The study aims to appraise the merits of using Passive Radiators for Interplanetary Space Applications as it draws no power from the satellite system, and measuring its Effectiveness in Dissipating the heat developed inside the payload to space against Environmental Backloads incident over its surface from the Celestial Surroundings. It maintains the desired temperature range by Controlling Conductive and Radiative Heat Paths through the selection of Geometrical Configurations and Thermo-Optical Properties of the surface in addition to savings in Mass and Power respectively which has always been a crucial element in spacecraft design and configuration. A Parametric study is conducted to explore the scopes of using Passive Radiators. The entire system is Modelled and Simulated in FEA software UG NX 7.5 with a Flat Plate Radiator used in the initial Space Thermal Analysis. Correlations between Heat Transfer Capacity, Thermal Backloads, Radiator Area and the Operating Temperature are investigated to provide Design Guidelines for Consistent and Predictable Performance with minimum Degradation in a thermally stable orbit.

1. Thermal Analysis of Passive Radiator for
Inter-Planetary Space Applications
1

2. Overview
Literature Survey
Paper Presented
Objective
Introduction
ATCS & PTCS
Environmental Loads
Governing Equations
Modeling, Simulation and Boundary Conditions
Results
Conclusions
Annexure 2

3. Sr. Paper / Book Author / Editor Conclusions
1
Spacecraft Thermal Control
Handbook
Vol. 1: Fundamental
Technologies.
David G. Gilmore
Basics of Thermal control
systems, Space Radiators and
Environmental Loads and
Operating conditions of the
Satellite.
2
Design of Geosynchronous
Spacecraft
Brij N. Agrawal
Thermal control of Spacecraft,
Heat Transfer governing laws
and different types of Thermal
Control Strategies.
3
Thermal Control System of
the Moon Mineralogy
Mapper Instrument
Jose I. Rodriguez
(JPL)
Passive Thermal Cooling
Systems, Coatings, MLI
4
The Moon Mineralogy
Mapper (M3) on
Chandrayaan-1
Alok Chatterjee
(JPL)
Multi Layer Insulation (MLI)
Literature survey
3

4. Paper Presented
Presented Paper Titled:
“Thermal Analysis of Passive Radiators for
Inter-Planetary Space Applications”
In the International Conference:
“Engineering: Issues, Opportunities and
Challenges for Development”
On: Saturday, 9th April, 2016
ISBN: 978-81-929339-3-1
Jury:
Prof. Vratraj K. Joshi
Prof. Nikunj H. Patel
4

5. 5
Abstract
The current study aims to appraise the merits of using Passive Radiators for
Interplanetary Space Applications as it draws no power from the satellite
system, and measuring its Effectiveness in Dissipating the heat developed
inside the payload to space against Environmental Backloads incident over
its surface from the Celestial Surroundings.
It maintains the desired temperature range by Controlling Conductive and
Radiative Heat Paths through the selection of Geometrical Configurations
and Thermo-Optical Properties of the surface in addition to savings in Mass
and Power respectively which has always been a crucial element in spacecraft
design and configuration.
A Parametric study is conducted to explore the scopes of using Passive
Radiators. The entire system is Modelled and Simulated in FEA software UG
NX 7.5 with a Flat Plate Radiator used in the initial Space Thermal
Analysis. Correlations between Heat Transfer Capacity, Thermal Backloads,
Radiator Area and the Operating Temperature are investigated to provide
Design Guidelines for Consistent and Predictable Performance with
minimum Degradation in a thermally stable orbit.

6. objective
Conduct Parametric analysis to understand the
effects of change in the values of parameters like
Radiator Area and Thickness over the heat
transfer rate from a Satellite.
We aim at providing suitable design guidelines
for maximizing the dissipation of heat generated
inside the satellite to space by using passive
radiators.
6

7. Introduction
Thermal Control
System
Active Thermal
Control System
Passive Thermal
Control System
Allowable Temperature Limits
Heat Produced by Electronic Systems
Heat MUST be dissipated to space
HOW??
7

8. Active THERMAL CONTROL SYSTEM
(ATCS)
Used where Narrow Temperature range are to be
maintained
Uses electric power input
Heaters, coolers, coolant storage system used
Moving Parts and fluids involved
Heavy and costly cooling system
8

9. PASSIVE THERMAL CONTROL SYSTEM
(PTCS)
NO Moving Parts
NO Moving Fluids
NO Electric Power Input
Geometrical Configurations
Thermo-Optical Properties of Surface
Thermal Insulations 9

10. 10
Environmental Loads
Solar Flux
Direct sunlight is the dominating source of
heating on the satellite surface.
Albedo
It is the sunlight reflected off a planet’s surface.
Planet Shine
Infrared energy emitted by a planet by the
virtue of its own temperature.

11. 11
SOLAR FLUX
PLANET SHINE
ALBEDO

12. 12
Governing Equations
Steady - state
Heat Balance Equation:
[Heat Radiated] =
[Heat Absorbed]+[Instrumental Heat Dissipation]
[2]

13. 13
Governing Equations
Transient state
Based on Lumped Parameter Analytical
Method, Heat Balance equation for each node:
[2]
Neglecting Albedo and Earth Radiation
[2]

14. 14
Case Study: Flat Plate Radiator
Modeling of Radiator
Dissipator
Flat Plate Radiator
Thermal Strap
Package body
With MLI

15. Modeling & Meshing
Package with MLI

16. 16
Boundary conditions applied
Bottom face of Package = 20o C
Thermal Coupling between Dissipator and base
of package: R= 60 C/W
Thermal Coupling between Dissipator and
Thermal Strap: h= 300 W/m2 C
Thermal Coupling between Thermal Strap and
Radiator: h= 300 W/m2 C
Coupling between MLI and Package: h=0.03
W/m2 C
[4]

17. 17
300×150×2; Q=3.75 W
Sr. No. Part Min. Temp Max. Temp
1 Radiator 596.70 602.43
2 Dissipator 514.15 544.05
3 Thermal Strap 547.22 581.22
4 Package 20.00 59.00
results

18. 18
results
Sr. Dimension Part
Steady State Condition Transient Conditions
Dissipation
Min. Temp Max. Temp Min. Temp Max. Temp
1 300*150*2
Radiator 596.70 602.43 20.00 208.02
3.75
Dissipator 514.15 544.05 20.00 189.18
Thermal Strap 547.22 581.22 20.00 197.53
Package 20.00 59.00 20.00 72.17
2 300*150*2
Radiator 1299.19 1304.88 20.00 412.61
15
Dissipator 1182.87 1254.07 20.00 442.06
Thermal Strap 1255.83 1283.72 20.00 420.57
Package 21.52 59.00 20.00 72.17
3 300*150*3
Radiator 596.85 600.64 20.00 218.95
3.75
Dissipator 514.15 544.05 20.00 204.79
Thermal Strap 547.22 581.22 20.00 213.78
Package 20.00 59.00 20.00 72.17
4 300*150*3
Radiator 1299.33 1303.12 20.00 401.73
15
Dissipator 1182.86 1254.06 20.00 441.77
Thermal Strap 1248.06 1283.70 20.00 419.45
Package 20.00 59.00 20.00 72.17

19. 19
results
Sr. Dimension Part
Steady State Condition Transient Conditions
Dissipation
Min. Temp Max. Temp Min. Temp Max. Temp
5 350*200*2
Radiator 725.24 733.14 20.00 240.82
3.75
Dissipator 612.27 653.20 20.00 221.75
Package 20.00 58.30 20.00 71.60
Thermal Strap 667.76 704.12 20.00 233.65
6 350*200*3
Radiator 725.44 730.664 20.00 229.62
3.75
Dissipator 612.26 653.19 20.00 215.28
Package 20.00 58.30 20.00 71.60
Thermal Strap 657.76 704.11 20.00 224.12
7 350*200*3
Radiator 1426.30 1431.52 20.00 403.00
15
Dissipator 1281.50 1360.46 20.00 448.73
Package 20.00 58.30 20.00 71.60
Thermal Strap 1357.05 1404.97 20.00 426.49
8 500*300*2
Radiator 1394.21 1420.11 20.00 417.74
3.75
Dissipator 1192.14 1295.43 20.00 372.99
Package 20.00 57.46 20.00 70.85
Thermal Strap 1306.80 1339.83 20.00 389.14

20. 20
results
Sr. Dimension Part
Steady State Condition Transient Conditions
Dissipation
Min. Temp Max. Temp Min. Temp Max. Temp
9 500*300*2
Radiator 2092.17 2109.45 20.00 515.14
15
Dissipator 1861.90 1988.10 20.00 520.01
Package 20 57.46 20.00 70.85
Thermal Strap 2003.82 2037.24 20.00 505.82
10 500*300*3
Radiator 1394.75 1412.03 20.00 374.09
3.75
Dissipator 1192.14 1285.43 20.00 339.37
Package 20.00 57.46 20.00 70.85
Thermal Strap 1306.80 1339.82 20.00 353.07
11 500*300*3
Radiator 2092.17 2109.45 20.00 515.14
15
Dissipator 1861.90 1988.10 20.00 520.01
Package 20 57.46 20.00 70.85
Thermal Strap 2003.82 2037.24 20.00 505.82

21. 21
Conclusions
1. Increasing the surface area of the radiator does not increase
the heat transfer from the satellite.
2. Increased Surface Area  Increased Incident Load 
Reduced Heat Transfer.
3. Increasing the thickness of the radiator does not increase the
heat transfer from the satellite as its surface temperature
increases significantly.

22. 22
Validation of Results and Conclusions
Spacecraft Thermal Vacuum Test
[2]
Infrared Simulation
[2]

23. 23
references
1. Spacecraft Thermal Control Handbook, Vol.1; Fundamental Technologies,
Chapter 1-6, David G. Gilmore, Pages 1-222.
2. Design of Geosynchronous Spacecraft, Chapter 5 – Thermal Control, Brij N.
Agrawal.
3. Thermal Control System of the Moon Mineralogy Mapper Instrument, Josh I
Rodriguez, Jet Propulsion Laboratory, California Institute of Technology.
4. “The Moon Mineralogy Mapper (M3) on Chandrayaan-1” by Alok Chatterjee,
Padma Varanasi.
5. “The Moon Mineralogy Mapper (M3) for lunar science” by A. Chatterjee,
Padma Varanasi, A.S.K Kumar.
6. “Thermal Control System of the Moon Mineralogy Mapper Instrument” by
Jose I. Rodriguez, Jet Propulsion Laboratory, California Institute of
Technology.

24. 24
Radiator size calculator
(Java netbeans 8.0.1)

25. 25
Code for radiator

26. 26
Business model canvas

27. 27
Thank You.

28. 28

29. 29
Supporting data

30. 30

31. 31