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아리랑 위성 1 호 (KOMPSAT-1) 궤도 변화와 우주환경 변화 비교

아리랑 위성 1 호 (KOMPSAT-1) 궤도 변화와 우주환경 변화 비교. 박진영 1,2 , 문용재 2 , 조경석 2 , 김해동 3 , 김관혁 2 , 김연한 2 , 박영득 2 , 이유 1 1 충남대학교 , 2 한국천문연구원 , 3 한국항공우주연구원 한국우주과학회 춘계 학술대회 2005. 4. 29. Contents. 1. Introduction 2. Selection of event by using Solar and Geomagnetic data

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아리랑 위성 1 호 (KOMPSAT-1) 궤도 변화와 우주환경 변화 비교

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  1. 아리랑 위성 1호(KOMPSAT-1)궤도 변화와 우주환경 변화 비교 박진영1,2, 문용재2, 조경석2, 김해동3, 김관혁2, 김연한2, 박영득2, 이유1 1충남대학교, 2한국천문연구원, 3한국항공우주연구원 한국우주과학회 춘계 학술대회 2005. 4. 29

  2. Contents 1. Introduction 2. Selection of event by using Solar and Geomagnetic data 3. Analysis of KOMPSAT-1 Drag force data 4. Summary 5. Further work

  3. Motivation 11/20 -472nT 10/30 -388nT 11/20 -472nT • Orbit Prediction Error : about 16km (조경석 등 2004)

  4. Space Environment Variations Sun Coronal Mass Ejections Soft X-ray fluxes Energetic Charged Particles Coronal Holes EUV fluxes (10.7 cm flux) Geomagnetic Field Neutral Atmosphere Density Radiation Environment Ionosphere Effects on Satelites

  5. Space Environment Variations Sun Coronal Mass Ejections 2~3 day ~ 8 min Soft X-ray fluxes Energetic Charged Particles Coronal Holes F10.7 EUV fluxes (10.7 cm flux) Dst Geomagnetic Field Neutral Atmosphere Density Radiation Environment Ionosphere Effects on Satelites

  6. Drag acceleration equation drag coefficient total density direction unit vector aD= ½CD A/M r Vr2 u (Knowles,2001) area/mass ratio relative velocity < KOMPSAT-1 data > aD, C D = program A = 5.871m2 M = 448kg Vr = 7.5 m/sec2 Density r

  7. Scale factors and empirical accelerations 1. Computed orbit, integrated from initial state based only on force models

  8. Scale factors and empirical accelerations 2. Tracking observations (SLR, GPS) do not match the computed orbit

  9. Scale factors and empirical accelerations 3. The modeled aerodynamic force is multiplied with a scale factor, estimated from the data, so that the computed orbit better matches the observations

  10. 2. The selection of Solar and Geomagnetic Data 1)Geoeffective CME 2)Non-geoeffective CME Weak Flare Strong Flare W E E W Sun Sun Sun : X-ray < M-class Earth (Dst) : <-100nT Sun : X-ray > X-class and East limb

  11. 3.Analysis of KOMPSAT-1 Drag1) 2001.03.28 (CME, Dst = -387nT) : -Dst index : Drag : F10.7 index : Drag F10.7 vs Drag Dst vs Drag

  12. 2) 2002.07.20 ( Strong Flare ) : -Dst index : Drag : F10.7 index : Drag Dst vs Drag F10.7 vs Drag

  13. 4) F10.7 vs Drag at 2002.07.20

  14. 3) Dst vs Drag in total data r = 0.6 (0.8)

  15. 5) MSISE-90 density vs Satellite Drag • Blue line : MSISE-90 model • Black line : Satellite Drag 2002.07.20 2001.03.28

  16. 6) Estimated & Model density MSISE-90 density Real density MSISE-90 density Real density • What can be the reason? - Current atmospheric models are statistical and do not allow a short term prediction for a give altitude. (Space Weather Effects Catalogue, ESWS, 2001) 2002.07.20 2001.03.28

  17. 4. Summary • Satellite Drag and Dst have similar patterns. • Satellite Drag started with the solar flare at the same time and then has a peak 1 day later. (the best cross correlation at 1-day time delay prediction of satellite drag ) • MSISE-90 model density and Drag also have similar patterns. • MSISE-90 do not allow a short term (such as storms) prediction

  18. 5. Further work 1. Investigate more events in long term 2. Examine other factors associated with Satellite Drag ex) Proton flux, AE index, etc 3. Compare the Drag with empirical high atmosphere models such as NRLMSISE-00.

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