Micromaps host Satellite Design Proposal

List of Figures iv

List of Tables v

List of Abbreviations vi

List of Symbols vii

Chapter 1: Introduction and Problem Definition 9

1.1 Descriptive scenario 9

1.2 Scope 10

1.3 Needs, alterables, and constraints 10

1.4 Value system design 11

1.5 Summary and conclusions 13

Chapter 2: Satellite Configuration and Components 14

2.1 Configuration 14

2.2 Structure 16

2.2.1 Requirements 16

2.2.2 Launch vehicle selection 17

2.2.3 Bus structure 17

2.2.4 Structure configuration 20

2.2.5 Component layout 21

2.3 ADCS 22

2.3.1 Attitude control architecture 22

2.3.2 Attitude control modes 22

2.3.3 Disturbance torques 23

2.3.4 Hardware 26

2.4 Power 32

2.4.1 Power Requirements 32

2.4.2 Power Generation 33

2.4.3 Energy Storage 35

2.5 Thermal 37

2.6 Communication 42

2.6.1 Uplink 43

2.6.2 Downlink 44

2.6.3 AMSAT 44

2.7 Command and data handling 45

2.8 Summary 45

Chapter 3: Mission Operations 45

3.1 Orbits 45

3.1.1 Coverage 46

3.1.2 Orbit prediction 47

3.1.3 Orbit simulation 47

3.1.4 Orbit characteristics 47

3.1.5 Lifetime 48

3.2 Summary 51

Chapter 4: Cost Analysis 52

Chapter 5: Summary, Conclusions, and Remaining Work 54

References 55

Appendix A: MATLAB Power Code 57

Appendix B: HokieSat Loop Antenna 59

Appendix C: MATLAB Earth Ground Coverage Code 60

Appendix D: MATLAB Disturbance Torque and Attitude Actuator Sizing Code 63

Figure 1: Objective hierarchy chart 12

Figure 2: Internal configuration of HokieSat7 14

Figure 3: External configuration of HokieSat7 15

Figure 4: VASCAT external configuration 16

Figure 5: Illustration of isogrid construction15 20

Figure 6: Ithaco CES sensor head diagram11 26

Figure 7: An isometric diagram of the BEI Systron Donner QRS-11 rate gyro17 27

Figure 8: A three view drawing of the Ithaco IM-103 magnetometer11 28

Figure 9: A cut-away diagram showing the interior of an Ithaco Type A momentum wheel11 30

Figure 10: External configuration diagram of an Ithaco TR30CFR magnetic torque bar11 31

Figure 11: VASCAT power model 35

Figure 12: Cycle life versus DOD17 36

Figure 13: Uplink transceiver5 43

Figure 14: Downlink transmitter5 44

Figure 15: Lifetime as a function of altitude 48

Figure 16: Lifetime as a function of drag coefficient for a 400 km altitude orbit 49

Figure 17: Lifetime as a function of drag coefficient for a 500 km altitude orbit 49

Figure 18: Lifetime as a function of drag area for a 400 km altitude orbit 50

Figure 19: Lifetime as a function of drag area for a 500 km altitude orbit 50

Figure 20: Lifetime as a function of orbit inclination 51

Figure 21: Loop antenna assembly from HokieSat drawing package 59

Figure 22: Copper tube loop from HokieSat drawing package 59

Table 1: List of needs, alterables, and constraints for host satellite design 11

Table 2: List of objectives and their associated subsystems 12

Table 3: Mass budget by subsystem 17

Table 4: Structural requirements16 18

Table 5: Limiting loads on structure during launch 19

Table 6: Trade study of component mounting techniques 22

Table 7: MicroMAPS imposed attitude requirements19 23

Table 8: Estimated structural properties of the VASCAT 25

Table 9: Estimated orbital properties of the VASCAT 26

Table 10: Estimated disturbance torques 26

Table 11: Properties of the Ithaco CES11 27

Table 12: Properties of the Valley Forge Composite Technologies Sun Sensor18 28

Table 13: Properties of the BEI Systron Donner QRS-11 rate gyro17 29

Table 14: Properties of the Ithaco IM-103 magnetometer11 29

Table 15: VASCAT orbital and environmental properties 30

Table 16: Properties of the Ithaco TW-4A12 momentum wheel11 31

Table 17: Properties of the Ithaco TR30CFR magnetic torque bar11 32

Table 18: Component power requirements 33

Table 19: Daylight and eclipse power budget 34

Table 20: Design parameters for preliminary VASCAT thermal analysis 38

Table 21: VASCAT Temperature Limits (°C) 39

Table 22: Component internal power dissipations 40

Table 23: Environmental fluxes in space (W/m2) 41

Table 24: Surface properties 41

Table 25: Temperatures of the VASCAT components 42

Table 26: Uplink receiver specifications5 44

Table 27: Downlink transmitter specifications5 45

Table 28: The VASCAT cost estimate using PECM20 54