of the noise reading on the oscilloscope, whatever is greater, to the current probe in the jig. (b)
Apply through the current probe using a second wire, a DC current equivalent to the EUT nominal supply current. NOTE 1 A DC current is applied for verifying that the current probe will not be saturated by the EUT DC supply current. NOTE 2 This DC current is applied through the LISN for applying the same impedance through the probe as with the EUT. 3.
(c)
Verify the AC current level, as measured with the probe by comparison with the voltage on the T derivation. (d)
Scan the measurement receiver for each frequency in the same manner as a normal data scan, and verify that the data‐
recording device indicates a level within ±3 dB of the injected level. (e)
If readings are obtained which deviate by more than ±3 dB, locate the source of the error and correct the deficiency prior to proceeding with the testing. Test the EUT by determining the conducted emission from the input power leads, hot lines and returns separately, and from each interconnecting bundle (common mode), including the ones with power leads, as follows: 45 ECSS‐E‐ST‐20‐07C 31 July 2008 (a)
Turn on the EUT and wait until it is stabilized. (b)
Select a lead or a bundle for testing and clamp the current probe into position. (c)
Scan the measurement receiver over the frequency range, using the bandwidths and minimum measurement times specified in Table 5‐2, clause 5.2.9.1. (d)
Repeat 5.4.3.4a.3(b) and 5.4.3.4a.3(c) for each power lead or for each bundle. 5.4.4
CE, power leads, inrush current
5.4.4.1
Purpose
This test procedure is used to verify that the inrush current of the EUT does not exceed the specified requirements for power input leads. 5.4.4.2
a.
The test equipment shall be as follows: 1.
Two‐channels oscilloscope, 2.
Current probe, 3.
Spike generator, 4.
Data recording device, 5.
Coaxial “T” connector, 6.
Coaxial to bifilar transition, 7.
1 Ω power metal film resistor with inductance lower 30 nH and peak power capability, 8.
LISN defined in 5.2.4, 9.
Switching device, fast bounce‐free power switch, or an actual power‐controller except if the ON/OFF command is implemented in the EUT. 5.4.4.3
a.
Test equipment
Setup
The test setup shall be as follows: 1.
Maintain a basic test setup for the EUT as specified in 5.2.6 and Figure 5‐3. 2.
Configure the test setup for the measurement system check as shown in Figure 5‐10. 3.
Configure the test setup for compliance testing of the EUT as shown in Figure 5‐11. 46 ECSS‐E‐ST‐20‐07C 31 July 2008 Data
recorder
Oscilloscope
Coax “T”
and bifilar
transition
Spike
generator
LISN
To power source
Current
probe
Resistor
Figure 5‐10: Inrush current: measurement system check setup Oscilloscope
Current probe
Data recorder
Fast bounce-free
power switch
a
EUT
Power
controller
c
b
LISN
To power source
ON/OFF command
Figure 5‐11: Inrush current: measurement setup 5.4.4.4
a.
Procedures
The test procedures shall be as follows: 1.
Turn on the measurement equipment and allow a sufficient time for stabilization. 2.
If specified by the EMEVP, check the measurement system by evaluating the overall measurement system from the current probe to the data output device: (a)
Apply a calibrated spike that is at least 6 dB below the applicable limit to the current probe. (b)
Apply through the current probe a DC current equivalent to the EUT supply current. NOTE 1 A DC current is applied for verifying that the current probe will not be saturated by the EUT DC supply current. NOTE 2 This DC current is applied through the LISN for applying the same impedance through the probe as with the EUT. 47 ECSS‐E‐ST‐20‐07C 31 July 2008 3.
(c)
Check the spike current as measured with the probe by comparison with the voltage across the resistor. (d)
Perform the measurement with the current probe on an oscilloscope in the same manner as for EUT testing and verify that the data‐recording device indicates a level within ±3 dB of the injected level. (e)
If readings are obtained which deviate by more than ±3 dB, locate the source of the error and correct the deficiency prior to proceeding with the testing. Test the EUT by determining the conducted emission from the EUT input power leads, as follows: (a)
Select the positive lead for testing and clamp the current probe into position. (b)
Perform measurement by application of power on the EUT using a mercury relay (Figure 5‐11.a), the internal EUT switch (Figure 5‐11.c), or the power controller (Figure 5‐11.c). NOTE 5.4.4.5
a.
Data presentation
In addition to 5.2.9.4, data presentation shall be a graphic output of current versus time displaying the transient characteristics with following conditions: 1.
amplitude resolution within 3 % of the applicable limit, 2.
time base resolution within 10 % of rise time for measurement of rise and fall slopes. NOTE b.
The method for application of power is defined in the EMEVR Rise time is the duration between 10 % and 90 % of peak‐to‐peak amplitude Two separate displays shall be provided showing respectively the initial rise time and the full inrush response. NOTE Typica1 time bases are 10 μs full scale for the initial rise time and 1 ms full scale for the full inrush response. 5.4.5
DC Magnetic field emission, magnetic
moment
5.4.5.1
Overview
The described test method allows obtaining a rough estimate of the magnetic moment of the EUT (centred dipole approximation). It involves the constraint of measuring the magnetic field at distances typically more than three times the size of the EUT. 48 ECSS‐E‐ST‐20‐07C 31 July 2008 If a better model is needed, making it possible to predict the field at closer distances or more precisely than the centred dipole approximation allows, then either multiple dipole modelling techniques or spherical harmonics techniques can be used. NOTE 5.4.5.2
a.
It is the role of the EMCAB to assess the need for using such techniques, based on mission requirements. Set-Up
The EUT should be set in an earth field compensated area providing zero‐field conditions for the intrinsic moment determination. NOTE 1 This is necessary in case the EUT contains a significant amount of soft magnetic material, as without earth field compensation an induced magnetic moment would appear. NOTE 2 Earth field compensation is usually ensured by 2 or 3 sets of Helmholtz coils. b.
A right‐handed orthogonal coordinate system XYZ shall be assigned to the EUT geometric centre. c.
The magnetic sensor (single‐axis magnetometer) shall be installed successively on the 6 semi‐axes at two different reference distances r1 and r2 from the geometric centre of the EUT and shall measure the field projection along these lines. NOTE The reference distances are typically more than three times the size of the EUT d.
Alternatively the EUT may be installed on a turntable and rotated in front of a fixed magnetometer, presenting each XYZ axis (positive and negative) successively aligned with the sensor axis. e.
The magnetic field shall be positive when orientated from the centre of the EUT towards the magnetometer. 5.4.5.3
a.
Test sequence
The test sequence shall be as follows: 1.
EUT not operating, initial measurements on the six semi‐axes at the reference distances. 2.
Deperm: (a)
EUT not operating, application of a deperming field in accordance with Figure 5‐12 frequency 3 Hz, maximum amplitude between 4 000 μT and 5 000 μT, successively on each XYZ axis of the EUT. NOTE 1 This is usually done using Helmholtz coils. NOTE 2 A sequence of symmetrical sine periods of increasing and decreasing amplitude gives better results than a sine wave modulated by exponentials or ramp functions. 49 ECSS‐E‐ST‐20‐07C 31 July 2008 (b)
3.
Perm: (a)
EUT not operating, application of a perm field of 300 μT on each XYZ axis. (b)
Measurement after perm on the six semi‐axes at the reference distances. 4.
Stray field: EUT operating, measurement on the six semi‐axes at the reference distances. 5.
Final deperm: repeat 5.4.5.3a.2. 5.4.5.4
a.
Measurement after deperm on the six semi‐axes at the reference distances. Data presentation
For DC magnetic field emission, data shall be presented as follows, superseding clauses 5.2.9.4a through 5.2.9.4i: 1.
For each measurement distance, for each of the 6 semi‐axes, the following induction measurements in μT are plotted in tabular form: B(+X), B(‐X), B(+Y), B(‐Y), B(+Z), B(‐Z) B
2.
For each measurement distance, mean inductions, for each axis, are computed in units of μT and plotted in tabular form, using following equations: BX =
3.
B
B(+ X ) − B(− X )
2
, BY =
B − B(−Z )
B(+ Y ) − B(−Y )
, BZ = ( + Z )
2
2
For each measurement distance r, 3‐axes magnetic moment components in units of Am² are calculated using the following equations and reported: Mx = 5 r3 BX M in units of Am², r in meters, B in μT My = 5 r3 BY Mz = 5 r3 BZ 4.
Using values of Mx, My and Mz at both distances r1 and r2, values M1 and M2 of the magnetic moment are calculated using the following equations and reported: NOTE M1 =
Mx(r1)2 + My(r1)2 + Mz(r1)2
M2 =
Mx(r2)2 + My(r2)2 + Mz(r2)2
If the EUT is a centred dipolar source, then M1 = M2. 50 ECSS‐E‐ST‐20‐07C 31 July 2008 deperm field
5000 µT
< 0.03 µT
at switch off
B (µT)
Decrease : 1 %
Increase : 2 %
- 5000 µT
time
Increase : t > 200 s
Decrease : t > 400 s
Figure 5‐12: Smooth deperm procedure 5.4.6
RE, electric field, 30 MHz to 18 GHz
5.4.6.1
Purpose
This test procedure is used to verify that electric field emissions from the EUT and its associated cabling do not exceed specified requirements. 5.4.6.2
a.
Test equipment
The test equipment shall be as follows: 1.
Measurement receiver, 2.
Data recording device, 3.
Linearly polarized antennas, NOTE The following antennas are commonly used: • 30 MHz to 200 MHz, biconical, 137 cm tip to tip, • 200 MHz to 1 GHz, double ridge horn, 69,0 cm by 94,5 cm opening, or log‐periodic, • 1 GHz to 18 GHz, double ridge horn, 24,2 cm by 13,6 cm opening. 4.
Signal generators, 5.
Stub radiator, 6.
LISN defined in 5.2.4, optional. 51 ECSS‐E‐ST‐20‐07C 31 July 2008 5.4.6.3
a.
Test setup
A basic test setup for the EUT as shown and described in Figure 5‐3 and 5.2.6 shall be maintained to ensure that the EUT is oriented such that the surface that produces the maximum radiated emissions is toward the front edge of the test setup boundary. NOTE The LISN should be used. b.
The measurement system shall be checked by configuring the test equipment as shown in Figure 5‐13. c.
To test the EUT antenna positioning, the test setup boundary of the EUT and associated cabling for use in positioning of antennas shall be determined. d.
To test the EUT antenna positioning, the physical reference points on the antennas shown in Figure 5‐14 for measuring heights of the antennas and distances of the antennas from the test setup boundary shall be used as follows: e.
1.
Position antennas 1 m from the front edge of the test setup boundary for all setups. 2.
Position antennas above the floor ground plane. 3.
Ensure that no part of any antenna is closer than 1 m from the walls and 0,5 m from the ceiling of the shielded enclosure. The antenna positions shall be determined as follows: 1.
For testing below 200 MHz: (a)
For setups with the side edges of the boundary 3 m or less, one position, with the antenna centred with respect to the side edges of the boundary. (b)
For setups with the side edges of the boundary greater than 3 m, N antenna positions at spacing as shown in Figure 5‐15, where N is the edge‐to‐edge boundary distance (in metres) divided by 3 and rounding up to an integer. 2.
For testing from 200 MHz up to 1 GHz, place the antenna in such a number of positions that the entire width of each EUT enclosure and the first 35 cm of cables and leads interfacing with the EUT enclosure are within the 3 dB beamwidth of the antenna. 3.
For testing at 1 GHz and above, place the antenna in such a number of positions that the entire width of each EUT enclosure and the first 7 cm of cables and leads interfacing with the EUT enclosure are within the 3 dB‐beamwidth of the antenna. 52 ECSS‐E‐ST‐20‐07C 31 July 2008 Test setup boundary
Antenna
Shielded enclosure Signal generator Connected for system check Connected for measurement Measurement receiver Data recording device Figure 5‐13: Electric field radiated emission. Basic test setup Antenna Test setup boundary Ground plane 1,2 m 0,9 m
Floor 1 m Figure 5‐14: Electric field radiated emission. Antenna positioning 53 ECSS‐E‐ST‐20‐07C 31 July 2008 Test setup boundary
Length x(m); N positions = x/3 (rounded up nearest integer) 1 m
Antenna x/2 N (m)
Antenna Antenna
x/N (m)
x/N (m)
x/2 N (m)
Shielded enclosure Figure 5‐15: Electric field radiated emission. Multiple antenna positions 5.4.6.4
Test procedures
a.
The measurement equipment shall be turned on and waited until it is stabilized. b.
It shall be verify that the ambient requirements specified in 5.2.2.3 are met and plots of the ambient taken. c.
The measurement system shall be checked as follows: 1.
2.
Using the system check path of Figure 5‐13, perform the following evaluation of the overall measurement system from each antenna to the data output device at the highest measurement frequency of the antenna: (a)
Apply a calibrated signal level that is at least 6 dB below the limit (limit minus antenna factor) to the coaxial cable at the antenna connection point. (b)
Scan the measurement receiver in the same manner as a normal data scan, and verify that the data‐recording device indicates a level within ±3 dB of the injected signal level. (c)
If readings are obtained which deviate by more than ±3 dB, locate the source of the error and correct the deficiency prior to proceeding with the testing. Using the measurement path of Figure 5‐13, perform the following evaluation for each antenna to demonstrate that there is electrical continuity through the antenna: (a)
Radiate a signal using an antenna or stub radiator at the highest measurement frequency of each antenna. (b)
Tune the measurement receiver to the frequency of the applied signal and verify that a received signal of appropriate amplitude is present. NOTE This evaluation is intended to provide a coarse indication that the antenna is functioning properly. 54 ECSS‐E‐ST‐20‐07C 31 July 2008 There is no requirement to measure accurately the signal level. d.
The EUT shall be tested by using the measurement path of Figure 5‐13 and by determining the radiated emissions from the EUT and its associated cabling as follows: 1.
Turn on the EUT and wait until it is stabilized. 2.
Scan the measurement receiver for each applicable frequency range, using the bandwidths and minimum measurement times in 5.2.9.1 3.
Orient the antennas for both horizontally and vertically polarized fields. 4.
Repeat steps 5.4.6.4d.2 and 5.4.6.4d.3 for each antenna position determined under 5.4.6.3c, 5.4.6.3d, and 5.4.6.3e. 5.4.6.5
a.
Data Presentation
In addition to 5.2.9.4, data presentation shall provide a statement verifying the electrical continuity of the measurement antennas as determined in 5.4.6.4c.1(c). 5.4.7
CS, power leads, 30 Hz to 100 kHz
5.4.7.1
Purpose
This test procedure is used to verify the ability of the EUT to withstand signals coupled on input power leads. 5.4.7.2
a.
The test equipment shall be as follows: 1.
Signal generator, 2.
Power amplifier, 3.
1,5 Ω to 2,7 Ω power metal film resistor with inductance lower 1 000 nH and peak power capability, 4.
Oscilloscopes, 5.
Current probe, 6.
Differential high voltage‐probe, 7.
injection transformer, 8.
LISN defined in 5.2.4 optional. 5.4.7.3
a.
Test equipment
Setup
The test setup shall be as follows: 1.
Maintain a basic test setup for the EUT as specified in 5.2.6 and Figure 5‐3. 55 ECSS‐E‐ST‐20‐07C 31 July 2008 2.
Check measurement system by configuring the test equipment in accordance with Figure 5‐16, and setting up the oscilloscope to monitor the voltage across the resistor. 3.
Test the EUT by configuring the test equipment as shown in Figure 5‐17. S ig n a l g e n e r a to r
P o w e r a m p lifie r
1 ,5 to 2 ,7 Ω
C u rre n t p robe R e sisto r In je c tio n tr a n sfo rm e r D a ta re c o r d e r O sc illo sc o p e d iffe re n tia l p ro b e
O sc illo sc o p e Figure 5‐16: CS, power leads, measurement system check set‐up Signal generator
Power am plifier
Stim ulation and m onitoring of EU T 1,5 to 2,7Ω
Current
probe
EU T O scilloscope Pow er inputs Injection transform er
LISN O scilloscope differential probe D ata recorder Figure 5‐17: CS, power leads, signal injection 56 ECSS‐E‐ST‐20‐07C 31 July 2008 5.4.7.4
Procedures
a.
The measurement equipment shall be turned on and waited until it is stabilized. b.
The measurement system shall be checked using the measurement system check setup for waveform verification as follows: c.
1.
Set the signal generator to the lowest test frequency. 2.
Increase the applied signal until the oscilloscope indicates the voltage level specified by application of clause 4.2.8, verify that the output waveform is sinusoidal, and verify that the indication given by the current probe is within 3 dB of the expected level derived from the 1 Ω resistor voltage. 3.
Repeat 5.4.7.4b.2 by setting the signal generator to the highest test frequency. The EUT shall be tested as follows: 1.
Turn on the EUT and wait until it is stabilized. 2.
Set the signal generator to the lowest test frequency, and increase the signal level until the testing voltage or current limit specified by application of clause 4.2.8, is reached on the power lead. 3.
Repeat 5.4.7.4c.2 at all frequency steps through the testing frequency range. 4.
Evaluate the susceptibility as follows. 5.
(a)
Monitor the EUT for degradation of performance. (b)
If susceptibility is noted, determine the threshold level in accordance with 5.2.10.3. Repeat 5.4.7.4c.2 to 5.4.7.4c.4 for each power lead. 5.4.8
CS, bulk cable injection, 50 kHz to 100 MHz
5.4.8.1
Purpose
This test procedure is used to verify the ability of the EUT to withstand sinusoidal waves coupled on the EUT associated cables and power leads. 5.4.8.2
a.
Test equipment
The test equipment shall be as follows: 1.
Signal generator with amplitude or pulse modulation capability, 2.
pulse generator, 1 kHz – 100 kHz, adjustable duty cycle, 3.
power amplifier, 50 kHz – 100 MHz, 4.
current injection probe, 50 kHz – 100 MHz, 5.
current measurement probe, 50 kHz – 100 MHz, 6.
one or two calibration fixture(s) (jigs) defined in 5.2.8.3, 57 ECSS‐E‐ST‐20‐07C 31 July 2008 7.
one two‐channels oscilloscope, 50 Ω input impedance, 8.
waveform recording device, 9.
50 Ω coaxial load, 10.
LISN defined in 5.2.4, 11.
spectrum analyzer (optional). 5.4.8.3
a.
Setup
The test setup shall be as follows: 1.
Maintain a basic test setup for the EUT as shown and described in 5.2.6 and Figure 5‐3. 2.
For calibration: (a)
Configure the test equipment in accordance with Figure 5‐18. (b)
Place the injection probe and the monitor probe around the central conductor of their respective jigs. NOTE 3.
The monitor probe and associated jig are optional. (c)
Terminate one end of the jig with a 50Ω‐coaxial load and connect the other end to a 50 Ω‐input oscilloscope. (d)
If a current monitor probe is used, connect it to another 50 Ω oscilloscope input. For testing the EUT: (a)
Configure the test equipment as shown Figure 5‐20. (b)
Place the injection and monitor probes around a cable bundle interfacing an EUT connector. (c)
Position the monitor probe: − 5 cm from the connector if the overall length of the connector and backshell does not exceed 5 cm, − at the overall length of the connector and backshell, otherwise. (d)
5.4.8.4
Position the injection probe 5 cm from the monitor probe. Test procedures
a.
The measurement equipment shall be turned on and waited until it is stabilized. b.
The measurement system shall be calibrated by performing the following procedures using the calibration setup: 1.
Set the frequency of the generator to 50 kHz and apply the pulse modulation, Figure 5‐19. 58 ECSS‐E‐ST‐20‐07C 31 July 2008 c.
2.
Increase the applied signal until the oscilloscope indicates the voltage specified by application of clause 4.2.8. 3.
Verify that both inputs of the oscilloscope, voltage monitored on 50 Ω and current monitored by the current probe, are consistent within 3 dB. This is applicable only if a current probe is used during calibration 4.
Record the generator settings. 5.
Repeat 5.4.8.4b.2 through 5.4.8.4b.4 for each measurement frequency. The EUT shall be tested by performing the following procedures and using the EUT test setup: 1.
Turn on the EUT and wait until it is stabilized. 2.
Select a bundle for testing and clamp the current probes into position. 3.
d.
(a)
Set the modulated sine generator to a test frequency, at low output level. (b)
Adjust the modulation in duty cycle and frequency. (c)
Increase the generator output to the level determined during calibration, without exceeding the current limit specified by application of clause 4.2.8 and record the peak current obtained. (d)
Monitor the EUT for degradation of performance. (e)
If susceptibility is noted, determine the threshold level as measured by the current monitor probe in accordance with 5.2.10.3. (f)
Repeat 5.4.8.4c.2(a) through 5.4.8.4c.2(e) for each test frequency. Repeat 5.4.8.4c.2. applying the test signals to each bundle interfacing with each connector or all bundles taken together. The calibration need not be re‐performed before testing each EUT bundle. 59 ECSS‐E‐ST‐20‐07C 31 July 2008 Ext mod
IN
External
modulation
source
Signal
generator
50Ω
Power
amplifier
Monitor probe
Oscilloscope 50Ω input
or spectrum analyser
Injection probe
Jig
Jig
50Ω coaxial load
Volt
Figure 5‐18: Bulk cable injection, measurement system check set‐up Time
Burst length
Period
Figure 5‐19: Signal test waveform External modulation source Ext mod IN Signal generator 50 Ω
Monitor probe Power amplifier
Injection probe EUT Oscilloscope/ Spectrum analyser
Data recorder LISN (or EUT, or EGSE) Figure 5‐20: CS of power and signal leads, bulk cable injection 60 ECSS‐E‐ST‐20‐07C 31 July 2008 5.4.9
CS, power leads, transients
5.4.9.1
Purpose
This test procedure is used to verify the ability of the EUT to withstand short spikes coupled on EUT power leads, including grounds and returns that are not grounded internally to the equipment or subsystem. 5.4.9.2
a.
The test equipment shall be as follows: 1.
Spike generator with following characteristics: (a)
Pulse width of 10 μs and 0,15 μs, (b)
Pulse repetition rate capability up to 10 pulses per second, (c)
Voltage output as required, positive then negative, (d)
Output control, (e)
Adequate transformer current capacity commensurate with line being tested, (f)
Output impedance 5 Ω or less for 0,15 μs and 1 Ω or less for 10μs transient, (g)
External synchronization and triggering capability. 2.
Oscilloscope with 10 MHz bandwidth or greater. 3.
Differential high‐voltage probe. 4.
Isolation transformer. 5.
5 Ω resistor power metal film resistor with inductance lower 100 nH and peak power capability. 6.
LISN defined in 5.2.4, with added inductor for a total inductance not less than 20 μH for parallel injection. 5.4.9.3
a.
Test equipment
Setup
The test setup shall be as follows: 1.
Maintain a basic test setup for the EUT as specified in 5.2.6 and Figure 5‐3. 2.
For calibration: (a)
Configure the test equipment in accordance with Figure 5‐21 for verification of the waveform. (b)
Set up the oscilloscope to monitor the voltage across the 5 Ω resistor. (c)
For EUT testing configure the test equipment as shown in Figure 5‐22 (series test method) or Figure 5‐23 (parallel test method). 61 ECSS‐E‐ST‐20‐07C 31 July 2008 NOTE 1 With series injection, the internal LISN capacitor at the input power side is protecting the source. NOTE 2 With parallel injection, the internal inductance is protecting the source, so a minimum value is needed as specified in 5.4.9.2a.6. Spike generator Series or parallel output 5 Ω resistor Oscilloscope Differential probe Data recorder Figure 5‐21: CS of power leads, transients, calibration set‐up Stimulation and monitoring of EUT Spike generator
Series output EUT LISN Power inputs Oscilloscope Differential probe Data recorder Figure 5‐22: CS of power leads, spike series injection test setup 62 ECSS‐E‐ST‐20‐07C 31 July 2008 Stimulation and monitoring of EUT Spike generator
Parallel output Inductors EUT LISN Power inputs Oscilloscope Differential probe Data recorder Figure 5‐23: CS of power leads, spike parallel injection test setup 5.4.9.4
a.
Procedures
The test procedures shall be as follows: 1.
Turn on the measurement equipment and wait until it is stabilized. 2.
Perform the following procedure using the calibration setup: 3.
(a)
Adjust the pulse generator for the pulse width, and pulse repetition rate. (b)
Adjust the amplitude of the signal to the level specified in associated limit. (c)
Verify that the waveform complies with the requirements, if not, correct accordingly. (d)
Record the pulse generator amplitude setting. Test the EUT by performing the following procedure using the test setup: (a)
Turn on the EUT and wait until it is stabilized. (b)
Adjust the spike generator to a pulse duration. (c)
Apply the test signal to each power lead and increase the generator output level to provide the specified voltage without exceeding the pulsed amplitude setting recorded during calibration. (d)
Apply repetitive (6 to 10 pulses per second) positive spikes to the EUT ungrounded input lines for a period not less than 2 minutes in duration, and if the equipment employ gated circuitry, trigger the spike to occur within the time frame of the gate. (e)
Repeat 5.4.9.4a.3(d) with negative spikes. (f)
Monitor the EUT for degradation of performance. 63 ECSS‐E‐ST‐20‐07C 31 July 2008 (g)
If susceptibility is noted, determine the threshold level in accordance with 5.2.10.3 and verify that it is above the specified requirements. (h)
Record the peak current as indicated on the oscilloscope. (i)
Repeat 5.4.9.4a.3(b) through 5.4.9.4a.3(h) on each power lead. 5.4.10
RS, magnetic field, 30 Hz to 100 kHz
5.4.10.1
Purpose
This test procedure is used to verify the ability of the EUT to withstand radiated magnetic fields. 5.4.10.2
a.
Test equipment
The test equipment shall be as follows: 1.
Signal source, 2.
Power amplifier, 3.
Radiating loop having the following specifications: 4.
(a)
Diameter: 12 cm (b)
Number of turns: (c)
Wire: N°12 AWG, insulated copper (d)
Magnetic flux density: 9,5×107 pT/A of applied current at a distance of 5 cm from the plane of the loop. 20 Loop sensor having the following specifications: (a)
Diameter: 4 cm (b)
Number of turns: (c)
Wire: 7‐41 Litz wire (7 strands, N°41 AWG) (d)
Shielding: (e)
Correction Factor: manufacturer’s data for factors to convert measurement receiver readings to decibels above one picotesla (dBpT) 51 electrostatic 5.
Measurement receiver, 6.
Calibration fixture: coaxial transmission line with 50Ω characteristic impedance, coaxial connections on both ends, and space for a current probe around the centre, 7.
Current probe, 8.
LISN. 64 ECSS‐E‐ST‐20‐07C 31 July 2008 5.4.10.3
a.
Setup
The test setup shall be as follows: 1.
Maintain a basic test setup for the EUT as specified in Figure 5‐3 and 5.2.6. 2.
Check the measurement system by configuring the measurement equipment, the radiating loop, and the loop sensor as shown in Figure 5‐24. 3.
Test the EUT by configuring the test setup as shown in Figure 5‐25. Radiating loop Field monitoring loop Current probe Signal source inside jig and power
amplifier
Measurement receiver B Measurement receiver A 5 cm Figure 5‐24: Measurement system check configuration of the radiating system Radiating loop Signal source and
power amplifier EUT 5 cm
Figure 5‐25: Basic test set‐up 65 ECSS‐E‐ST‐20‐07C 31 July 2008 5.4.10.4
Test procedures
a.
The measurement equipment shall be turned on and waited until it is stabilized. b.
The following procedure shall be performed using the calibration setup for verification of levels. c.
1.
Set the signal source to a frequency of 1 kHz and adjust the output to provide a magnetic flux density of 110 dBpT as determined by the reading obtained on measurement receiver A and the relationship given in 5.4.10.2a.3(d). 2.
Measure the voltage output from the loop sensor using measurement receiver B. 3.
Verify that the output on measurement receiver B is within ±3 dB of the expected value based on the antenna factor and record this value. The EUT shall be tested by performing the following procedures for determination of location and level of susceptibility. 1.
Turn on the EUT and wait until it is stabilized. 2.
Select test frequencies as follows: 3.
(a)
Locate the loop sensor 5 cm from the EUT face or electrical interface connector being probed and orient the plane of the loop sensor parallel to the EUT faces and parallel to the axis of connectors. (b)
Supply the loop with such a current to produce magnetic field strengths at least 10 dB greater than the limit specified by application of clause 4.2.8 but not to exceed 15 A (183 dBpT). (c)
Scan the frequency range. (d)
If susceptibility is noted, select no less than three test frequencies per octave at those frequencies where the maximum indications of susceptibility are present. (e)
Reposition the loop successively to a location in each 30 by 30 cm area on each face of the EUT and at each electrical interface connector, and repeat 5.4.10.4c.2(c) and 5.4.10.4c.2(d) to determine locations and frequencies of susceptibility. (f)
From the total frequency data where susceptibility was noted in 5.4.10.4c.2(c) through 5.4.10.4c.2(e), select three frequencies per octave over the frequency range. At each frequency determined in 5.4.10.4c.2(f) apply a current to the radiating loop that corresponds to the specified limit, move the loop to search for possible locations of susceptibility without omitting the locations determined in 5.4.10.4c.2(e) while maintaining the loop 5 cm from the EUT surface or connector, and verify that susceptibility is not present. 66 ECSS‐E‐ST‐20‐07C 31 July 2008 5.4.10.5
a.
Data Presentation
In addition to 5.2.10.4, data presentation shall provide: 1.
Tabular data showing verification of the radiating loop in.5.4.10.4b. 2.
Tabular data, diagrams, or photographs showing the locations and test frequencies determined in.5.4.10.4c.2(e) and 5.4.10.4c.2(f). 5.4.11
RS, electric field, 30 MHz to 18 GHz
5.4.11.1
Purpose
This test procedure is used to verify the ability of the EUT and associated cabling to withstand electric fields. NOTE 5.4.11.2
a.
Additional requirements can apply beyond 18 GHz if SHF or EHF payloads are present. These are beyond the scope of the present standard. Test equipment
The test equipment shall be as follows: 1.
Signal generators, 2.
Power amplifiers, 3.
Receive antennas, (a)
under 1 GHz, not applicable. (b)
1 GHz to 18 GHz, double ridge horn, 24.2 by 13.6 cm opening. NOTE 4.
Above 1 GHz receive antennas may be not used, see 5.4.11.3b.2. Linearly polarized transmit antennas NOTE The following antennas are commonly used: • 30 MHz to 200 MHz, biconical, 137 cm tip to tip, • 200 MHz to 1 GHz, double ridge horn, 69,0 cm by 94,5 cm opening, or log‐periodic, • 1 GHz to 18 GHz, double ridge horn, 24,2 cm by 13,6 cm opening. 5.
Electric field sensors (physically small ‐ electrically short), 6.
Measurement receiver, 7.
Power meter, 8.
Directional coupler, 9.
Attenuator, 10.
Data recording device, 11.
LISN defined in 5.2.4, optional. 67 ECSS‐E‐ST‐20‐07C 31 July 2008 5.4.11.3
a.
Test setup
A basic test setup shall be maintained for the EUT as shown and specified in 5.2.6. and Figure 5‐3. NOTE b.
The LISN can be used. For measurement system check, following sensors shall be used: 1.
electric field sensors from 30 MHz to 1 GHz. 2.
either receive antennas or electric field sensors above 1 GHz. NOTE For the electric sensors and receiving antennas to be used, see 5.4.11.2a.3 and 5.4.11.2a.5. c.
Test equipment shall be configured as specified in Figure 5‐26. d.
The measurement system shall be checked as follows: e.
1.
Place the electric field sensors 1 m from, and directly opposite, the transmit antenna as shown Figure 5‐27 and a minimum of 30 cm above the ground plane, not directly at corners or edges of EUT. 2.
Place the receive antennas prior to placement of the EUT, as shown Figure 5‐28, on a dielectric stand at the position and height above the ground plane where the centre of the EUT will be located. For testing EUT, the transmit antennas shall be placed 1 m from the test setup boundary as follows: 1.
2.
30 MHz to 200 MHz (a)
For test setup boundaries ≤ 3 m (including all enclosures of the EUT and the 2 m of exposed interconnecting and power leads specified in 5.2.6.6.), centre the antenna between the edges of the test setup boundary, ensuring that the interconnecting leads represent the actual platform installation and are shorter than 2 m. (b)
For test setup boundaries > 3 m, use multiple antenna positions (N) at spacings as specified in Figure 5‐27, where the number of antenna positions (N) is determined by dividing the edge‐to‐edge boundary distance (in metres) by 3 and rounding up to an integer. 200 MHz and above, use multiple antenna positions (N) as shown Figure 5‐28, where the number of antenna positions (N) is determined as follows: (a)
For testing from 200 MHz up to 1 GHz, place the antenna in a number of positions such that the entire width of each EUT enclosure and the first 35 cm of cables and leads interfacing with the EUT enclosure are within the 3 dB beamwidth of the antenna (b)
For testing at 1 GHz and above, place the antenna in a number of positions such that the entire width of each EUT enclosure and the first 7 cm of cables and leads interfacing with the EUT enclosure are within the 3 dB beamwidth of the antenna. 68 ECSS‐E‐ST‐20‐07C 31 July 2008 f.
For testing EUT, the placement of electric field sensors shall be maintained as specified in 5.4.11.3d.1. Test setup boundary
Electric field sensor EUT
LISN
3 m
1,5 m Antenna
Shielded enclosure
Signal generator RF amplifier
Electric field sensor display EGSE Figure 5‐26: Test equipment configuration 69 ECSS‐E‐ST‐20‐07C 31 July 2008 Test setup boundary
N electric field sensor positions
Electric field
sensor
Electric field Electric field
Electric field sensor
sensor 1m sensor
sensor
N antenna positions
Antenna x/2 N (m) Electric field
Electric field sensor
Antenna Antenna
x/N (m)
x/N (m)
x(m) = edge‐to‐edge boundary distance
x/2 N (m) Shielded enclosure Figure 5‐27: RS Electric field. Multiple test antenna positions Test setup boundary Signal source Connected for system check
Receive antenna
Transmit antenna Signal source Shielded enclosure RF amplifier Directional coupler Connected for measurement Power meter
Measurement receiver Figure 5‐28: Receive antenna procedure 70 ECSS‐E‐ST‐20‐07C 31 July 2008 5.4.11.4
a.
Test procedures
The measurement equipment and EUT shall be turned on and waited until they are stabilized. NOTE b.
It is important at this point to assess the test area for potential RF hazards and take precautionary steps to assure safety of test personnel and fire avoidance. The measurement system shall be checked and calibrated as follows: 1.
2.
Procedure when using electric field sensors: (a)
Record the amplitude shown on the electric field sensor display unit due to EUT ambient. (b)
Reposition the sensor until the level measured in (a) above is < 10 % of the field strength to be used for testing. Procedure when calibrating with the receive antenna: (a)
Connect a signal generator to the coaxial cable at the receive antenna connection point (antenna removed), set the signal source to an output level of 0 dBm at the highest frequency to be used in the present test setup and tune the measurement receiver to the frequency of the signal source. (b)
Verify that the output indication is within ±3 dB of the applied signal, considering all losses from the generator to the measurement receiver and, if deviations larger than 3 dB are found, locate the source of the error and correct the deficiency before proceeding. (c)
Connect the receive antenna to the coaxial cable as specified in Figure 5‐28, set the signal source to 1 kHz pulse modulation, 50 % duty cycle, establish an electric field at the test frequency by using a transmitting antenna and amplifier, and gradually increase the electric field level until it reaches the limit specified by application of clause 4.2.8. (d)
Scan the test frequency range and record the input power levels to the transmit antenna to maintain the required field. (e)
Repeat procedures 5.4.11.4b.2(a) through 5.4.11.4b.2(d) whenever the test setup is modified or an antenna is changed. NOTE c.
The ground plane tends to short‐circuit horizontally polarized fields, so that more power is needed to achieve the same field value in horizontal polarization as in vertical polarization. The EUT shall be tested as follows: 1.
Procedure when using electric field sensors: (a)
Establish an unmodulated electric field at the test start frequency by using an amplifier and transmit antenna, and 71 ECSS‐E‐ST‐20‐07C 31 July 2008 gradually increase the electric field level until it reaches the limit specified by application of clause 4.2.8. 2.
(b)
Set the signal source to 1 kHz pulse modulation, 50 % duty cycle and apply the modulation. (c)
Repeat the test at all frequency tests while maintaining field strength levels in accordance with the associated limit, and monitor EUT performance for susceptibility effects. Procedure when calibrating with the receive antenna: (a)
Remove the receive antenna and reposition the EUT in conformance with 5.4.11.3e. (b)
Set the signal source to 1 kHz pulse modulation, 50 % duty cycle, establish an electric field at the test start frequency by using an amplifier and transmit antenna, and gradually increase the input power level until it corresponds to the level recorded during the calibration routine. (c)
Repeat the test at all test frequencies while assuring the transmitter input power is adjusted in accordance with the calibration data collected, and constantly monitor the EUT for susceptibility conditions. 3.
If susceptibility is noted, determine the threshold level in accordance with 5.2.10.3. 4.
Perform testing over the frequency range with the transmit antenna vertically polarized, and repeat the testing with the transmit antenna horizontally polarized. NOTE 5.
5.4.11.5
a.
The settings needed to achieve the specified field level in vertical polarization are reused as is for the test in horizontal polarization. Repeat 5.4.11.4c.4 for each transmit antenna position determined in 5.4.11.3e. Data presentation
In addition to 5.2.10.4 , data presentation shall provide: 1.
graphical or tabular data listing (receive antenna procedure only) all calibration data collected to include input power requirements used versus frequency, and results of system check in 5.4.11.4b.2(c) and 5.4.11.4b.2(d). 2.
the correction factors used to adjust sensor output readings for equivalent peak detection of modulated waveforms. 3.
diagrams or photographs showing actual equipment setup and the associated dimensions. 72 ECSS‐E‐ST‐20‐07C 31 July 2008 5.4.12
Susceptibility to electrostatic discharges
5.4.12.1
Overview
The purpose of this test is to determine the existence of susceptibility to electromagnetic effects of electrostatic discharges. 5.4.12.2
a.
Test equipment
The test equipment shall be as follows: 1.
DC high voltage supply or an ESD generator as specified in IEC 61000‐4‐2 (Edition 1.2). NOTE 2.
Use of the ESD generator is less hazardous than use of the DC high voltage supply for test operators. The discharge primary circuit is constituted of: (a)
6 kV spark gap, NOTE 1 An air spark gap or an overvoltage suppressor in a sealed pressurized envelop can be used. NOTE 2 An air spark gap is less stable and has longer rise time. (b)
50 pF capacitance, high‐voltage capacitor with inductance less than 20 nH, (c)
47 Ω damping resistor (high voltage specification), NOTE (d)
10 kΩ resistors (high voltage specification). NOTE 3.
The value can be adjusted at critical damping depending on value of capacitance C and self‐
inductance of the discharge circuit; Choke resistors prevent high‐frequency components of discharge from flowing in uncontrolled paths so the discharge parameters are not dependent on length and position of high‐voltage source wires. Monitoring devices: (a)
Two current probes, 100 A peak capability and more than 100 MHz bandwidth, (b)
One high‐voltage probe, 10 kV range, 1 MHz bandwidth, NOTE (c)
If the probe input impedance is not high enough, it can prevent gap arcing by lowering the available voltage. One two‐channels digital oscilloscope with pretriggering capability. NOTE Typical values are 100 ns pretrigger time, display window in the range 1 μs to 10 μs and resolution better than 4 ns. 73 ECSS‐E‐ST‐20‐07C 31 July 2008 5.4.12.3
a.
Setup
The test setup shall be as follows: 1.
Maintain a basic test setup for the EUT as specified in 5.2.6. and Figure 5‐3. NOTE It is important at this point to assess the test area for potential high‐voltage hazards and take necessary precautionary steps to assure safety of test personnel. 2.
When using an ESD generator as a high‐voltage power supply as shown Figure 5‐30 or Figure 5‐31, it is set in the contact discharge mode. 3.
Connect the high‐voltage electrode to the discharge circuit at the node between the spark gap and the capacitor. 4.
The discharge circuit length is not larger than what is necessary to place in series the 20 cm long coupling wire, the damping resistor, the discharge capacitor, the spark gap and the current probe. NOTE 5.
For calibration the test equipment is configured as shown Figure 5‐30, and meeting following provisions: (a)
the discharge circuit is not coupled to the EUT, (b)
choke resistors are near the capacitor, (c)
the current probe monitoring the primary current from the ESD source is near the damping resistor, at the capacitor side, (d)
the high voltage probe is measuring the voltage across the capacitor, grounded at the damping resistor side. NOTE 6.
It is important to ensure that the discharge loop is as small as possible for achieving the transient pulse duration objective defined in 5.4.12.4a.2(d). The high‐voltage probe is not meant to measure the voltage during the discharge but the voltage reached before discharge Test the EUT by configuring the test equipment as specified in Figure 5‐31 and meeting the following provisions: (a)
the high voltage probe used for calibration is removed, (b)
the EUT is mounted on a conductive ground plane using the space vehicle mount and attach points, and operated using the actual electrical harness, or an EMC test harness of identical construction to the actual harness. NOTE It is preferable to use the actual electrical harness. 74 ECSS‐E‐ST‐20‐07C 31 July 2008 (c)
the discharge circuit is supported 5 cm above the ground plane by a non‐conductive standoff with high‐voltage insulation capability, (d)
from calibration, the discharge circuit is kept unchanged in size and shape, and tightly electromagnetically coupled 20 cm along an EUT bundle, held by dielectric bonds NOTE 3 A maximum separation distance of 1 cm between the injection wire and the outer circumference of the bundle under test is a condition for achieving a tight electromagnetic coupling. (e)
a current probe is monitoring the primary current from the ESD source near the damping resistor, (f)
a current probe is monitoring the current in the EUT harness, 5 cm from the EUT connector. 3 3
7
6 2
1 1: EUT 2: EUT or EGSE 3: Access panel 4: Interconnecting cable 5: Non‐conductive standoff 6: Grounding plane 7: HV source 4 5 5 cm
Figure 5‐29: Spacecraft charging ESD susceptibility test 75 ECSS‐E‐ST‐20‐07C 31 July 2008 Injection wire
Spark gap Damping resistor High‐voltage capacitor Current probe Choke resistor Choke resistor High‐voltage probe
ESD sparker or high‐voltage dc power supply Figure 5‐30: Susceptibility to ESD: calibration configuration 20cm coupling Current probe Bundle under test Spark gap
Choke resistor Injection wire tightly coupled to the bundle under test High‐voltage capacitor Damping resistor Current probe Choke resistor ESD sparker or high‐voltage dc power supply Figure 5‐31: Susceptibility to ESD: test equipment configuration 76 ECSS‐E‐ST‐20‐07C 31 July 2008 5.4.12.4
a.
Procedure
The test procedures shall be as follows: 1.
Turn on the measurement equipment and wait until it is stabilized. 2.
Perform a calibration using the calibration setup: (a)
Select the spark gap device or adjust the spark length at the voltage breakdown to be used for the test, (b)
Turn on the high voltage generator, (c)
Using the high voltage probe, check the breakdown voltage value is stable and within ± 30 % from the value to be used for the test. (d)
Monitor the transient current pulse. NOTE 3.
5.4.12.5
a.
A goal is 30 A, 30 ns duration at mid‐height, rise time as short as possible. Means for minimizing the rise time are adjusting the damping resistor, reducing the size loop, checking that both choke resistors are as close as possible to the capacitor, and technology of the spark gap (nature of gas and shape of electrodes). (e)
Record the last current and voltage couple, displayed with a common time reference, (f)
Repeat 5.4.12.4a.2(d) and 5.4.12.4a.2(e) with opposite polarity. Test the EUT as follows: (a)
Fully power the unit during the complete ESD test, (b)
Turn on the high voltage generator, (c)
Establish a pulse discharge at a pulse rate of 1 Hz, with a pulse direction of at least 15 positive and 15 negative, (d)
Record the last primary and secondary current couple, displayed with a common time reference, (e)
Repeat 5.4.12.4a.3(c) and 5.4.12.4a.3(d) on each bundle interfacing with each electrical connector. Data presentation
Superseding clause 5.2.10.4, data presentation shall be as follows: 1.
Provide tables showing statements of compliance with the requirement and the induced current level for each interface connector. 2.
Provide oscilloscope records taken during calibration and EUT testing procedures. 3.
The requirement of 5.2.10.3 does not apply. 77 ECSS‐E‐ST‐20‐07C 31 July 2008 Annex A (informative)
Subsystem and equipment limits
A.1
Overview
There is no single method for achieving EMC. •
Low susceptible equipment is for telecommunication spacecraft flying in a severe EMI environment due to on board large power and possible residual ESD. •
Low emission equipment is for scientific spacecraft for preserving high sensitivity of detectors. Therefore, it is not possible to define a same set of limits for all equipments of all spacecraft and launchers. The EMCCP is the vehicle for tailoring limits and test methods. However, it is a legitimate demand of equipment supplier to ask for EMI limits outside the frame of a specific project. Conducted and radiated emission limits and susceptibility limits defined hereafter are recommended for space projects. A.2
CE on power leads, differential mode,
30 Hz to 100 MHz
In differential mode, on each independent power bus, conducted emissions on power leads, induced by loads, can be limited in the frequency domain under following conditions: •
limits are in the range extending from 30 Hz to 100 MHz, •
a maximum INB in units of dB referenced to 1 μA is a function of frequency defined on Figure A‐1, •
in the low frequency range the limit ICE in units of dB referenced to 1 μA (dBμA) is function of the consumption Idc (in amperes) of the equipment on the line, see Figure A‐2: Idc<1 A ICE = 80 1 A<Idc<100 A I = 80 + 20 log10(Idc) Idc>100 A I = 120 The mode is called “differential” because measurement are done separately on hot and return wires, however it comprises common mode components. “Independent” means connected to separate power sources. 78 ECSS‐E‐ST‐20‐07C 31 July 2008 130
100 Adc
110
30 Adc
100
10 Adc
90
3 Adc
80
1 Adc
Current lim it (dBµA)
120
70
60
50
40
30
20
10
0
10
100
1 000
10 000
100 000
1 000 000
10 000 000
100 000 000
Frequency (Hz)
Figure A‐1: Power leads, conducted emission 90
80
Current limit (dBµA)
70
60
50
40
30
20
10
0
100 000
1 000 000
10 000 000
100 000 000
Frequency (Hz)
Figure A‐2: Common mode conducted emission 79 ECSS‐E‐ST‐20‐07C 31 July 2008 A.3
CE on power leads, in-rush currents
The inrush current of an equipment on the power lines can be limited in the time domain with following characteristics in order to limit the voltage transients on the power bus: •
During any nominal change of configuration, the rate of change of current is limited to 5×104 A/s. •
At switching ON the rate of change of current is lower than 2×106 A/s, absolute value of rise and fall slopes. Specific requirements are usually defined for pulsed radars, plasma thrusters power units. Limits can also be specified for the following characteristics in order to achieve compatibility with the upstream protections of the spacecraft power subsystem. inrush current duration (in ms); •
total charge (in mC); •
inrush current slope (in A/μs). CE on power and signal leads, common mode,
100 kHz to 100 MHz
The conducted emissions on bundles in common mode can be limited with following characteristics: •
limits are in the range extending from 100 kHz to 100 MHz, •
ICE in units of dB referenced to 1 μA (dBμA) is lower than the curve of Figure A‐3, •
the same limit is defined for all cables taken together or bundle per bundle. 100
90
E-field (dBµV/m)
A.4
•
80
70
60
50
40
1.E+07
1.E+08
1.E+09
1.E+10
1.E+11
Frequency (Hz)
Figure A‐3: Radiated electric field limit 80 ECSS‐E‐ST‐20‐07C 31 July 2008 A.5
CE on antenna ports
Spurious conducted emissions on antenna ports can be limited to following values: •
receivers 34 dBμV, •
transmitters (stand‐by mode): 34 dBμV, •
transmitters (transmit mode): ⎯
harmonics, except the second and third, and all spurious emissions: 80dB down the level at the fundamental, ⎯
the second and third harmonics 50 +10 log P (where P is the peak power output) or 80 dB whichever is less. Equipment with antennas permanently mounted are not in the scope of this clause. A.6
DC magnetic field emission
A.6.1
General
The DC magnetic field emission generated by subsystems, equipment and elementary components is limited or characterized for following purposes: •
for establishing the magnetic momentum of the whole space vehicle, •
for establishing the composite DC magnetic field at critical locations. The components of the magnetic emission are DC current loops, solenoids, the permanent field of hard magnetic materials (magnets) and the induced magnetic moment by the Earth‐field on soft magnetic materials, including hysteresis. A.6.2
Characterization
Following parameters of magnetic properties can be determined or characterized: •
permanent induction parameters of operating EUT by determination of magnetic induction B in units of μT under magnetic zero‐field condition, •
induced parameters of not operating EUT by determination of magnetic induction B in units of μT when immerged in a uniform controlled field of 30 μT (calibrated in absence of EUT) in each of 3 rectangular semi‐axes, in both directions, •
determination of the DC magnetic field emission is performed by either measurement or similarity, •
determination by similarity is applied to equipment or subsystems coming from other programs, where re‐use as it is or re‐use with only little modification. 81 ECSS‐E‐ST‐20‐07C 31 July 2008 •
assessment of the dipole model by measurement of magnetic induction B at least at two different distances r and comparing respective products r3(m) B(μT), NOTE •
Distances in the range 0,5 m to 1,5 m can be used. magnitude of the magnetic dipole, (when the equipment is assimilated to a dipole) either: ⎯
by its magnetic moment, or ⎯
by the magnetic induction at some distance of reference. When the unit is assimilated to a dipole, the inverse cube law dependence with distance applies, the following relation (worst case) is used for the equivalence between the magnetic moment and the induction at the distance d: B(T) = 2,10 – 7 M(Am2) / d(m3). •
characterization of the magnetic source when the dipole approximation is inadequate, either by: ⎯
a multiple moment model, or ⎯
a spherical harmonics model, or ⎯
the magnetic induction at the distance of measurement. The distance of reference is specified by the EMCAB in function of the size of the space vehicle or of the actual distance between magnetic sources and susceptible equipment. The magnetic induction is a rough indication that can be sufficient for some applications. The multiple‐moment model or the spherical harmonics model is a precise determination sometimes needed for sensitive payloads. Specific characterization methods are implemented for the multiple‐moment model or the spherical harmonics identification. A.6.3
Limit
The DC magnetic emission of subsystems or equipments can be limited at a level of 0,2 μT at a distance of 1m from any face of the equipment. This limit corresponds to dipole‐like equipment with a magnetic moment of 1 Am2. The limitation is achieved through a combination of techniques: current loop area minimization and coaxial or twisted cables use, non‐magnetic material use, magnetic shields use, compensation techniques with magnets. 82 ECSS‐E‐ST‐20‐07C 31 July 2008 A.7
RE, low-frequency magnetic field
From a few hertz to 50 kHz, the magnetic‐field radiated emissions can be measured. Measurement can be performed at several distances for characterizing the accuracy of a dipole model. If the EUT can be assimilated to a magnetic dipole, emission limits are expressed by its magnetic dipole momentum. No limit is defined at equipment level. The measurement is only for characterization and useful to verify compliance at system level through analysis. Techniques for fulfilling EMC requirement at system level are an appropriate grounding network, magnetic shields, an optimized location of equipments on the space vehicle. A.8
RE, low-frequency electric field
From a few hertz to 30 MHz frequency range the electric‐field radiated emissions of units can be measured. The frequency limits are determined by the EMCAB from payload specifications. The electric field emission from the equipment is expressed in units of dB above 1 μV/m at a distance of 1 m. Measurements at several distances are performed for characterizing the decay law. No limit is defined at equipment level. The measurement is only for characterization and useful to verify compliance with system level requirements through analysis. Techniques for fulfilling EMC requirement at system level are reduction of common mode conducted emission from bundles, and electric shields or appropriate location of equipments on the space vehicle. A.9
RE, electric field, 30 MHz to 18 GHz
In the 30 MHz to 18 GHz frequency range, electric‐field radiated‐emissions from equipment and subsystem including interconnecting cables can be limited under following conditions: •
•
the limit applies to: ⎯
non‐RF equipment, ⎯
RF equipment connected to passive loads or EGSE, in nominal mode, at nominal power, the limit is defined by the curve on Figure A‐4, 83 ECSS‐E‐ST‐20‐07C 31 July 2008 •
the limit is for both horizontally and vertically polarized fields, •
the limit comprises notching lines for launchers or spacecraft receiving bands not represented on Figure A‐4. Additional requirements can apply beyond 18 GHz if SHF or EHF payloads are present. These are beyond the scope of the present standard. For equipment having all internal rise times longer than 35 ns, the specified upper frequency limit can be reduced to 1 GHz. For non‐RF equipment if the emission is lower than 20 dB below the requirement between 500 MHz and 1 GHz the specified upper limit can be reduced to 1 GHz, with the exception of notches above 1 GHz, still to be tested. 1,2
Voltage (Vrms)
1
0,8
0,6
0,4
0,2
0
10
100
1 000
10 000
100 000
1 000 000
Frequency (Hz)
Figure A‐4: Conducted susceptibility limit, frequency domain A.10 CS, power leads, differential mode, 30 Hz to 100 kHz.
The following levels, known to be achievable and already specified in other standards or project specifications, are proposed for the susceptibility test on the power leads specified in clause 5.4.6.4. •
the injected voltage level is equal or larger than the level shown on Figure A‐5, •
a limitation of the injected current before the specified voltage is reached is applied: ⎯
the limit of current is 1 Arms ⎯
the voltage level when the current limit is reached is measured and reported. 84 ECSS‐E‐ST‐20‐07C 31 July 2008 The current applied is reported. Independent power lines are tested separately. NOTE Independent means “connected to separate power sources”. Except in the case of structure return, for each power line, hot and return wires are tested separately. NOTE In case of structure return, the test is only applied to hot wires. The test signal covers the [30 Hz‐100 kHz] frequency range. A.11 CS, power and signal leads, common mode, 50 kHz to
100 MHz
The following levels, known to be achievable and already specified in other standards or project specifications, are proposed for the susceptibility test on the power and signal leads specified in clause 5.4.7.4: •
the common mode level of 3 volts peak to peak or larger is applied, •
the limit of the current induced on the bundle is 3 A peak‐to‐peak, •
the test signal is pulse modulated, NOTE •
Square wave modulation is a particular case of pulse modulation. the duty cycle is depending on the carrier frequency, according to Table A‐1. The same level is applied to all cables together or to bundles taken separately. The common mode induced current on the bundle is reported. The test signal covers the [50 kHz‐100 MHz] frequency range. Table A‐1: Equipment: susceptibility to conducted interference, test signal Frequency range Pulse repetition frequency Duty cycle 50 kHz‐1 MHz 1 kHz 50 % (squarewave) 1 MHz‐10 MHz 100 kHz 20 % 10 MHz‐100 MHz 100 kHz 5 % A.12 CS, power leads, short spike transients
The following levels, known to be achievable and already specified in other standards or project specifications, are proposed for the transient susceptibility test on the power lines specified in clause 5.4.9: •
a series of positive spikes, then a series of opposite spikes superposed on the power voltage shall be applied, 85 ECSS‐E‐ST‐20‐07C 31 July 2008 •
at any time step, the voltage spike amplitude is: ⎯
+100 % or ‐100 % of the actual line voltage if the nominal bus voltage is lower than 100 V, Figure A‐5. ⎯
+50 % or ‐100 % of the actual line voltage if the nominal bus voltage is equal or larger than 100 V Level 0 on Figure A‐5 represents the DC bus voltage. Only the positive spike is represented on Figure A‐5. When a negative spike is applied, the absolute instantaneous transient voltage goes down to 0, never negative. •
tests are performed with two spike durations, the first zero‐crossing is at T=150 ns and at T=10 μs. Independent power lines are tested separately. Independent means “connected to separate power sources”. 120
Percentage of line voltage
100
80
60
40
20
0
0
0,5
1
1,5
2
2,5
3
3,5
4
4,5
-20
-40
-60
Normalized time (in units of T=150ns or T=10µs)
Figure A‐5: CS, voltage spike in percentage of test bus voltage A.13 RS, magnetic field, 30 Hz to 100 kHz
The following levels, known to be achievable and already specified in other standards or project specifications, are proposed for the radiated susceptibility test, magnetic field, specified in clause 5.4.9.4: •
the amplitude of the test signal is equal to or larger than the level on Figure A‐6, •
the source is located at 5 cm of any face of the EUT. The signal test covers the [30 Hz‐100 kHz] frequency range. 86 ECSS‐E‐ST‐20‐07C 31 July 2008 190
180
Limit level (dBpT)
170
160
150
140
130
120
110
100
10
100
1 000
10 000
100 000
Frequency (Hz)
Figure A‐6: Radiated susceptibility limit A.14 RS, electric field, 30 MHz to 18 GHz
The following levels, known to be achievable and already specified in other standards or project specifications, are proposed for radiated susceptibility test, electric field, specified in clause 5.4.10.4: •
the amplitude of the test signal is: ⎯
equipment in the vicinity of beams, outside of the main frame considered as a Faraday cage: 10 V/m, ⎯
An electric field of more than 10 V/m is applied if RF analysis demonstrates that the expected electric field seen in flight by the equipment is larger, ⎯
equipment far from main lobes and secondary lobes, outside of the main frame: 1 V/m, ⎯
equipment inside the main frame: 1 V/m. At RF transmit frequencies, the RS level should be tailored up; at RF receive frequencies, the RS level should be tailored down for receivers. •
an AM or PAM test signal is used, •
both horizontally and vertically polarized fields are used, •
circular‐polarized fields are not used. The signal test covers the [30 MHz‐18 GHz] frequency range. Additional requirements can apply beyond 18 GHz if SHF or EHF payloads are present. These are beyond the scope of the present standard. 87 ECSS‐E‐ST‐20‐07C 31 July 2008 A.15 Susceptibility to electrostatic discharge
The following dispositions, known to be achievable and already specified in other standards or project specifications, are proposed for the ESD test specified in clause 5.4.11.4. The test is performed on following equipment, including or not digital circuits: •
units comprising high‐voltage power sources, •
units man‐handled during normal operation, This condition applies to manned‐flight, For man‐handled equipment, an ESD test by the contact discharge method as defined in IEC‐61000‐4‐2, is more appropriated, •
units outside the main frame of the space vehicle designed as a Faraday cage, •
units connected to sensors, actuators, or other units located outside the main frame designed as a Faraday cage with the exception of the solar array power bus. Specific tests defined in ECSS‐E‐ST‐33‐11 are applied to EEDʹs. Test of models expected to be or to become flight models is not performed. ESD testing can cause latent failures of test article. 88 ECSS‐E‐ST‐20‐07C 31 July 2008 Bibliography
ECSS‐S‐ST‐00 ECSS system – Description ,implementattion and general requirements MIL‐STD‐461E Requirements for the control of electromagnetic interference, characteristics of subsystems and equipment, 20 August 1999; Department of Defence, USA. 89 
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