2. October 2005 Ahmedabad 3rd Indo-French Workshop on MEGHA-TROPIQUES 2 SATELLITE ALTITUDE AND REPEAT CYCLE Michel Capderou (LMD / IPSL Paris)

3. October 2005 Ahmedabad 3rd Indo-French Workshop on MEGHA-TROPIQUES 3  The recurrence (or repeatitivity) with a defined repeat cycle, is a well known feature for Sun-synchronous satellites.

4. October 2005 Ahmedabad 3rd Indo-French Workshop on MEGHA-TROPIQUES 4

5. October 2005 Ahmedabad 3rd Indo-French Workshop on MEGHA-TROPIQUES 5  For weak-inclination satellites, this property is rarely used. In the case of Megha-Tropiques ( i = 20°), the recurrence is not required. But we have to avoid the 1-day recurrence (every day, the satellite overpasses the same track).

6. October 2005 Ahmedabad 3rd Indo-French Workshop on MEGHA-TROPIQUES 6

7. October 2005 Ahmedabad 3rd Indo-French Workshop on MEGHA-TROPIQUES 7 MT 866

8. October 2005 Ahmedabad 3rd Indo-French Workshop on MEGHA-TROPIQUES 8  1-day recurrence : 14 rev. in 1 day  h 1 = 814 km With a 7-day repeat cycle, we are sure to evade this bad spatial sampling. 7-day recurrence : 97 rev. in 7 days  h 2 = 866 km 1-day recurrence : 98 rev. in 7 days  h 1 = h 2 - 52 km

9. October 2005 Ahmedabad 3rd Indo-French Workshop on MEGHA-TROPIQUES 9

10. October 2005 Ahmedabad 3rd Indo-French Workshop on MEGHA-TROPIQUES 10 MEGHA-TROPIQUES: A VERY PARTICULAR SAMPLING Michel Capderou (LMD / IPSL Paris)

11. October 2005 Ahmedabad 3rd Indo-French Workshop on MEGHA-TROPIQUES 11  Views of the MT orbit (Terrestrial referential frame)  Views of the ground track

12. October 2005 Ahmedabad 3rd Indo-French Workshop on MEGHA-TROPIQUES 12

13. October 2005 Ahmedabad 3rd Indo-French Workshop on MEGHA-TROPIQUES 13

14. October 2005 Ahmedabad 3rd Indo-French Workshop on MEGHA-TROPIQUES 14

15. October 2005 Ahmedabad 3rd Indo-French Workshop on MEGHA-TROPIQUES 15

16. October 2005 Ahmedabad 3rd Indo-French Workshop on MEGHA-TROPIQUES 16

17. October 2005 Ahmedabad 3rd Indo-French Workshop on MEGHA-TROPIQUES 17  Ground track with LST (notation of the Local Solar Mean Time)

18. October 2005 Ahmedabad 3rd Indo-French Workshop on MEGHA-TROPIQUES 18

19. October 2005 Ahmedabad 3rd Indo-French Workshop on MEGHA-TROPIQUES 19

20. October 2005 Ahmedabad 3rd Indo-French Workshop on MEGHA-TROPIQUES 20

21. October 2005 Ahmedabad 3rd Indo-French Workshop on MEGHA-TROPIQUES 21

22. October 2005 Ahmedabad 3rd Indo-French Workshop on MEGHA-TROPIQUES 22

23. October 2005 Ahmedabad 3rd Indo-French Workshop on MEGHA-TROPIQUES 23  Precession cycle : the time interval needed for the hour angle of ascending node to vary by 24 hr.  For Megha-Tropiques, the precession cycle is short : 51 days

24. October 2005 Ahmedabad 3rd Indo-French Workshop on MEGHA-TROPIQUES 24 12 hr  26 day Precession cycle J=1 J=27

25. October 2005 Ahmedabad 3rd Indo-French Workshop on MEGHA-TROPIQUES 25  Other particular point, resulting of the 20-degree inclination: for the latitudes between 10° and 25° (North and South), the temporal sampling is represented by - a « pack » of overpasses - followed by a « lack » (without overpass).

26. October 2005 Ahmedabad 3rd Indo-French Workshop on MEGHA-TROPIQUES 26

27. October 2005 Ahmedabad 3rd Indo-French Workshop on MEGHA-TROPIQUES 27

28. October 2005 Ahmedabad 3rd Indo-French Workshop on MEGHA-TROPIQUES 28

29. October 2005 Ahmedabad 3rd Indo-French Workshop on MEGHA-TROPIQUES 29

30. October 2005 Ahmedabad 3rd Indo-French Workshop on MEGHA-TROPIQUES 30

31. October 2005 Ahmedabad 3rd Indo-French Workshop on MEGHA-TROPIQUES 31

32. October 2005 Ahmedabad 3rd Indo-French Workshop on MEGHA-TROPIQUES 32

33. October 2005 Ahmedabad 3rd Indo-French Workshop on MEGHA-TROPIQUES 33

34. October 2005 Ahmedabad 3rd Indo-French Workshop on MEGHA-TROPIQUES 34

35. October 2005 Ahmedabad 3rd Indo-French Workshop on MEGHA-TROPIQUES 35  Scanning ground track for ScaRaB instrument  Across track swath  Scanning ground track for MADRAS instrument  Conical swath

36. October 2005 Ahmedabad 3rd Indo-French Workshop on MEGHA-TROPIQUES 36

37. October 2005 Ahmedabad 3rd Indo-French Workshop on MEGHA-TROPIQUES 37

38. October 2005 Ahmedabad 3rd Indo-French Workshop on MEGHA-TROPIQUES 38  Sky plot  Visibility diagram (elevation h>4°) for Bangalore  Visibility diagram (elevation h>4°) for 4°-station and Equatorial station

39. October 2005 Ahmedabad 3rd Indo-French Workshop on MEGHA-TROPIQUES 39

40. October 2005 Ahmedabad 3rd Indo-French Workshop on MEGHA-TROPIQUES 40

41. October 2005 Ahmedabad 3rd Indo-French Workshop on MEGHA-TROPIQUES 41

42. October 2005 Ahmedabad 3rd Indo-French Workshop on MEGHA-TROPIQUES 42

43. October 2005 Ahmedabad 3rd Indo-French Workshop on MEGHA-TROPIQUES 43

44. October 2005 Ahmedabad 3rd Indo-French Workshop on MEGHA-TROPIQUES 44  View from the sky  If you are aboard Megha-Tropiques

45. October 2005 Ahmedabad 3rd Indo-French Workshop on MEGHA-TROPIQUES 45

46. October 2005 Ahmedabad 3rd Indo-French Workshop on MEGHA-TROPIQUES 46

47. October 2005 Ahmedabad 3rd Indo-French Workshop on MEGHA-TROPIQUES 47  Maps  Graphs  Diagrams from IXION software © MC / LMD