Thermal analysis for CINEMA JaeGun Yoo (jaegunsd@khu.ac.kr) School of Space Research

1. Thermal analysis for CINEMA • JaeGunYoo • (jaegunsd@khu.ac.kr) • School of Space Research • Kyung Hee University

2. Contents 1. Process of thermal analysis 2. Used properties to analyze - material properties - thermo-optical properties 3. Conditions - thermal coupling condition(principle of flowing conduction) - orbit condition 4. Simulation results of thermal analysis(till now) 5. Summary 6. Future plan

3. 1. Process of thermal analysis Objective of Thermal Analysis To maintain all subsystems and components of a spacecraft within their operating temperature limits for all mission phases Typical Operating Temperature Ranges Subsystems Electronics Structure Batteries Solar Cell Magnetometer Operating Temperature Range (C) 0 to +40 -45 to +65 +5 to +20 -100 to +100 +0 to +70

4. Emitted Mean value of Radiation Direct Solar Flux 1358 5 W / m 2 G S s Albedo (30 5)% Earth Infrared of Direct Solar, a 237 21 W / m 2 q l 1. Process of thermal analysis Thermal Environment of Spacecraft System • Thermal state of the satellite results from - Thermal energy received from Sun and Earth - Thermal energy generated from either waste heat or from heaters Low-Earth Orbit Spacecraft Earth

5. 1. Process of thermal analysis NX 6.0 TMG Program

6. 1. Process of thermal analysis Simplify modeling Meshing Modeling CINEMA.prt CINEMA_fem_i.prt CINEMA.fem • Material properties • Physical properties • Thermo-Optical properties • Element size Model Correction 1st Solving Run & Case Simulation CINEMA.sim Finalize Thermal Design & Prediction Determine Thermal Design & Prediction • Thermal Coupling • Heat Dissipation • Radiation • Conductivity • Attitude • Orbit Thermal Balance Test Model Correction

7. 1. Process of thermal analysis The present time 4 weeks ago

8. 1. Process of thermal analysis Patch ANT copper Patch ANT rogers Standoff Standoff Solar cell Solar cell PCB

9. 2. Used properties to analyze - Material properties of components (Reference to www.matweb.com)

10. 2. Used properties to analyze - Thermo-optical properties of components

11. 3. Conditions Finite Elements Method - Nodes To develop a thermal network and apply numerical techniques to its solution, one subdivides the thermal system into finite subvolumes called nodes. The thermal properties of each node are considered to be concentrated at the central nodal point of each subvolume.

12. 3. Conditions

13. 3. Conditions In the case of parallel paths G = conductance k = conductivity A = cross-sectional area L = distance between adjoining nodes Two or more parallel conduction paths between nodes may be summed to create one conductor value by the following equation.

14. 3. Conditions

15. 3. Conditions In the case of series paths G = conductance k = conductivity A = cross-sectional area L = distance between adjoining nodes This equation may be helpful in computing the conductors between two dissimilarly shaped nodes or two nodes of dissimilar materials, as shown left formula.

16. 3. Conditions Total conductance between Solar PCB and Chassis

17. 3. Conditions Total conductance between Solar PCB and Chassis

18. 3. Conditions Total conductance between Solar PCB and Chassis

19. 3. Conditions Heat transfer coefficient between Patch antenna and Chassis

20. 3. Conditions Heat transfer coefficient between Patch antenna and Chassis

21. 3. Conditions Heat transfer coefficient between Patch antenna and Chassis

22. 3. Conditions • Give 3-Watt to bottom side of CINEMA 3W

23. 3. Conditions - Orbit condition

24. 3. Conditions -One orbit Period : 5798 sec -End Time : 30,000 sec(5 obits) , Time Interval : 300sec -Local Time at Ascending Node : 10:30:00

25. 4. Simulation results of thermal analysis

26. 4. Simulation results of thermal analysis The min, max temperature(5 orbits)

27. 4. Simulation results of thermal analysis The min, max temperature(5 orbits)

28. 4. Simulation results of thermal analysis The temperature at ascending node(dayside)

29. 4. Simulation results of thermal analysis The temperature at center of eclipse(nightside)

30. 4. Simulation results of thermal analysis The temperature on the chassis(5 orbits)

31. 4. Simulation results of thermal analysis The temperature on the chassis(5 orbits) x 300sec

32. 4. Simulation results of thermal analysis The temperature on the side solar panel(5 orbits)

33. 4. Simulation results of thermal analysis The temperature on the side solar panel(5 orbits) x 300sec

34. 4. Simulation results of thermal analysis The temperature on the top solar panel(5 orbits)

35. 4. Simulation results of thermal analysis The temperature on the top solar panel(5 orbits) x 300sec

36. 4. Simulation results of thermal analysis The Flux of the earth IR(w/mm2)

37. 4. Simulation results of thermal analysis The Flux of the earth ALBEDO(w/mm2)

38. 4. Simulation results of thermal analysis The Flux of the Sun(w/mm2)

39. 5. Summary

40. 6. Future plan • I will make a new thermal model with below these steps • to get more accuracy temperature. ☞ analyze external components in more detail. - consider heat dissipation of solar panels - change materials of the patch ANT(copper part, RT duroid part) ☞ include all internal components for thermal analysis. - avionics - STIEN - magnetometer ☞ perform thermal analysis according to operation modes - housekeeping mode - safe mode - science mode

41. Thank you