1、raising standards worldwideNO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAWBSI Standards PublicationBS ISO 11221:2011Space systems Space solarpanels Spacecraft charginginduced electrostatic dischargetest methodsBS ISO 11221:2011 BRITISH STANDARDNational forewordThis British Sta
2、ndard is the UK implementation of ISO 11221:2011.The UK participation in its preparation was entrusted to TechnicalCommittee ACE/68/-/1, Space systems and operations - Design,Engineering and Production.A list of organizations represented on this committee can beobtained on request to its secretary.T
3、his publication does not purport to include all the necessaryprovisions of a contract. Users are responsible for its correctapplication. BSI 2011ISBN 978 0 580 66381 9ICS 49.140Compliance with a British Standard cannot confer immunity fromlegal obligations.This British Standard was published under t
4、he authority of theStandards Policy and Strategy Committee on 31 August 2011.Amendments issued since publicationDate Text affectedBS ISO 11221:2011Reference numberISO 11221:2011(E)ISO 2011INTERNATIONAL STANDARD ISO11221First edition2011-08-01Space systems Space solar panels Spacecraft charging induc
5、ed electrostatic discharge test methods Systmes spatiaux Panneaux solaires spatiaux Matriaux dessai de dcharge lectrostatique induite par la charge du vaisseau spatial BS ISO 11221:2011ISO 11221:2011(E) COPYRIGHT PROTECTED DOCUMENT ISO 2011 All rights reserved. Unless otherwise specified, no part of
6、 this publication may be reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying and microfilm, without permission in writing from either ISO at the address below or ISOs member body in the country of the requester. ISO copyright office Case postale 56 CH
7、-1211 Geneva 20 Tel. + 41 22 749 01 11 Fax + 41 22 749 09 47 E-mail copyrightiso.org Web www.iso.org Published in Switzerland ii ISO 2011 All rights reservedBS ISO 11221:2011ISO 11221:2011(E) ISO 2011 All rights reserved iiiContents Page Foreword iv 1 Scope 1 2 Terms and definitions . 1 3 Symbols an
8、d abbreviated terms 5 3.1 Symbols 5 3.2 Abbreviated terms . 7 4 Tailoring . 7 5 Test Items . 7 6 Preliminary tests for ESD inception statistics . 10 6.1 Purpose 10 6.2 Test facility . 10 6.3 Test coupon . 10 6.4 External circuit . 10 6.5 Test procedures . 11 6.6 Estimation of number of ESD events in
9、 orbit . 11 7 Qualification test for secondary arc 12 7.1 Purpose 12 7.2 Triggering method and test facility . 12 7.3 External circuit . 12 7.4 CIC gap test Test coupon and procedures 13 7.5 Panel test Test coupon and procedures 13 7.6 Success criteria . 13 8 Characterization tests for robustness to
10、 ESD and plasma interaction . 14 8.1 Power degradation 14 8.2 Secondary arc 15 8.3 Power leakage to plasma 15 8.4 Solar array back surface test . 17 9 Test report 17 Annex A (informative) Plasma interaction and electrostatic discharge effects on solar array 19 Annex B (informative) Secondary arc qua
11、lification processes 22 Annex C (normative) Chamber size for a test using LEO-like plasma 23 Annex D (informative) ESD events analysis . 24 Annex E (informative) Spacecraft charging analysis 27 Annex F (informative) Derivation of theoretical surface flashover current 29 Annex G (normative) External
12、circuit of secondary arc test 31 Annex H (informative) Solar cell I-V characteristics measurement . 36 Annex I (informative) Secondary arc statistics 38 Annex J (informative) Solar array back surface test . 41 Bibliography 42 BS ISO 11221:2011ISO 11221:2011(E) iv ISO 2011 All rights reservedForeword
13、 ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO member bodies). The work of preparing International Standards is normally carried out through ISO technical committees. Each member body interested in a subject for which a technical
14、 committee has been established has the right to be represented on that committee. International organizations, governmental and non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of elec
15、trotechnical standardization. International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2. The main task of technical committees is to prepare International Standards. Draft International Standards adopted by the technical committees are circulated to the
16、 member bodies for voting. Publication as an International Standard requires approval by at least 75 % of the member bodies casting a vote. Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. ISO shall not be held responsible for iden
17、tifying any or all such patent rights. ISO 11221 was prepared by Technical Committee ISO/TC 20, Aircraft and space vehicles, Subcommittee SC 14, Space systems and operations. BS ISO 11221:2011INTERNATIONAL STANDARD ISO 11221:2011(E) ISO 2011 All rights reserved 1Space systems Space solar panels Spac
18、ecraft charging induced electrostatic discharge test methods 1 Scope This International Standard specifies qualification and characterization test methods to simulate plasma interactions and electrostatic discharges on solar array panels in space. This International Standard is applicable to solar a
19、rray panels made of crystalline silicon, gallium arsenide (GaAs) or multi-junction solar cells. This International Standard addresses only surface discharges on solar panels. 2 Terms and definitions For the purposes of this document, the following terms and definitions apply. 2.1 active gap gap betw
20、een solar cells across which a potential difference is present when the solar array power is available 2.2 blow-off emission of negative charges into space due to an electrostatic discharge 2.3 collisionless plasma plasma in which the mean free paths of electron-neutral, ion-neutral and coulomb coll
21、isions are longer than the scale length of interest NOTE Chamber length is an example of a scale length of interest. 2.4 differential charging spacecraft charging where any two points are charged to different potentials 2.5 differential capacitance capacitance between any two points in a spacecraft,
22、 especially between the insulator surface and the spacecraft body 2.6 differential voltage potential difference between any two points in a spacecraft during spacecraft charging, especially between the insulator exterior surface potential and the spacecraft chassis potential 2.7 discharge inception
23、voltage lowest voltage at which discharges of specified magnitude will recur when a DC voltage is applied between any two points in a spacecraft, especially between the insulator surface and the spacecraft body BS ISO 11221:2011ISO 11221:2011(E) 2 ISO 2011 All rights reserved2.8 electrical breakdown
24、 failure of the insulation properties of a dielectric, resulting in a sudden release of charge with possible damage to the dielectric concerned 2.9 electric propulsion spacecraft propulsion system in which the thrust is generated by accelerating charged particles that are neutralized before they are
25、 ejected in order to produce a jet 2.10 electrostatic discharge electrical breakdown of dielectric or gas or vacuum gaps, and also of surface interface of dissimilar materials, caused by differential charging of parts of dielectric materials and their interfaces 2.11 gap distance distance between bi
26、ased cells or conductors 2.12 glow discharge gaseous discharge with a surface glow near the cathode surface NOTE The origin of the ionized gas is mostly ambient neutral gas molecules rather than metal vapour from the cathode surface. 2.13 inverted potential gradient inverted voltage gradient result
27、of differential charging where the insulating surface or dielectric reaches a positive potential with respect to the neighbouring conducting surface or metal NOTE This phenomenon is also known as PDNM (positive dielectric negative metal). 2.14 non-sustained arc passage of current from an external so
28、urce through a conductive path that lasts only while the primary discharge current flows See Figure 1. 2.15 normal potential gradient normal voltage gradient result of differential charging where the insulating surface or dielectric reaches a negative potential with respect to the neighbouring condu
29、cting surface or metal NOTE This phenomenon is also known as NDPM (negative dielectric positive metal). 2.16 permanent sustained arc passage of current from an external source through a conductive path that keeps flowing until the external source is intentionally shut down See Figure 1. NOTE Some pe
30、rmanent sustained arcs may leave a permanent conductive path even after the shut-down. 2.17 Poisson process stochastic process in which events occur independently of one another BS ISO 11221:2011ISO 11221:2011(E) ISO 2011 All rights reserved 32.18 power generation voltage potential difference betwee
31、n the positive and negative terminals of a solar array string 2.19 primary arc trigger arc developed phase of a primary discharge, under an inverted potential gradient, which is associated with cathodic spot formation at a metallic or semiconductor surface 2.20 primary discharge initial electrostati
32、c discharge which, by creating a conductive path, can trigger a secondary arc See Figure 1. NOTE The current can include blow-off current and surface flashover current. 2.21 punch-through dielectric breakdown between two sides of an insulator material 2.22 ram space in front of and adjacent to a spa
33、cecraft in which the plasma density can be enhanced by the motion of the spacecraft 2.23 satellite capacitance absolute capacitance capacitance between a satellite body and the ambient plasma 2.24 secondary arc passage of current from an external source, such as a solar array, through a conductive p
34、ath initially generated by a primary discharge NOTE Figure 1 shows the various stages of a secondary arc. 2.25 snapover phenomenon caused by secondary electron emission that can lead to electron collection on insulating surfaces in an electric field 2.26 solar array front surface solar array surface
35、 where solar cells are laid down NOTE Solar cells are laid down on the side of a solar panel that normally faces the sun. 2.27 solar array back surface solar array surface where solar cells are not laid down NOTE Solar cells are not laid down on the side of a solar panel that normally faces away fro
36、m the sun. 2.28 surface charging deposition of electrical charges onto, or their removal from, external surfaces BS ISO 11221:2011ISO 11221:2011(E) 4 ISO 2011 All rights reserved2.29 surface flashover surface discharge propagating laterally over a dielectric material NOTE Surface flashover is someti
37、mes called a “brushfire discharge”. 2.30 temporary sustained arc passage of current from an external source through a conductive path that lasts longer than a primary discharge current pulse but terminates without leaving a permanent conductive path See Figure 1. 2.31 wake trail of rarefied plasma l
38、eft behind by a moving spacecraft Key 1 primary discharge (blow-off + flashover) 2 non-sustained arc (NSA) 3 temporary sustained arc (TSA) 4 permanent sustained arc (PSA) 5 secondary arc i current Isc short-circuit current of one or more solar array circuits t time The primary discharge is fed by ab
39、solute and differential capacitances. The secondary arc is fed by the solar array power. Figure 1 Stages of secondary arc BS ISO 11221:2011ISO 11221:2011(E) ISO 2011 All rights reserved 53 Symbols and abbreviated terms 3.1 Symbols Asarea of surface of plasma CBCbypass capacitance CCGdifferential cap
40、acitance CGScapacitor representing capacitance between solar panel structure and ambient plasma Ckaptoncapacitor representing capacitance underneath the cells through the Kapton layer Csatsatellite capacitance Cstringcapacitor representing capacitance of solar array string Cvcapacitance per unit are
41、a of coverglass C1capacitor representing capacitance of solar array string and capacitance underneath the cells through the Kapton layer C2capacitor representing capacitance of solar array string and capacitance underneath the cells through the Kapton layer C3capacitor representing capacitance of so
42、lar array string and capacitance underneath the cells through the Kapton layer D1fast switching diode D2fast switching diode D3fast switching diode dshsheath thickness I0reverse saturation-current density, in amperes per square metre (A/m2) I1power supply representing power generated by the solar ar
43、ray Isc short-circuit current of one or more solar array circuits Isectioncurrent of a solar array section Istringcurrent of a solar array string i current j number of bins k Boltzmann constant Lextinductance to form the pulse current shape n diode constant BS ISO 11221:2011ISO 11221:2011(E) 6 ISO 2
44、011 All rights reservedPi probability that an event occurs in the i-th binQ charge q elementary charge R resistance Rextresistance to form the pulse current shape RLresistance to adjust the voltage between two strings under test RsectionUsection/Isectionresistance needed to get the right voltage and
45、 current in the loop simulating the solar panels section RstringUstring/Istringresistance needed to get the right voltage and current across the solar cells simulating the solar array string under arcing test r radius of plasma T temperature, in kelvins (K) Te electron temperature Tiion temperature
46、t time tESDtime to threshold differential voltage U1constant current source U2constant voltage source Usectionvoltage of a solar array section Ustringvoltage of a solar array string Vbpower supply representing charging potential of spacecraft body vpvelocity of plasma wavefront V potential differenc
47、e angle DDebye length eelectron density iion density CGcoverglass potential satsatellite body potential BS ISO 11221:2011ISO 11221:2011(E) ISO 2011 All rights reserved 73.2 Abbreviated terms eV electron volt (1 eV = 1,602 1019J) CIC coverglass interconnect cell ESD electrostatic discharge GEO geosyn
48、chronous orbit IPG inverted potential gradient LEO low Earth orbit NPG normal potential gradient NSA non-sustained arc PA primary arc PEO polar Earth orbit PI plasma interaction PSA permanent sustained arc TSA temporary sustained arc 4 Tailoring Specifications described in this International Standar
49、d are tailorable upon agreement between the customer and the supplier. 5 Test items NOTE Annex A provides an overview of the subject of spacecraft charging and electrostatic discharge (ESD) phenomena for readers who are not familiar with the subject. The aims of the plasma interaction (PI) and ESD tests are to simulate the detrimental phenomena anticipated in space for a given solar array design, to evaluate a designs resistance to the phenomena and to provide data necessary for the judgment of qualificatio
