1、BSI Standards PublicationWB11885_BSI_StandardCovs_2013_AW.indd 1 15/05/2013 15:06Space environment (natural and artificial) Plasma environments for generation of worst case electrical potential differences for spacecraftBS ISO 19923:2017 ISO 2017Space environment (natural and artificial) Plasma envi
2、ronments for generation of worst case electrical potential differences for spacecraftEnvironnement spatial (naturel et artificiel) Environnements plasmatiques pour la gnration de diffrences de potentiel lectrique les plus dfavorables pour les vhicules spatiauxINTERNATIONAL STANDARDISO19923First edit
3、ion2017-06Reference numberISO 19923:2017(E)National forewordThis British Standard is the UK implementation of ISO 19923:2017.The UK participation in its preparation was entrusted to Technical Committee ACE/68, Space systems and operations.A list of organizations represented on this committee can be
4、obtained on request to its secretary.This publication does not purport to include all the necessary provisions of a contract. Users are responsible for its correct application. The British Standards Institution 2017 Published by BSI Standards Limited 2017ISBN 978 0 580 87689 9ICS 49.140Compliance wi
5、th a British Standard cannot confer immunity from legal obligations. This British Standard was published under the authority of the Standards Policy and Strategy Committee on 30 June 2017.Amendments/corrigenda issued since publicationDate Text affectedBRITISH STANDARDBS ISO 19923:2017 ISO 2017Space
6、environment (natural and artificial) Plasma environments for generation of worst case electrical potential differences for spacecraftEnvironnement spatial (naturel et artificiel) Environnements plasmatiques pour la gnration de diffrences de potentiel lectrique les plus dfavorables pour les vhicules
7、spatiauxINTERNATIONAL STANDARDISO19923First edition2017-06Reference numberISO 19923:2017(E)BS ISO 19923:2017ISO 19923:2017(E)ii ISO 2017 All rights reservedCOPYRIGHT PROTECTED DOCUMENT ISO 2017, Published in SwitzerlandAll rights reserved. Unless otherwise specified, no part of this publication may
8、be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address below or ISOs member body in the country of the r
9、equester.ISO copyright officeCh. de Blandonnet 8 CP 401CH-1214 Vernier, Geneva, SwitzerlandTel. +41 22 749 01 11Fax +41 22 749 09 47copyrightiso.orgwww.iso.orgBS ISO 19923:2017ISO 19923:2017(E)Foreword iv1 Scope . 12 Normative references 13 Terms and definitions . 14 Symbols and abbreviated terms .
10、25 Criteria for worst-case environment . 26 Procedures for application to spacecraft design 27 Space environments for worst-case simulations 37.1 GEO worst-case environment. 37.2 PEO and MEO worst-case environments 3Annex A (informative) Spacecraft charging analysis tools. 4Annex B (informative) Rou
11、nd-robin simulation75Annex C (normative) Material properties 10Annex D (informative) Tailoring guideline for this document .13Bibliography .14 ISO 2017 All rights reserved iiiContents PageBS ISO 19923:2017ISO 19923:2017(E)ForewordISO (the International Organization for Standardization) is a worldwid
12、e 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 committee has been established has the right to be represented on that
13、 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 electrotechnical standardization.The procedures used to develop this docume
14、nt and those intended for its further maintenance are described in the ISO/IEC Directives, Part 1. In particular the different approval criteria needed for the different types of ISO documents should be noted. This document was drafted in accordance with the editorial rules of the ISO/IEC Directives
15、, Part 2 (see www .iso .org/ directives).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 identifying any or all such patent rights. Details of any patent rights identified during the developme
16、nt of the document will be in the Introduction and/or on the ISO list of patent declarations received (see www .iso .org/ patents).Any trade name used in this document is information given for the convenience of users and does not constitute an endorsement.For an explanation on the voluntary nature
17、of standards, the meaning of ISO specific terms and expressions related to conformity assessment, as well as information about ISOs adherence to the World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT) see the following URL: www .iso .org/ iso/ foreword .html.This docum
18、ent was prepared by Technical Committee ISO/TC 20, Aircraft and space vehicles, Subcommittee SC 14, Space systems and operations.iv ISO 2017 All rights reservedBS ISO 19923:2017INTERNATIONAL STANDARD ISO 19923:2017(E)Space environment (natural and artificial) Plasma environments for generation of wo
19、rst case electrical potential differences for spacecraft1 ScopeThis document specifies space plasma environments that lead to the generation of the worst-case surface potential differences for spacecraft. It also specifies how to estimate worst-case potential differences by using the simulation code
20、s provided.This document includes plasma energy and density in GEO, PEO, and MEO. This document does not include descriptions of plasma energy and density in LEO because large surface charging in LEO is likely to be due to high-voltage power generation by instrumentation of the spacecraft.This docum
21、ent deals with external surface charging of spacecraft only.2 Normative referencesThere are no normative references in this document.3 Terms and definitionsFor the purposes of this document, the following terms and definitions apply.ISO and IEC maintain terminological databases for use in standardiz
22、ation at the following addresses: IEC Electropedia: available at h t t p :/ www .electropedia .org/ ISO Online browsing platform: available at h t t p :/ www .iso .org/ obp3.1double Maxwellian distributionelectron and proton distribution functions in GEO fitted with two temperaturesNote 1 to entry:
23、Maxwellian distribution is as follows12:fvm nkTmvkTnkT()()()=+22321132212232p/expexxp mvkT222wherem is the mass of particle;k is the Boltzmann constant 1,380 648 52 1023J/K;n1, n2are the number density of particle;T1, T2are the temperature of particle.3.2differential voltagedifferential potentialpot
24、ential difference between any two points in spacecraft, especially the insulator surface and the spacecraft body, during differential charging ISO 2017 All rights reserved 1BS ISO 19923:2017ISO 19923:2017(E)3.3inverted potential gradientresult of differential charging where the insulating surface or
25、 dielectric reaches a positive potential with respect to the neighbouring conducting surface or metal: PDNM (positive dielectric negative metal)3.4normal potential gradientresult of differential charging where the insulating surface or dielectric reaches a negative potential with respect to the neig
26、hbouring conducting surface or metal: NDPM (negative dielectric positive metal)3.5surface chargingdeposition onto or the removal of electrical charges from external surfaces of the spacecraft4 Symbols and abbreviated termseV electron volt, where 1 eV = 1,602 1019JGEO geosynchronous orbitLEO low Eart
27、h orbitMEO medium Earth orbitPEO polar Earth orbitNe electron densityNi ion densityTe electron temperatureTi ion temperature5 Criteria for worst-case environmentThe worst-case environment shall be defined as the space environment measured in space that causes the maximum potential difference between
28、 the spacecraft electrical grounding body and external non-conductive surfaces or isolated conductive surfaces. Worst-case conditions shall be realistic.Combinations of densities and temperatures for a valid worst-case condition shall be subject to all of the following: reported in the literature or
29、 published databases; checked to make sure they are based on valid measurements; physically realistic (i.e. do not violate energy density or other physical requirements); and verified using good spacecraft charging codes (i.e. COULOMB-2, MUSCAT, SPIS, NASCAP-2k).This document is a part of spacecraft
30、 charging design.6 Procedures for application to spacecraft designSpacecraft charging simulation should be carried out at an early stage of spacecraft design. Ideally, this should be before selecting the materials for those spacecraft surfaces that will be exposed to the space environment.2 ISO 2017
31、 All rights reservedBS ISO 19923:2017ISO 19923:2017(E)Use worst-case environments mentioned in Clause 7 as input parameters for charging simulations.Material properties for spacecraft charging can change after exposure to the space environment. If possible, employ simulation tools using material pro
32、perties after the appropriate space environmental ageing. See Annex C.Radiation induced conductivity can change the bulk resistivity of materials. If possible, employ simulation tools that use the material properties after exposure and ageing in the appropriate space environment 11.In the computer s
33、imulations, use the appropriate spacecraft geometry, material data, and environmental conditions. Run the simulation from a zero charging initial condition until differential potentials fully develop.For examples of simulation codes, see Annex A. Note, however, that the list of codes in Annex A is n
34、ot exclusive.7 Space environments for worst-case simulations7.1 GEO worst-case environmentThe double Maxwellian distribution contained in Table 1 shall be used for worst-case simulation.Table 1 Space environment cases simulatedNe1 m3Te1 eVNe2 m3Te2 eVNi1 m3Ti1 eVNi2 m3Ti2 eV2,00E+05 400 2,30E+06 24
35、800 1,60E+06 300 1,30E+06 28 200Other worst cases have been proposed. See Annex B for comparisons. meand miare 9,109 383 56 1031kg and 1,672 621 9 1027kg, respectively.7.2 PEO and MEO worst-case environmentsThe worst-case plasma environment in PEO and MEO will be updated as more published measured e
36、nvironments become available. See Reference 3 for one published PEO environment. ISO 2017 All rights reserved 3BS ISO 19923:2017ISO 19923:2017(E)Annex A (informative) Spacecraft charging analysis toolsA.1 COULOMB-2COULOMB-2 code4can be applied to modelling of spacecraft charging in PEO and GEO. For
37、building of the spacecraft geometrical models and modelling results visualization, the SALOME platform is used. Plasma currents are computed in terms of Langmuir equations and particle trajectory modelling. Integral equation method is used for electrostatic equation solving. Database of electro-phys
38、ical properties of typical spacecraft materials is also included in the code. The code is not easily available outside Russia.A.2 MUSCATMUSCAT5is a fully 3D particle code that can be applied to spacecraft in LEO, PEO and GEO. Its algorithm is a combination of PIC and particle tracking. A parallel co
39、mputation technique is used for fast computation. It has a JAVA-3D based graphical user interface for 3D modelling of spacecraft geometry and output visualization. The surface interactions included in the NASCAP series and SPIS are modelled. A material property database is also included. The code is
40、 commercially available.A.3 NASCAP-2kThe most recent NASCAP code (NASCAP-2k) is available, free, to US citizens only. This is a comprehensive code with realistic geometry. It is reported to combine the capabilities of NASCAP-GEO, NASCAP-LEO and POLAR. The code is not easily available outside the US.
41、A.4 SPISSPIS6is a fully 3D PIC code that allows the exact computation of the sheath structure and the current collected by spacecraft surfaces for very detailed geometries. Surface interactions including photo-electron emission, back-scattering, secondary-electron emission and conduction are modelle
42、d. The source code is freely available from www .spis .org and a mailing list provides a limited amount of support.4 ISO 2017 All rights reservedBS ISO 19923:2017ISO 19923:2017(E)Annex B (informative) Round-robin simulation7B.1 Round-robin simulations with NASCAP-2kIn order to estimate the degree of
43、 charging on spacecraft in GEO charging environments, a generic spacecraft model was constructed. It is shown in Figure B.1. The back sides of the arrays were covered with graphite. Dimensions of the model are the following.The body is X: 1,86 m; Y: 1,55 m; Z: 2,56 m. The NPaint box on the top is X:
44、 0,62 m; Y: 0,516 m; Z: 0,62 m. The aluminium box at the bottom is X: 0,30 m; Y: 1,55 m; Z: 0,62 m. The solar arrays have a width of 2,5 m; length: 4,0 m; thickness: 0,10 m; twist: 45 degrees. The solar array booms are 2,0 m long and 0,10 m square in cross-section. The round antenna is 2,5 m in diam
45、eter and separated from the body by 0,3 m. Material properties are shown in Table B.1.Figure B.1 Calculation model with NASCAP-2k ISO 2017 All rights reserved 5BS ISO 19923:2017ISO 19923:2017(E)Table B.1 Material propertiesCoverglass materialDielec-tric constantThick-ness mBulk conductiv-ity 1m1Atom
46、ic numbermaxEmaxkeVProton yieldProton max eVPhotoemis-sion A m2Surface resistiv-ity /squareAtomic wt amuDensi-ty kg m3Graphite 1 1,00E-03 1 4,5 0,93 0,28 0,455 80 7, 20E-06 1 12,01 2 250Aluminium 1 1,00E-03 1 13 0,97 0,3 0,244 230 4,00E-05 1 26,98 2 699Black Kaptona3,5 2,50E-06 1 5 5,2 0,90 0,455 14
47、0 5,00E-06 1 12,01 1 600Kaptona3,5 1,27E-04 1,00E-16 5 2,1 0,15 0,455 140 2,00E-05 1,00E+16 12,01 1 600Solar cells (MgF2)3,8 1,25E-04 1,00E-13 10 5,8 1 0,244 230 2,00E-05 1,00E+19 20 2 660OSR 4,8 1,50E-04 1,00E-16 10 3,3 0,5 0,455 140 2,00E-05 1,00E+19 20 2 660NPaint 3,5 1,27E-04 1,00E-16 5 2,1 0,15
48、 0,455 140 2,00E-05 1,00E+16 12,01 1 600aKapton is the trade name of a product supplied by DuPont. This information is given for the convenience of users of this document and does not constitute an endorsement by ISO of the product named. Equivalent products may be used if they can be shown to lead
49、to the same results.This model was placed in simulated GEO environments in the NASCAP-2k spacecraft charging code and allowed to charge for 2 000 s of time. The environments used were daylight and eclipse in these proposed worst cases.The electron and ion densities and temperatures for these environments are given in Table B.2.Table B.2 Space environment cases simulatedEnvironment nameNe1 m3Te1 eVNe2 m3Te2 eVNi1 m3Ti1 eVNi2 m3Ti2
