BillikenSat – IINano-Satellite that conforms to the CubeSat standard

Team Leader: Darren PaisADCS: Sonia HernandezStructures: Paul LemonThermal: Nathaniel Clark

MISSION: The BillikenSat-II team will develop a working prototype Pico-satellite that conforms to the CubeSat standard, and one that incorporates Bio-Fuel cell test experiment as our payload. We will, by the end of this year, build a flight ready version of BillikenSat-II, after rigorous testing and verification of our design.

Agenda for today

Introduction Payload Structures Thermal ADCS Conclusions

• Overview of mission experiment

• Detailed description and progress in key areas:

Payload Structures Thermal Attitude Determination Attitude Control Electrical and Computer Engineering, Interfaces

Emphasize the integrated, multi-disciplinary nature of BillikenSat – II.

Payload Concept

Introduction Payload Structures Thermal ADCS Conclusions

Payload Fuel Cell

Introduction Payload Structures Thermal ADCS Conclusions

Material: Gold Plated Aluminum

Membrane: NAFION ®

Fuel: Ethanol, Glycerol, sugar,etcIn our satellite: Flat Beer

Payload Structure

Introduction Payload Structures Thermal ADCS Conclusions

Material• Poly Ether Ether Ketones- PEEK• Conducts 1/1000th the amount of heat relative to Aluminum • Upper working temperature of 250 oC

Tank Design• Plate and tank bolted together around seal• PEEK pipe for pressurization on ground and testing• Tank able to withstand 1500 psi

Screw

Pipe

Ferrule

Ref: Gere, Mechanics of Materials, Thomson 2003

Structural Assembly

Introduction Payload Structures Thermal ADCS Conclusions

• Internal components bolted to mounts• Bolts and mounts universal • Spring washers and lock-nuts ensure connection

• Exterior panels screw or slide into rails• Panels provide extra strength to structure• PCB and carbon composite panels under consideration

Composite panel

Solar Cell

Structures- Putting things together

Introduction Payload Structures Thermal ADCS Conclusions

(1) Main Structural Bus (2) Exploded View (3) Assembled Satellite

Ref: Megson, Aircraft Structures for Engineers, Butterworth 1999

Structures- 3 view and dimensions

Introduction Payload Structures Thermal ADCS Conclusions

Electronic Boards

Battery Box

Payload

Support Panel

Introduction Payload Structures Thermal ADCS Conclusions

Preliminary design • Cross braces resist tension effectively• Slots for exterior panels to slide into

Evolved design • Thicker cross bars to better resist compression and bending• More access to interior for mounting, etc.• Easier to manufacture• 4 side panels screwed on, 2 slide into place• Mount deflection due to 9g loading is negligible (1.48x10-4mm)

Old Design

Evolved Design

Vibration Modeling

Introduction Payload Structures Thermal ADCS Conclusions

• High Level Qualification studied• Frequency range expected on launch 0-2000 Hz • Pro Mechanica Modal analysis conducted• Calculations performed to confirm computer results• Natural frequencies studied to ensure no match with rocket frequencies

Crossbeam Mode 1

Pro Mechanica = 3051 Hz

Theory Calculation = 3039 HzRef: Mechanical Vibrations, S. Rao (1998)

Modal response of constrained side panel in Mode 1.

Note: Modal deflection highly exaggerated in clip

Battery Box Design

Introduction Payload Structures Thermal ADCS Conclusions

Design• House batteries while providing access• Provide Structural backbone• Resist loads from many directions

Analysis• Natural frequencies found using Pro-Mechanica Mode 1 = 1459 Hz Mode 2 = 2702 Hz• Maximum deflection under 9g load due to batteries = 0.0028 mm

Mass Budget

Introduction Payload Structures Thermal ADCS Conclusions

• Total mass estimated to be 825 gram• 175 grams available for contingency

Structure44%

Electrical37%

Thermal2%

ADCS5%

Payload12%Sub System Mass (g)

Structure 362ADCS 40

Electrical 306Payload 102Thermal 15TOTAL 825

System Interface Diagram

Introduction Payload Structures Thermal ADCS Conclusions

Introduction Payload Structures Thermal ADCS Conclusions

Orbital Parameters

BillikenSat will follow Sun synchronous / near polar orbit

Orbital Parameters DNEPR 07

Type of Orbit Sun synchronous

Inclination 98 deg

Eccentricity 0.009

RAAN 256 deg

Argument of Perigee 0 deg

Mean Anomaly 0 deg

LTAN 22:30 UTCG

Altitude Perigee 660 km

Altitude Apogee 772 km

Period 90 min

Introduction Payload Structures Thermal ADCS Conclusions

Orbital Simulation

Satellite is in sunlight twice as much as in eclipse

Introduction Payload Structures Thermal ADCS Conclusions

Communication Window

21 deg.

Type of antenna:

• Model 436CP42 U/G

• Beam-width 21° circular

• 4 communication windows per day • 4-7 minutes per communication window

Introduction Payload Structures Thermal ADCS Conclusions

Equilibrium Temperatures

Radiation absorbed:

Radiation emitted:

Temperature equilibrium:

ia AGQ

4bodyre TAQ

4bodyri TAAG

:

:

:

:

:

:

r

i

A

A

G

irradiation

absorptivity

incident area

emissivity

Stefan-Boltzmann const.

radiating area

CT o4.46max CT o7.111min ,

aQ

eQ

Introduction Payload Structures Thermal ADCS Conclusions

Actual Temperatures1. Find total energy transfer rate for

sunlight

2. Use energy transfer rate to find temperature at end of sunlight

3. Find total energy transfer rate for eclipse

4. Use energy transfer rate to find temperature at end of eclipse

• Repeat

Operating Range: -40.9oC to 44.2oC

Ref: Cengel, Intro to Thermodynamics and Heat Transfer, McGraw Hill 1997

Introduction Payload Structures Thermal ADCS Conclusions

Heat Transfer of Payload Box

4bodyre TAQ

Heat loss at 25oC of 2.57 W

Heater power is 1.13 W

Surface treatment: aluminized Mylar© ‘space blanket’ with emissivity of 0.03

Payload survival range 4oC to 40oC

Introduction Payload Structures Thermal ADCS Conclusions

Multi Layer Insulation (MLI)

1

10

nQQ , n = number of layers

Q

0Q

Ref: Incropra, Fundamentals of Heat and Mass Transfer, Wiley 2001

Introduction Payload Structures Thermal ADCS Conclusions

MLI ComponentsMylar©: 0.025 mm

Dacron web: 0.18 mm

Dacron

Mylar

Single Layer Pair for MLI

Introduction Payload Structures Thermal ADCS Conclusions

Active Thermal Control

Thermofoil© Heater

43.94 mm (1.73 in) diameter 0.3 mm (0.012 in) thickness

Platinum RTD

1.24 x 1.7 x 2.41 mm

(0.049 in x 0.067 in x0.095 in)

Introduction Payload Structures Thermal ADCS Conclusions

Feedback Loop

platinum RTD

If V>V @ 15oC

If V<V @ 30oC

take no action

turn on heater

turn off heater

true

false

false

true

Heating for 7 min 16 sec, cooling for 18 min 18 sec

Introduction Payload Structures Thermal ADCS Conclusions

Electronics• Most components can operate within

temperature range– Battery pack: how much insulation?

• Calculate heat transfer through payload wiring

• Testing– Find actual performance of heater– Calibrate resistance temperature

detector (RTD)

Introduction Payload Structures Thermal ADCS Conclusions

1. If gyro is not spinning: wheel flops over

2. If gyro is spinning: Gyro rotates in a direction perpendicular to the applied force

•Based on principle of conservation of angular momentum.

•Once spinning, it tends to resist changes to its orientation due to the angular momentum of wheel.

Gyroscopes will determine at what rate the satellite is turning

Attitude Determination: Gyroscopes

Introduction Payload Structures Thermal ADCS Conclusions

Tradeoff study of gyroscopesSensor Fibersense

FOG 1Analog

ADXRS150Analog

ADXRS300SiliconSensingCRS 03

HoneywellCMG

Pro reason Fiber optics:very highresolution

Small size:mass &volume

Small size:mass &volume

Extremelyhigh

accuracy

Extremelyhigh

accuracy

Pro reason Power req.+/- 5V DC

Power req.+/- 5V DC

Power req.+/- 5V DC

Con reason Not enough information

supplied

Limitedavailability

Notavailablefor 1 year

Sizeconstraints

Sizeconstraints

Con reason Ships fromJapan

High price

Introduction Payload Structures Thermal ADCS Conclusions

ADXRS 150Properties:• Complete rate gyroscope on a single chip• Z-axis (yaw rate) response• Self-test on digital command• 5V single-supply operation• Very light (< 0.5g)• Range: +/- 150deg/s• Sensitivity: 12.5 mV/deg/s• Temperature range: -40 to 85 C• Total chip: 7mm x 7mm x 3mm

The rate gyroscope uses Coriolis effect to sense the speed of rotation. 

Introduction Payload Structures Thermal ADCS Conclusions

ADXRS 150

Pin Configuration:

•RATEOUT: Voltage proportional to the angular rate about the axis normal to the top surface of the package

•SELF TEST FUNCTION: Works in same manner as if the gyro was subjected to angular rate.

It produces a positive going output voltage forclockwise rotation about the axis normal to the package top.

Attitude Control

Introduction Payload Structures Thermal ADCS Conclusions

Reasons for Attitude Control: Stability, Communications, Special Devices like cameras.

KEY OPTIONS

PASSIVE CONTROLACTIVE CONTROL

Magnetorquers

Control Moment Gyros

Reaction Wheels

Gravity Gradient

Permanent MagnetsHysteresis Dampers

Solar Sails

Passive Magnetic Control

Introduction Payload Structures Thermal ADCS Conclusions

X

Y

Z

•The frame XYZ is the inertial reference frame.

•Spherical-Harmonic Equations solutions for field vectors in XYZ.

•GOAL: Align satellite antenna axis with Earth’s field.

•HOW? Magnetic dipoles tend to align with an external field – lowest energy state.

τ = μ x B

Earth Magnetic Field @ 600km alt

Introduction Payload Structures Thermal ADCS Conclusions

Earth Magnetic Field @ 600km alt

Introduction Payload Structures Thermal ADCS Conclusions

Reference Frames- Attitude Dynamics

Introduction Payload Structures Thermal ADCS Conclusions

z

y

x

CCCSS

CSSSCCCSSSSC

SSCSCSCCSSCC

b

b

b

3

2

1

BIIdt

d

dt

d H

M

Roll, Pitch and Yaw Transformation

Euler’s Equation:

Coupled Differential equations:

Equations+Initial Conditions→Numerical discrete time simulation using Runge-Kutta 4, 5

yxzzyyz

zz

zxzzxxy

yy

zyyyzzx

xx

IIdt

dIM

IIdt

dIM

IIdt

dIM

3

2

1

321

21

21

C

SS

C

CS

dt

d

CSdt

d

C

S

C

C

dt

d

Ref: Wertz, Spacecraft AD and Control, Reidel 1984

Introduction Payload Structures Thermal ADCS Conclusions

Inertial Simulation – No external torques

Nm

Sm

Nm

Sm

Introduction Payload Structures Thermal ADCS Conclusions

Permanent Magnets Active

Nm

Sm

Nm

Sm

Required 90 pitch

μ = 0.2 A m2

Maximum magnet-field line offset of 11o

Attitude Control Parameters

Introduction Payload Structures Thermal ADCS Conclusions

SIMULATION PARAMETERS:

MOMENTS OF INTERTIA:

Ixx = 1.5212 x 10-3 kg m2

Iyy = 1.448 x 10-3 kg m2

Izz = 1.507 x 10-3 kg m2

SIMULATION RESULTS:

Magnet Size (moment): 0.1 to 0.5 Am2

For ALNICO-5 size: 10-30 grams

Resolution Target: within 12 O

Typical Magnet

Typical Damper

Attitude Control Future Work

Introduction Payload Structures Thermal ADCS Conclusions

• Model Hysteresis damping and incorporate in satellite dynamics

• Convert dynamical differential equations into Quaternion format (‘cleaner’ math)

• Testing of magnetic and hysteresis materials for actual properties

• Study coupled hysteresis-permanent magnet dynamics

• Study gyroscopic (precession) effects on the attitude dynamics solutions/plots.

B

H

About CubeSat- Launch Vehicle

Introduction Payload Structures Thermal ADCS Conclusions

• Launch Site: Baikonur Cosmodrome, Kazakhstan

• Launch weight 211 Tons

• Uses SS-18 liquid-fuelled ICBM

• Three-stage in-line configuration.

• 3 P-PODS: each containing 3 CubeSats

About CubeSat- Testing Requirements

Introduction Payload Structures Thermal ADCS Conclusions

Specifications required by CalPoly need to be met in order to qualify for integration and launch:

•Structural dimension and weights requirements

•Thermal-vacuum chamber testing

•Vibration testing

Electrical & Computer Engineering

Introduction Payload Structures Thermal ADCS Conclusions

• Power (Brian Vitale): – Lithium Ion Batteries– Power distribution layout

completed• Communications (Mac Mills and

Thamer Bahassan): – Antenna design– FSK transceiver

• C&DH (Jorge Moya and Elena Nogales): – Onboard data collection and

computing. – Microprocessor PIC18

Typical EE board with components

• System Constraints– Max Bus Voltage (5-7 Volts Peak)– Operating frequency (approx. 433

MHz)– Electromagnetic interference

Future Work

Introduction Payload Structures Thermal ADCS Conclusions

• PAYLOAD• Complete fabrication (CNC) & gold plating• Pressure/Temperature testing and environment testing

• STRUCTURES• Complete antenna design & deployment mechanism (Nitinol ® )• Begin CNC Aluminum fabrication of parts • Vibration, thermal and vacuum testing• Composite side panel fabrication in the Composites Lab.

• THERMAL• Thermal heater and temperature detector calibration and testing• Thermal-Vacuum environment testing

• ADCS • Implement and test gyroscopes• Incorporate damping in simulation and fix magnet sizing

Conclusions & Questions

Introduction Payload Structures Thermal ADCS Conclusions

• The interdisciplinary nature of this project is a new and exciting challenge for our team.

• Translation of analytical and design work to physical hardware and working integrated systems presents a unique challenge. Unexpected problems arise.

• Our focus on robust, well thought out design ideas, especially in the early design phase, has helped expedite our work.

• Design work is complete. Fabrication work has begun for key components and we are testing at the component and sub-system level at this time.

Special thanks to:•Dr. Benoy, Dr. Condoor, Dr. Ferman, Dr. Fitzgerald, Dr. George, Dr. Jayaram, Dr. Ravindra (AE & ME)•Mr. Frank Coffey (Parks AE & ME Labs)•Dr. Shelly Minteer and Rob Arechederra (Chemistry)•Dr. H. S. Mallik (Electrical Engineering)•Dr. Brody Johnson (Mathematics)•Ms. Jean Jackson (Parks Development)•Our freshman, sophomore & junior team members

Introduction Payload Structures Thermal ADCS Conclusions

Appendix A – Thermal Equations

4_, sunendtotalavgiavgeclipsetotaleclipse TAAGQ

40, TAAGQ totalavgiavgsuntotalsun

0_ TTmctQ sunendipsunsun i

sunendeclipseendipeclipseeclipse TTmctQi __

4_, eclipseendtotalavgiavgsuntotalsun TAAGQ

Appendix B – More Drawings

Introduction Payload Structures Thermal ADCS Conclusions

Appendix C – Thermal Expasion

Introduction Payload Structures Thermal ADCS Conclusions

o o

o o

Thermal Expansion of Structure

40 40

Aluminum 6061-O

Coefficient of Thermal Expansion

linear 68 F 23.6 m/mC

linear 250 C 25.2 m/mC

PEEK (unreinforced)

Coefficient of Thermal Expansi

o oC T C

o o

o o

9 4

on

linear 20C Average = 44.1 m/mC

linear 100C Average = 39.2 m/mC

Vertical Displacement

Aluminum components

113

0.113 23.6 10 / 80 1000 2.13 10o o

h mm

mmh CTE T m m mC C mm

m

9 4

9 4

PEEK Components

0.113 44.1 10 / 80 1000 3.99 10

Horizontal Displacement

Aluminum components

100

0.1 23.6 10 / 80 1000 1.88

PEEK Components

80

o o

o o

mmh CTE T m m mC C mm

m

l mm

mml CTE T m m mC C mm

m

l mm

h CT

9 40.0.8 44.1 10 / 80 1000 2.82o o mmE T m m mC C mm

m

Appendix D – Mass Budget

Introduction Payload Structures Thermal ADCS Conclusions

Component Density (kg/mm^3) *10^-6 Mass (kg) Quantity Component Total (kg)Battery Pack 2.06800 0.04074 4 0.16297Battery Box Bottom 2.70000 0.02025 2 0.04050Flange 2.70000 0.00152 12 0.01819Side Panel 2.70000 0.04570 2 0.09139Bolt 7.80000 0.00163 8 0.01305Nut 7.80000 0.00143 16 0.02280EE board 1.97700 0.03102 3 0.09307Bushing 1.97700 0.00008 16 0.00120Payload Tank 1.26000 0.06375 1 0.06375Phenolic Washer 1.97700 0.00003 16 0.00050Washer 7.80000 0.00003 16 0.00048Short Bolt 7.80000 0.00141 8 0.01125Fuel Cell 3.10000 0.03223 1 0.03223Magnet+ Hysterisis 0.04000Tank interface 1.26000 1 0.00600Epoxy 0.00500Wiring 0.05000MLI 0.00500Heater 1 0.01000PCB Panel 3.03000 0.02500 6 0.15000Screws 32 0.00800

Total 0.82537

Appendix E – Cross Beam Vibs

Introduction Payload Structures Thermal ADCS Conclusions

Vibration of Beam on Side Panel Paul Lemon 11/30/06

3L 10.995608 4L 14.1371651L 4.730041 2L 7.853205

A 4mm 4mmb 4mm h 4mm 2.7

g

cm3

E 70 106

kg mm

s2

A 1.6 10

5 m2

Ib h

312

I 2.133 1011 m

4

L2 E I

A L4

1

2

L

2 2L2 70 10

6 21.33

2.7 106 16 83

4

1

2

2 5.263 104

1 1L2 70 10

6 21.33

2.7 106 16 83

4

1

2

f2

2

2

1 1.909 104

f2 8.376 103

f11

2

f1 3.039 103

4 4L2 70 10

6 21.33

2.7 106 16 83

4

1

2

3 3L

2 70 106 21.33

2.7 106 16 83

4

1

2

4 1.706 1053 1.032 10

5

f44

2

f33

2

f4 2.715 104

f3 1.642 104

Singiresu S. Rao. Mechanical Vibration 4th Edition. Prentice Hall, Inc.2004

Hz

Hz

HzHz

Appendix F – Component Vibs

Introduction Payload Structures Thermal ADCS Conclusions

Pro Mechanica Hand CalculationComponent Mode Natural Frequency (Hz) Natural Frequency (Hz)

Cross Bar Beam 1 3051 3039

2 3059 8376

3 9520 16420

4 10025 27150

Support Panel 1 2747.8

2 2760.69

3 2804.42

4 2810

Battery Box 1 1459.37

2 2701.97

3 2962.99

4 3234.84