ÿWPC_  °“Ý;b(¼ªuØ@Ž1èûCÂé½4Ž=}FÇ /Aù‹‘¼ߌÛžÜÙÜ%Ç‚w©‹uCé$~›ú=¬RŠûåFþh¬pÿT‡kè0¯ž»ÍIˆàŽÁ” mXŽ5cŒ&O_HïÞQ¬Ìö m²}6•/"nÿáÈ&Ázoõƒ/Ø;[<©‚9å|A5ÝÁÛ0Ñ(û€RNdåzþ{=?fvYo/‹¸Ÿ"Í^:çÊ´ÊD½T¿m/‹Û'ÕÐÛ3ö·=®Ôć=̼k³yîçsTÿÛ®Råwhkÿ'åe8ƒì3›jÚº6QYgÒÞ釓ƒËvmžrl·"îÙ­EP±"·÷ þ>Xüe´ T?á¬TaUA ÜØA1ÚMeTT`žå•='ˆÉ4ä¶Àuøáx»…F+¹J‘ROˆk3az¡[¼¤”mIEÉIlMcLM­MǺùY¶˜AvÒa¶uì˜s¡rnêË›5—)^We‰‚ù®ä 1EȉdieÇ´Ù¸Ýùk>ªAÜ, õRGlbP¯ZÍ«uÙ1¿Šzöme¶j¶`ŸÍQýñ:¦ÚêóâHíØæ6ÄaÒ ,å Æ'$‹,-]ûüÉ*8UN %^ 0öd@Zw@š4Úîýf #  a , 2 8 > hˆD D D D D D D D D D D D D D D D D D D D D D D D D D D D 0LÌ Ì Ì Ì Ì B%*     B*B (ÖÃ9 Z ‹6Times New Roman RegularX(Î%õ$¡¡ÔUKUS.,ÔÔ..ÔÔ,,ÔÓ  ÓÓ  ÓÓ  ÓÓ  ÓÑTRW\Ï6Á&A4W\Ï6Á&A4Ð6Â&A4Ð6Â&A4TÑÔ"UKú ú úÔc:\wpwin6\template\wpwp60uk.wpt ïðñUòóDôDõÊöÊ÷ÊøÊ`šì 3|xøÔȘQMS 1725 Print SystemPSCRIPT´¨ÀÀÀÀ´¨0 TABLE AÈÈÈH             X›@          –¿À         ÐTABLE A >c$"Small Circleð"ðà0 à&ÿÿ0 d d dÝ ƒ%õ!ÝÔUKUS.,ÔÔ..ÔÔ,,ÔÓ  ÓÓ @ ÓÓ  ÓÓ  ÓÑTRW\Ï6Á&A43Ø'Ð6Â&A4ÿ3Ø'TÑÔ"UKú ú úÔÝ  Ýñåñ›ñåñÔ€&½&XXÔÓK7°‚Xœˆu‚ì` 9 % ¸  ‚ìÖh•X°œXKÓÔ% € Ô€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€à À àà  àà p àà È à€€€€€€€€€€à  à€€€€€€€€€ñåñœñåñSO96.5.01ñåñ›ñåñ€€€€€1Ð ° Ѐ€€€Ô‡Š±Š&&½Ôò òÐ †Ö ÐÓ  Ó€The€Operational€Simulators€of€the€ñåñœñåñISOñåñ›ñåñ€SpacecraftÌ€€Ô#†&½&ŠŠ±;#ÔÔ‡Š±Š&&½ÔÐ Zª Ðó óÔ#†&½&ŠŠ±ë#ÔA.€ñåñœñåñKrogvigñåñ›ñåñÐ X¨ ÐñåñœñåñESAñåñ›ñåñ/ESOC,€Robert€Bosch€Str.€5,Ì€€64293€Darmstadt€Germany.Ô‡Š±Š&&½Ôò òòòÐ  T ÐÓrÓÌÌAbstractÔ#†&½&ŠŠ±É#Ôóóó óÐ Ö &  ÐÌ€ÌAll€together€4€versions€of€the€€ISO€(Infrared€Space€Observatory)€Simulators€with€varying€functionality,Ïperformance€and€usage€have€been€produced:ÌÌà œ à*à ˆ àIPS:à a àà M àThe€ISO€Platform€Simulatorà À àÐ R  Ðà œ à*à ˆ àIHPS:à M àThe€ISO€Hybrid€Platform€Simulatorà  àà p àà È àÐ Ø( Ðà œ à*à ˆ àISIS:à a àà M àThe€ISO€Stand„Alone€Instrument€Simulator€Ð ®þ Ðà œ à*à ˆ àIIIS:à a àà M àThe€ISO€Integrated€Instrument€Simulator€Ð „Ô Ðà œ àà ˆ àà  àà u àÌAfter€an€introduction€on€the€purpose€of€the€project€main€points€in€the€approach€for€its€development€areÏdescribed€from€start€of€the€project€until€date.ÌÌÌò òòòÔ‡Š±Š&&½ÔISO€Mission€BackgroundÔ#†&½&ŠŠ±#Ôó óóóÐ ˆØ ÐÌÌThe€Space€Segment€of€the€ISOñåñ›ñåñ€mission,€the€ñåñœñåñISOñåñ›ñåññåññåñ€satellite,€is€a€space€observatory€in€the€infrared€portion€ofÏthe€spectrum.€The€ñåñœñåñISOñåñ›ñåññåññåñ€satellite€system€is€split€in€a€service€module€and€a€payload€module.€The€serviceÏmodule€provides€the€standard€support€functions€for€the€payload€module.€The€payload€module€comprisesÏa€cryostat€with€four€scientific€instruments€in€the€focal€plane€of€a€ñåñœñåñRitcheyñåñ›ñåñ„ñåñœñåñCretienñåñ›ñåññåññåñ€telescope.€The€ñåñœñåñISOñåñ›ñåññåññåñÏsatellite€was€launched€17.€November€1995.ÌÌà œ à*à ˆ àThe€Launch€and€Early€Orbit€Phase€(ñåñœñåñLEOPñåñ›ñåñ)€was€conducted€from€the€Operations€Control€Centre€Ð 6!†! Ðà œ àà ˆ à(ñåñœñåñOCCñåñ›ñåñ)€at€ñåñœñåñESOCñåñ›ñåñ/ñåñœñåñDarmstadtñåñ›ñåññåññåññåññåñ€€supported€by€a€network€of€Ground€Stations.€Tasks€to€be€accomplished€¼à œ àà ˆ àwas€monitoring,€control€and€commissioning€of€the€spacecraft€and€its€interfaces€to€the€payloads.€The€¼à œ àà ˆ àLEOP€has€terminated€with€handover€of€operations€and€transfer€of€operational€staff€€to€SCC/VILSPA.Ì€Ìà œ à*à ˆ àThe€succeeding€In€Orbit€Phase€ñåñœñåñ(IOP)€ñåñ›ñåñ€is€conducted€ñåñœñåñ€fromñåñ›ñåññåññåñ€Villafranca/Spain€(VILSPA)€in€ñåñœñåñthe€ñåñ›ñåññåññåñ€Ð d%´ & Ðà œ àà ˆ àñåñœñåñcombinedñåñ›ñåññåññåñ€Spacecraft€Control€Centre€(SCC)€and€the€Science€Operations€Centre€(SOC).à Ð àÐ :&Š!' Ðà œ àà ˆ àCommissioning€of€the€payload€scientific€instruments€is€completed.€Current€activities€involve€¼à œ àà ˆ àmonitoring€and€control€of€both€service€and€payload€modules€in€addition€to€support€for€payload€¼à œ àà ˆ àexploitation.Ì€€€ÌDifferent€versions€of€€ISO€satellite€simulators€have€been€developed€to€support€the€various€scope€ofÏactivities€at€ñåñœñåñVILSPA,ñåñ›ñåñ€€ESOC€and€ESTEC.€€ÌÌÌò òòòÔ‡Š±Š&&½ÔSimulators€at€ESOC€for€validation€and€verification€of€the€Control€Centres.Ô#†&½&ŠŠ±'#Ôóóó óÐ À-)0 МñæñÌñæñ›ÌSimulators€of€the€subject€type€are€developed€prior€to€launch€and€€used€to€verify€and€validate€the€GroundÏSegment€functionality€œñíñ€ñíñand›€œñîñ€ñîñreadiness›€œñìñ€ñìñto›€support€LEOP€and€œñïñ€ñïñif›€applicable€to€the€succeeding€IOP.€œOtherñéñ€œñèñ2Ð @1,4 Ð2›ñèññèñÐ @1,4 ÐñèññéññêññèñÐ @1,4 ÐñèññêññëñÐ @1,4 Ð2ÌÌÌñëñsimulators›€cover€other€aspect€€such€as€Ground€Station€verification€and€validation€or€€€the€more€€accurateÌœñçñ€2›Ì›Ìñçñflight›€dynamic€simulations€which€do€not€execute€in€real€time€which€are€not€treated€in€this€paper.€€ÌA€major€goal€is€to€gain€confidence€and€evidence€that€all€preparations€are€adequate€for€the€comingÏoperations€and€that€all€nominal€and€failure€cases€can€be€properly€mastered..ÌÌA€simulator€thus:à 9 à€à % àÐ ` ° Ðà œ à*à ˆ àis€used€to€support€testing€of€the€Control€Centre€software€during€development;Ð 6 †  Ðà œ à*à ˆ àis€used€during€the€final€simulation€campaign€prior€to€launch;€€€€€€€€€à È àÐ  \  Ðà œ à*à ˆ àis€used€for€preparation€and€execution€of€Control€Centre€validation€tests€to:Ð â 2  Ðà œ àà ˆ à„à  àverify€the€Control€Centre€database;Ð ¸  Ðà œ àà ˆ à„à  àverify€that€nominal€and€contingency€flight€operations€procedures€are€in€conformance€with€theÐ ŽÞ  Ðà œ àà ˆ àà  àspecifications€made€by€the€manufacturer;Ìà œ àà ˆ à„à  àvalidate€that€the€nominal€and€contingency€flight€operations€procedures€are€correctly€implemented;Ð :Š  Ðà œ à*à ˆ àprovides€training€to€the€flight€control€team€with€the€purpose€to:Ð `  Ðà œ àà ˆ à„à  àeducate€in€understanding€of€S/C;€à À àÐ æ6 Ðà œ àà ˆ à„à  àfamiliarise€newcomers€with€the€operational€interface€and€thus€enable€fluctuation€of€personnel;Ð ¼  Ѐà œ àà ˆ à„à  àkeep€proficiency€for€seldomly€used€operations€in€contingency€cases;Ð ’â Ðà œ à*€à ˆ àprovides€support€during€LEOP€and€IOP;Ð h¸ Ðà œ à*à ˆ àsupports€post€launch€flight€software€validation€prior€to€on„board€software€maintenance€activities.Ð >Ž ÐÌA€simulator€for€validation€of€€the€Control€Centre€is€required€to€provide€interfaces€as€close€to€reality€asÏpossible€where€it€communicates€with€the€real€spacecraft€via€€Ground€Stations€through€an€x.25€likeÏcommunication€network.€€€Simulators€of€this€type€therefore€include€modelling€of€the€Ground€StationsÏinvolved.€The€Ground€Station€modelling€usually€restricts€itself€to€the€channelling,€decoding€and€encodingÏaspects€for€telemetry€and€telecommands.€Ranging€and€Ground€Station€monitoring€interfaces€are€simplifiedÏto€support€only€the€message€protocol€with€the€OCC€€and€do€not€produce€realistic€data€content.ÌÌÌÌò òòòÔ‡Š±Š&&½ÔISO€Simulator€Project:Ô#†&½&ŠŠ±Ð#Ôó óóóÐ pÀ  ÐÌAll€together€4€versions€of€the€€ISO€Simulators€with€varying€functionality,€performance€and€usage€haveÏbeen€produced:ÌÌà œ à*à ˆ àIPS:à a àà M àThe€ISO€Platform€Simulatorà À àÐ Æ#% Ѐà œ àà ˆ àà  àà u àà a àà M àPre€launch€and€LEOP€support€at€ESOC€à  àà p àà È à(terminated)Ð œ$ì& Ðà œ àà ˆ àà  àà u àà a àà M àPost€launch€support€at€VILSPAà À àà  àà p àà È à(ongoing)Ð r% ' ÐÌà œ à*à ˆ àIHPS:à M àThe€ISO€Hybrid€Platform€Simulatorà  àà p àà È àÐ 'n") Ðà œ àà ˆ àà  àà u àà a àà M àSupport€of€the€final€simulations€campaign€at€ESOC€à È à(terminated)Ð ô'D#* Ðà œ àà ˆ àà  àà u àà a àà M àPost€launch€support€at€VILSPAà À àà  àà p àà È à(ongoing)Ð Ê($+ ÐÌà œ à*à ˆ àISIS:à a àà M àThe€ISO€Stand„Alone€Instrument€Simulator€Ð v*Æ%- Ðà œ à€€€€€€€€€€à a àà M àPre€launch€support€at€VILSPA€and€ESTECà p àà È à(terminated)Ð L+œ&. Ðà œ àà ˆ àà  àà u àà a àà M àPost€launch€support€at€VILSPAà À àà  àà p àà È à(ongoing)Ð ",r'/ ÐÌà œ à*à ˆ àIIIS:à a àà M àThe€ISO€Integrated€Instrument€Simulator€à p àà È àà  àà x àÐ Î-)1 Ðà œ àà ˆ àà  àà u àà a àà M àPre€launch€IOP€support€at€VILSPA€à  àà p àà È à(terminated)Ð ¤.ô)2 ÐÌÌRequirements€for€the€various€simulators€were€driven€by€the€approach€selected€for€the€development€of€theÐ &1v,5 Мñðñà œ àà ˆ àà  àà u àà a àà M àà 9 àà % àà ¸ àà  àà þ àà ê àà Ö àà h àà À àà  àà p àà È àà  àà x à€€€€€€€€€€€€€€€€€€3ñðññññÌññññðññðññññÌññññðñ€ñðñControl›€Centres€and€their€evolving€configurations€requiring€simulator€support.€OCC/SCC€and€SOC€wereÏdeveloped€and€tested€separately,€then€transferred,€integrated€and€tested€at€VILSPA€prior€to€ISO€launch:Ìœñòñ€Ìà œ àà ˆ àà  àà u àà a àà M àà 9 àà % àà ¸ àà  àà þ àà ê àà Ö àà h àà À àà  àà p àà È àà  àà x à€€€€€€€€€€€€€€€€€€3›Ìñòñ›Ìà œ à*à ˆ àThe€Pre„launch€OCC/LEOP€facilities€at€ESOC€and€the€post„launch€SCC€facilities€at€VILSPA€were€Ð Þ. Ðà œ àà ˆ àdeveloped€under€the€responsibility€of€ESOC.€Both€facilities€required€simulator€support€with€largely€¼à œ àà ˆ àthe€same€functionality:€high€fidelity€in€the€area€of€the€platform€subsystems€and€low€fidelity€in€the€¼à œ àà ˆ àpayload€area.€€This€led€to€the€IPS€version.€ÌÌà œ à*à ˆ àThe€Pre„launch€SOC€facilities€at€ESTEC€and€the€post„launch€SOC€facilities€at€VILSPA€were€Ð  \  Ðà œ àà ˆ àdeveloped€under€the€responsibility€of€ESTEC.€The€associated€simulator€functionality€was€driven€¼à œ àà ˆ àby€the€requirements€for€realistic€TM€and€TC€interfaces€to€the€4€payload€subsystems.€This€led€to€the€¼à œ àà ˆ àupgrade€of€IPS€required€for€both€ISIS€and€IIIS€versions.ÌÌà œ à*à ˆ àCommunication€between€SOC€and€S/C€or€Simulator€always€takes€place€via€SCC.€Any€use€of€the€Ð :Š  Ðà œ àà ˆ àISIS€or€IIIS€by€SOC€requires€the€interfaces€between€SOC€and€SCC€to€be€met.€During€pre„launch€Ïà œ àà ˆ àtesting€at€VILSPA€this€was€effected€by€the€operational€SOC/SCC.€This€led€to€the€IIIS€version.ÌÌà œ à*à ˆ àPre„launch€activities€at€ESTEC€took€place€without€access€to€SCC.€€Post„launch€use€of€operational€Ð ’â Ðà œ àà ˆ àfacilities€(SCC)€at€VILSPA€was€prohibited€for€safety€reasons.€The€simulator€thus€required€inclusion€¼à œ àà ˆ àof€relevant€portions€of€the€SCC€functions€(ODS€and€IDCS)€to€be€of€any€use.€This€led€to€the€upgrade€¼à œ àà ˆ àrequired€for€the€ISIS€version.ÌÌà œ à*à ˆ àA€genuine€requirement€for€the€Hybrid€simulator€did€not€exists.€However€it€was€recognised€that€a€Ð À Ðà œ àà ˆ àfacility€which€allowed€execution€of€the€original€on„board€code€had€advantages.€The€IHPS€was€¼à œ àà ˆ àdeveloped€under€a€study€contract.€The€results€also€being€of€value€for€other€projects.ÌÌœñóñÌñóñ›ÌÓ  ÓÔ*wƒ 7 ddd Xdd Xdd X°"°"wÔÔ,ïdd ÔÔ,Ädd ÔÔ,–dd ÔÔ,•dd ÔÔ,Ådd ÔÔ+  ÔÐ €22 î> ……ÐÓ\1ÓÓ  ÓFUNCTIONAL€DIFFERENCES€BETWEEN€THEÏSIMULATOR€VERSIONSÌÓŸ2ÓÐ I€22260þN Jœ‹‹22 ……IÐÓ  ÓSIMULATOR€VERSIONÐ 7€22("R¢! 222 ……7ÐÓ:3ÓÐ *€22yÉ!22 *ÐÓ  ÓIPSÐ 0€22!Ý-" 22 0ÐÓÈ3ÓÓ  ÓIHPSÐ 0€22!Ý-# 22 0ÐÓ4ÓÓ  ÓIIISÐ 4€222!Ý-$ 22 4ÐÓg4ÓÓ  ÓISISÐ 0€22!Ý-% 222 0ÐÓ»4ÓACC€software€modelled€by€reuse€of€original€ADA€source€code€Ð '€27h ¸&22 'ÐyesÐ '€27h ¸'27 'ÐnoÐ '€27h ¸(27 'ÐyesÐ +€272h ¸)27 +ÐyesÐ '€72h ¸*272 'ÐACC€software€machine€code€loaded€and€executed€by€a€HWÏattachment€to€the€Simulator€computer€including€a€1750ÏprocessorÐ '€77~#Î-72 'ЀÌnoÐ '€77¨"ø/77 'ÐÌyesÐ '€77¨"ø177 'ÐÌnoÐ +€772¨"ø377 +ÐÌnoÐ '€72¨"ø5772 'ÐReduced€modelling€of€the€payload€without€modelling€of€theÏinstrument€softwareÐ '€77¾%!772 'ÐyesÐ '€77è$8 877 'ÐyesÐ '€77è$8 977 'ÐnoÐ +€772è$8 :77 +ÐnoÐ '€72è$8 ;772 'ÐPayload€instrument€(8086)€processor€emulators€executing€theÏoriginal€flight€codeÐ '€77þ'N#=72 'ÐnoÐ '€77('x">77 'ÐnoÐ '€77('x"?77 'ÐyesÐ +€772('x"@77 +ÐyesÐ )€722('x"A772 )ÐLimited€modelling€of€the€SCC€(IDCS€and€ODS)€facilities€Ð )€772h)¸$B722 )ÐnoÐ )€772h)¸$C772 )ÐnoÐ )€772h)¸$D772 )ÐnoÐ +€7722h)¸$E772 +ÐyesÐ&h)¸$F  7722 &ÐÓ  ÓÌœñôñÌñôññöñ›ñõñÔ% € Ôñõññöññ÷ññöñÔ% € Ôñöññ÷ññøññ÷ñÔ% € Ôñ÷ññøññøñÔ% € ÔñøñÓ¯:Ó›Ó  ÓÌAll€4€Simulator€versions€are€all€installed€on€DEC€Equipment:ÌÌà œ à*à ˆ àThe€Platform€Simulator€executes€on€a€DEC€VAX€Workstation€under€Open€VMS€Ð Æ-)J Ðà œ à*à ˆ àThe€Hybrid€Simulator€includes€in€addition€a€1750€processor€attached€to€the€Workstation€hosting€Ð œ.ì)K Ðà œ àà ˆ àthe€Simulator€(TASCO€board€and€VME€interface).Ìà œ à*à ˆ àThe€Integrated€Instrument€Simulator€is€installed€on€a€DEC€Alpha€station€and€a€DEC€VAX€à Ð àÐ H0˜+M Ðà œ àà ˆ àWorkstation.€Theà ¸ àDEC€Alpha€station€€is€€needed€€to€meet€€the€increased€performance€required€forÐ 1n,N Ð4à œ àà ˆ àÐ ° ÐÌà œ àà ˆ àemulation€of€the€8086à þ àprocessors€in€the€payload€instruments.€The€DEC€VAX€Workstation€is€Ð \¬ Ðà œ àà ˆ àneeded€as€interface€to€theà ê àIDCS€for€reasons€of€protocol€compatibility€(OSAK€(x.25)€software€not€Ð 2‚ Ðà œ àà ˆ àavailable€on€DEC„AXP).Ìà œ à*à ˆ àThe€Stand€Alone€Instrument€Simulator€has€in€addition€a€further€DEC€VAX€Workstation€used€forÐ Þ. Ðà œ àà ˆ àthe€SOC€applications.ÌÌÌÔ‡Š±Š&&½Ôò òòòImplementation€approachóóó óÐ 6 †  ÐÌÔ#†&½&ŠŠ±O@#ÔÌApplication€of€the€ESA€Software€Engineering€Standards€ESA„PSS„05„0€is€compulsory€to€all€ESA€softwareÏprojects€and€consequently€also€to€simulators.€These€standards€call€for€a€sequentially€phased€developmentÏapproach€with€interface€documents€in€both€technical€and€managerial€domains.ÌÌà œ à*à ˆ àThe€User€Requirements€Document€(URD)€is€defined€by€the€customers€of€the€simulator€in€the€User€Ð b²  Ðà œ àà ˆ àRequirement€Definition€Phase.€€ÌÌà œ à*à ˆ àThe€Software€Requirements€Document€(SRD)€results€from€an€analysis€of€the€URD€and€defines€Ð ä4 Ðà œ àà ˆ àòòò òwható óóó€shall€be€the€simulator€functions€in€terms€of€software.Ð º  ЀÌà œ à*à ˆ àThe€Architectural€Design€Document€(ADD)€builds€on€the€SRD€and€defines€ò òòòhowó óóó€the€SR€can€be€Ð h¸ Ðà œ àà ˆ àmet.ÌÌà œ à*à ˆ àThe€Detailed€Design€Phase€results€in€the€first€deliveries€to€the€customer€which€includes:Ð ì< Ðà œ àà ˆ à„€System€tested€(against€SR)€operational€delivery€to€be€used€for€acceptance€tests;Ìà œ àà ˆ à„€Draft€versions€of€the€Detailed€Design€Document€(DDDs);Ìà œ àà ˆ à„€User€Documentation.ÌÌà œ à*à ˆ àThe€Transfer€Phase€is€intended€for€execution€of€the€acceptance€tests€by€the€customer€which€leads€Ð j Ðà œ àà ˆ àto:€Ìà œ àà ˆ à„€Second€operational€delivery€with€fixes€to€problems€found€during€acceptance€tests;Ìà œ àà ˆ à„€Updated€User€Documents;Ìà œ àà ˆ à„€Updated€DDD(s).Ì€Ìà œ à*à ˆ àOperation€and€Maintenance€Phase€which€usually€are€scheduled€to€start€at€L„12€months.Ð #n$ ÐÌà œ àà ˆ àÌThe€original€overall€timescale€for€IPS€was:Ì„€start€of€SR€Phaseà 9 àafter€final€issue€of€the€URD:à À àJuly€1991;à p àà È à€Ð v&Æ!( Є€end€of€Transfer€Phase:€€€€€€€€€€€€€€€€à Ö àà h àà À àend€1992;Ð L'œ") Є€launch€date:€€€€à 9 àà % àà ¸ àà  àà þ àà ê àà Ö àà h àà À àNovember€1995.Ð "(r#* ÐÌIdentification€for€the€need€of€an€Instrument€Simulator€started€in€Nov€1992.€This€happened€at€a€time€whenÏthe€IPS€was€already€into€the€transfer€phase€but€at€a€time€when€the€launch€date€had€been€postponed.€€ÌStrict€adherence€to€the€sequential€nature€of€phases€were€not€adhered€to€during€the€ISO€simulator€project.ÏOverlaps€between€the€phases€were€applied€as€found€feasible€mostly€to€maintain€efficiency€of€assigned€staff.€Ì€ÌÌThe€ISO€Simulator€Project€had€two€distinct€customers:ÌÌà œ à*à ˆ àThe€ESOC€Operations€Department€(MOD)€who€provided€the€ISO€Platform€Simulator€URD.€The€Ð ~0Î+4 Їà œ àà ˆ àà  àà u àà a àà M àà 9 àà % àà ¸ àà  àà þ àà ê àà Ö àà h àà À àà  àà p àà È àà  àà x àà Ð à€€€€€5ÌÌà œ àà ˆ àsimulator€used€to€fulfill€their€sole€responsibilities€for€the€LEOP€operations€and€their€respons„¼à œ àà ˆ àibilities€for€S/C€operations€during€the€following€IOP.ÌÌà œ à*à ˆ àESTEC€who€provided€the€ISO€Instrument€€Simulator€URD€and€SRD.€The€simulator€used€to€Ð Þ. Ðà œ àà ˆ àfulfill€their€responsibility€for€operations€of€the€4€scientific€instrument€payloads€during€the€IOP.ÌÌDevelopment€of€the€IPS€was€entrusted€to€the€ESOC€Flight€Control€and€Support€Department€(FCSD)€asÏfrom€start€of€the€SR€Phase.€The€IPS/SRD€itself€was€written€in„house€and€with€begin€of€€the€AD€PhaseÏfurther€work€was€contracted€to€the€Marcol€company€(later€CRAY€Systems).€As€from€start€of€the€AD€phaseÏfor€IIIS/ISIS€the€Marcol€company€was€also€contracted€this€work€justified€by€the€fact€that€the€InstrumentÏSimulator€was€an€upgrade€of€the€existing€IPS.ÌÌFCSD€is€working€with€industrial€frame€contracts€based€on€a€competitive€tender€action.€These€frameÏcontracts€cover€simulator€development€and€maintenance€€awarded€for€a€given€period€of€time.€SeparateÏwork€packages€are€then€assigned€subject€to€competitive€bids€or€direct€negotiations.€Work€packages€can€beÏassigned€for€any€phase€of€development€and/or€maintenance.€ÌÌÌò òòòÔ‡Š±Š&&½ÔISO€Platform€Simulator€„€€IPSÔ#†&½&ŠŠ±~Q#Ôóóó óÐ h¸ ÐÌThe€IPS€forms€the€backbone€of€all€the€ISO€Simulators.€IHPS,€IIIS€and€ISIS€can€be€considered€variationsÏof€the€IPS€with€upgradings€and€downgradings€of€implemented€functions.€They€came€into€being€at€a€pointÏin€time€when€the€IPS€had€already€completed€the€development€phase.ÌÌThe€IPS€URD/SRD€calls€for€a€simulator€with:ÌÌà œ à*à ˆ àmodels€of€the€S/C€Platform€subsystems€as€there€are:Ð @ Ðà œ àà ˆ à„à  àTelemetry€Encoder€model;Ð f Ðà œ àà ˆ à„à  àTelecommand€Subsystem€model;Ð ì< Ѐ€à œ àà ˆ à„à  àRadio€Frequency€Subsystem;Ð Â Ðà œ àà ˆ à„à  àData€Handling€Subsystem€Software€model;Ð ˜è  Ðà œ àà ˆ à„à  àData€Handling€Subsystem€Hardware€model;Ð n ¾! Ðà œ àà ˆ à„à  àAttitude€and€Orbit€Control€Subsystem€Hardware€model€with€FSS,€SAS,€ELS,€Gyros€and€QSS€;Ð D!”" Ðà œ àà ˆ à„à  àAttitude€and€Orbit€Control€Subsystem€Software€model;Ð "j# Ðà œ àà ˆ à„à  àReaction€Control€Subsystem€model;Ð ð"@$ Ðà œ àà ˆ à„à  àStar€Tracker€model;Ð Æ#% Ðà œ àà ˆ à„à  àPower€Distribution€model;Ð œ$ì& Ðà œ àà ˆ à„à  àPower€Generation€model;Ð r% ' Ðà œ àà ˆ à„à  àPayload€models;Ð H&˜!( Ðà œ àà ˆ à„à  àThermal€model;Ð 'n") Ðà œ à*à ˆ àreduced€payload€modelling€without€modelling€of€the€instrument€on€board€software€functions;Ð ô'D#* Ðà œ à*à ˆ àa€model€of€the€S/C€dynamical€behaviour€(attitude€and€orbit);Ð Ê($+ Ðà œ à*à ˆ àa€model€of€the€celestial€environment€(earth,€some€planets€and€star€field)€andÐ  )ð$, Ðà œ à*à ˆ àa€model€of€the€Ground€Stations€(Perth,€Kourou€and€Vilspa)€acting€as€the€interface€to€the€IDCS€Ð v*Æ%- Ðà œ àà ˆ àoperations€control€centre.ÌÌThe€SRD€also€included€the€architectural€decision€to€apply€the€ESOC€developed€infrastructure,€the€GeneralÏPurpose€Software€Simulator€Package€(GPSSP).€GPSSP€is€a€Fortran€IV€based€system€including€scheduling,Ïlogging,€user€interface€for€simulator€control€etc.€and€a€set€of€hooks€to€add€the€special€to€project€S/C€models.ÏIn€the€meantime€ESOC€has€developed€a€new€ADA€based€and€object€oriented€infrastructure€SIMSATÏ(Software€Infrastructure€for€Modelling€of€SATellites).€òòÐ P0 +4 ÐóóÐ &1v,5 Ð6ÌÌThe€AD€activities€started€off€with€a€feasibility€study€on€the€optional€methods€for€implementing€theÏfunctions€of€the€Attitude€Control€Computer€(ACC)€and€the€associated€interfaces€to€the€rest€of€the€simulator.ÏThe€option€of€embedding€a€maximum€amount€of€the€actual€ADA€code€was€selected.ÌThe€other€options€were€to€reimplement€the€algorithms€as€defined€by€the€manufacturer€or€to€introduceÏhardware€in€the€loop.€The€first€of€these€alternatives€was€considered€too€costly,€the€second€one€too€risky€forÏlack€of€existing€hardware€installations.€The€idea€of€using€hardware€in€the€loop€was€later€taken€up€as€a€studyÏproject€with€the€ISO€Platform€Simulator€as€a€test€bed.€It€resulted€in€a€the€ISO€Hybrid€Platform€SimulatorÏwhich€proved€very€successful€and€was€used€during€most€of€the€final€simulation€campaign€prior€to€launch.ÌÌIPS€was€planned€to€be€delivered€in€phases€according€to€progress€in€development€and€testing:ÌÌà œ à*à ˆ àED1:à a àEngineering€Delivery€1€functioning€only€as€a€pure€telemetry€source.€This€was€used€for€Ð ŽÞ  Ðà œ àà ˆ àà  àà u àà a àthe€first€data€flow€tests€during€development€of€the€Control€Centre€Software.Ìà œ àà ˆ àà  àà u àà a àPlanned€delivery:€1.€August€1991.à À àà  àActual€delivery:€31.€July€1991.Ð :Š  ЀÌà œ à*à ˆ àED2:à a àEngineering€Delivery€2€with€telecommand€functions€added.€Also€this€delivery€was€used€Ð æ6 Ðà œ àà ˆ àà  àà u àà a àfor€Control€Centre€Software€testing€during€development.€The€delivery€included€a€few€¼à œ àà ˆ àà  àà u àà a àsubsystems€and€allowed€close€loop€testing.Ìà œ àà ˆ àà  àà u àà a àPlanned€delivery:€1.€September€1991.à  à€Actual€delivery:€30.€September€1991.Ð h¸ ÐÌ€à œ à*à ˆ àOD1:à a àOperational€Delivery€1€with€a€subset€of€subsystem€models€implemented:à x àà Ð àÐ d Ðà œ àà ˆ àà  àà u àà a àPlanned€delivery:€1.€February€1992.à  àActual€delivery:€31.€January€1992.Ð ê: ÐÌ€à œ à*à ˆ àOD2:à a àOperational€Delivery€2€includes€all€required€models.€This€system€tested€version€was€used€for€Ð –æ Ðà œ àà ˆ àà  àà u àà a àthe€acceptance€tests€by€the€customer€(MOD).€OD2€took€place€at€the€end€of€the€development€¼à œ àà ˆ àà  àà u àà a àPhase.€Operational€Delivery€2€included€fixes€made€as€a€result€of€the€testing€since€OD1.Ìà œ àà ˆ àà  àà u àà a àPlanned€delivery:€31.€June€1992.à À àà  àActual€delivery:€31.€July€1992.Ð h ÐÌÌAcceptance€tests€took€place€during€the€transfer€phase€and€terminated€with€start€of€the€Maintenance€Phase.€ÌPlanned€duration€was€1.€July€1992€until€end€1992.€Actual€duration€was€1.€August€1992€until€end€1992.€ÌÌAt€the€end€of€the€Transfer€Phase€it€should€in€principal€have€been€possible€to€state€provisional€acceptanceÏof€the€simulator.€For€IPS€this€was€not€the€case.€After€this€date€numerous€updates€to€the€S/C€TM€and€TCÏdatabases€and€versions€of€the€on„board€ACC€application€software€together€with€related€documents€wereÏto€be€received.€The€OM€phase€of€the€simulator€was€extended€significantly€due€to€the€large€launch€slippageÏ(May€93€to€November€95).€This€enabled€many€outstanding€problems€to€be€resolved€before€finally€enteringÏthe€simulations€campaign€prior€to€launch.€All€together€more€than€500€Software€Problem€reports€in€3Ïcategories€of€priority€(critical,€urgent€and€routine)€have€been€handled€prior€to€launch.€Out€of€these€only€10Ïroutine€ones€were€still€not€solved€when€entering€the€simulations€campaign€which€took€place€in€3€phasesÏmainly€using€the€IHPS:ÌÌà œ à*à ˆ àà  à29€Mayà 9 à1995à  àà þ àtoà ê à22€Juneà h àà À à1995€€à  àSimulations€Program€at€ESOCÐ x)È$, Ðà œ à*à ˆ àà  à04€Julyà M àà 9 à1995à  àà þ àtoà ê à03€Augustà À à1995à  àSimulations€Program€at€VILSPAÐ N*ž%- Ðà œ à*à ˆ àà  à08€Augustà 9 à1995à  àà þ àtoà ê à15€Augustà À à1995à  àSimulations€Program€at€ESOCÐ $+t&. ÐÌà œ àÌÌÌÌÌÐ þ0N,5 Ѐ€€€€€€€€€€€€€€€€€€€€€€€€€à 9 àà % àà ¸ àà  àà þ àà ê àà Ö àà h àà À àà  àà p àà È àà  àà x àà Ð à€€€€€€7Ð ° Ðò òòòÔ‡Š±Š&&½Ôà œ àà ˆ àà  àà u àà a àà M àà 9 àà % àà ¸ àà  àà þ àà ê àà Ö àà h àà À àà  àà p àà È àà  àà x àà Ð àÌà œ àà ˆ àà  àà u àà a àà M àà 9 àà % àà ¸ àà  àà þ àà ê àà Ö àà h àà À àà  àà p àà È àà  àà x àà Ð àÌISO€Instrument€Simulators€IIIS€and€ISIS:ó óóóÔ#†&½&ŠŠ±o#ÔÐ ‚Ò ÐÌÌThe€ISO€Instrument€Simulators€were€developed€for€the€purpose€of€testing€the€Science€Operations€CentreÏInstrument€Stations€and€the€associated€instrument€operating€procedures.€Common€to€both€simulators€were€Ïan€upgrade€of€the€ISO€Platform€Simulator€implementing€fully€functional€models€of€the€ISO€instrumentÏpayloads€ISOPHOT,€LWS,€ISOCAM€and€SWS.€These€instrument€models€should€support€the€telecommandÏand€telemetry€interfaces€to€a€sufficient€level€of€detail€in€order€to€meet€these€objectives.€The€simulators€wasÏintended€for€use€at€ESOC€and€VILSPA€via€ODS€and€IDCS€and€also€located€at€ESTEC€with€directÏconnection€to€the€SOC.€ÌÌWork€started€with€a€2€man€month€study€performed€by€CRAY€Systems€on€the€subjects€of:ÌÌà œ à*€analysis€of€the€existing€draft€URD€provided€by€ESTEC;Ìà œ à*€evaluation€of€the€existing€document€and€their€relevance€for€instrument€modelling;Ìà œ à*€feasibility€of€developing€instrument€models;Ìà œ à*€IDCS€elements€to€be€included€for€the€ISIS;Ìà œ à*€Schedule€and€Costs.ÌÌThe€main€recommendation€was€that€the€on„board€software€executing€in€the€8086€processors€should€beÏemulated.€SWS€and€LWS€on„board€software€was€written€in€assembler€making€a€functional€rebuild€timeÏconsuming€and€cumbersome.ÌÌAnother€recommendation€of€the€study€was€to€combine€the€AD€and€DD€Phases€into€one€DID€Phase.€ThisÏwas€justified€by€the€critical€time€assigned€to€this€part€of€the€project€and€also€by€the€fact€that€most€of€theÏarchitectural€issues€had€been€resolved€in€the€IPS€development.Ì€€ÌFollowing€the€draft€Study€report€in€May€the€DID€started€in€June€1993€with€a€go€ahead€for€implementationÏof€the€ISOPHOT€and€the€IDCS€elements€to€be€included.€These€items€were€considered€sufficientlyÏdocumented€to€make€a€simulator€development€feasible.€The€remaining€LWS,€SWS€and€CAM€instrumentsÏcould€only€be€considered€feasible€to€model€if€a€solution€to€emulation€of€the€8086€processor€could€be€found.ÏA€further€assessment€on€the€8086€emulation€took€place€prior€to€the€final€study€report€in€July€1993€and€withÏpositive€results.€€For€this€purpose€the€source€code€of€the€Microtec€Inc.€XRAY86€development€environmentÏwas€acquired.€Subsequent€restructuring€and€adaptations€then€made€this€into€an€emulator€finally€enablingÏat€least€two€emulators€to€run€in€real€time€and€in€parallel€on€a€DEC€Alpha€Workstation.ÌÌThe€DID€Phase€was€terminated€by€end€of€May€with€a€delivery€including€all€instrument€models.€The€€Ïefforts€during€this€period€was€1420€mandays€against€the€original€estimated€of€1360.Ì€€ÌThe€following€transfer€Phase€concluded€in€November€1994€after€acceptance€tests€with€provisionalÏacceptance€granted€subject€to€completion€of€a€number€of€outstanding€urgent€Software€Problem€ReportsÏ(SPRs).ÌÌMaintenance€of€the€IPS/IHPS€and€IIIS/ISIS€was€carried€out€independently€until€launch.€Post€launch€sinceÏbegin€1996€one€contractor€at€VILSPA€is€fully€occupied€with€the€maintenance€of€all€simulator€versions.ÏUntil€date€248€Software€Problem€Reports€have€been€issued€in€three€priorities€out€of€which€22€of€lowestÏpriority€are€still€open.ÌÌÌà œ àÐ  0ð+4 Ї8ÌÌThe€IIIS€contributed€to€End„to„End€simulations€involving€SCC€and€SOC.€Primarily€these€tests€wereÏpreparations€for€the€System€Validation€Tests€(SVTs)€with€the€ISO€spacecraft€in€terms€of€dry€runs,€but€also€Ìpretests€for€these€dry€runs€were€found€necessary€to€iron€out€problems€both€in€the€simulator€and€controlÏsystems:ÌÌà œ à*à ˆ à14€Aprilà M àà 9 à1994€à  àtoà þ à25€Aprilà h à1994à À àEE0€à  àInterconnection€tests€ESOC(SCC)/ESTEC(SOC)Ð Š Ú Ðà œ à*à ˆ à11€Julyà M àà 9 à1994à  àto€à þ à18€Julyà h à1994à À àEE0à  àSame€tests€after€reinstallation€at€VILSPAÐ ` ° Ðà œ à*à ˆ àDecemberà 9 à1994à  àà þ àà ê àà Ö àà h àà À àEE1à  àPretesting€revolutions€260„265,€LVS/AOT€Ð 6 †  Ðà œ àà ˆ àà  àà u àà a àà M àà 9 àà % àà ¸ àà  àà þ àà ê àà Ö àà h àà À àà  àtestingÌà œ à*à ˆ à03€Januaryà 9 à1995à  àtoà þ à12€Januaryà h à1995à À àEE1à  àDry€run€in€preparation€for€SVT1€with€S/CÐ â 2  Ðà œ à*à ˆ à27€Marchà 9 à1995à  àtoà þ à03€Aprilà h à1995à À àEE2à  àPretesting€revolutions€227„233€AOT€Testing€Ð ¸  Ðà œ à*à ˆ à05€Aprilà M àà 9 à1995à  àtoà þ à12à ê àAprilà h à1995à À àEE2à  àDry€run€in€preparation€for€SVT2€with€S/CÐ ŽÞ  Ðà œ àÌÌÌReferences:ÌÌ1.€C.€Breneol€€€ð ðISO€Instrument€Simulator:€The€Role€of€the€Userðð.€Third€Workshop€on€Simulators€forÏEuropean€Space€Programmes.€ESA€wpp„084,€15„17€November€1994.Ì€Ì2.€R.€Smietana€and€K.€Booty.€ð ðThe€ISO€Operational€Training€Simulatorðð.€€Proceedings€of€the€2nd€ESA€Ïworkshop€on€Simulators€for€the€European€Space€Program.€25„27€November€1992.Ì€Ì3.€R.M.€Golding€and€C.J.€Todd.€ð ðThe€Infrared€Space€Observatory€Instrument€Simulator€(IIS)ðð.€ProceedingsÏof€the€Conference€on€Modelling€and€Simulations€1994€eds€Guash€and€Huber,€page€624.€Barcelona,€Spain.€ÏÐ  B’ ÐÌÓÙ:Ó