BillikenSat-II The First Bio-Fuel Cell Test Platform in Space

Darren PaisPaul LemonNathaniel ClarkSonia HernandezBrian VitaleJorge Moya

Final Presentation for Aerospace Engineering Senior Design Parks College of Saint Louis University, Saint Louis, MO

April 24, 2007

Agenda for Today

Introduction Thermal Structures ADCS EE Conclusions

• Overview of CubeSat and our Experiment

• Thermal Analysis

• Structures & Integration

• Attitude Control & Orbital Analysis

• Electrical & Computer Engineering

Special emphasis on the Systems Engineering aspects

What is CubeSat?

Introduction Thermal Structures ADCS EE Conclusions

• Program run by CalPoly, launch $40, 000

• Key Constraints: Cube of Side 10 cm and mass 1 kg

• CubeSat P-POD Rocket launch

• Need to meet requirements: Launch vibration and static loads,

thermal-vacuum testing, AMSAT guidelines

Bio-Fuel Cells

Introduction Thermal Structures ADCS EE Conclusions

Enzy

mes

V

Anode Cathode

H+

Nafion 112

H+

O2

H2O

e-e-

GOAL: Proof of concept

CHALLENGES: • Sizing – Volume, mass• Pressure Regulation• Temperature Regulation• Experimental Verification

?

Payload

Introduction Thermal Structures ADCS EE Conclusions

CAD Model

Cathode Anode

Anode

Membrane Electrode Assembly (MEA)Cathode

• Able to utilize variety of fuels

• Smaller, lighter flight version• Large fuel reservoir, resists corrosion• Good conduction between plates:

Gold plating, 4 bolts

Finished Fuel Cell

4 cm

Payload

Introduction Thermal Structures ADCS EE Conclusions

Air Tight Fill Port

Wire Interface

Thermal Analysis

Introduction Thermal Structures ADCS EE Conclusions

:

:

:

:

iA

G irradiation

absorptivity

incident area

emissivity

:

:

:

t

r

T

A

Stefan-Boltzmann const.

radiating area

temperature at time-step t

4tri TAAGq

tp

t Tmc

tqT

1

Thermal Environment

Introduction Thermal Structures ADCS EE Conclusions

Structural Temperature Range: -20oC to 35oC

Payload Protection

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1

1

nqq e

Multi-Layer Insulation (MLI)

Structural Temperature Range:

-20oC to 35oC

Payload Survivable Range:

4oC to 40oC

• Thermal conductivity of PEEK eliminates conduction effects

• MLI eliminates radiation effects

eq

q

Mylar Film

Dacron Web

Active Thermal Control

Introduction Thermal Structures ADCS EE Conclusions

Heating/Cooling Cycle:

Heater on ~ 14 minutes; Heater off ~ 18 hours

temperature sensor

If T < 10oC

If T > 30oC

take no action

turn on heater

turn off heater

true

false

false

true

Assembly

Introduction Thermal Structures ADCS EE Conclusions

• Common fasteners used throughout• Component positions interchangeable

Side RailBattery BoxPayload

Antenna

FEA

Introduction Thermal Structures ADCS EE Conclusions

Finite Element Analysis• Stress Applied << Ultimate Stress• Displacement less than 0.1 mm• Resonant frequencies: Panels & Battery Box• Displacement due to vibrations is minimal

• Minimum F.O.S. = 2 Battery Box Displacement

Rail Stress Mount Displacement Mount Displacement Scale

Max rail stress: 1.452 MPa

Max Deflection: 0.028 mm

CAD Hardware

Introduction Thermal Structures ADCS EE Conclusions

• Strain tests on structure• Compare results• Ensure Margin of Safety

1. CAD

2. FEM

3. Hardware

Antenna

Introduction Thermal Structures ADCS EE Conclusions

Nylon & Nichrome for deployment

Spiral etching

Silver epoxy for contact

Antenna: Nitinolshape memory alloy

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Nm

Smorbit

Communication Window

Nm

Smorbit

Geo-Magnetic Lines of Force

Passive Control using Permanent Magnets and Hysteresis Dampers

Attitude Control

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Attitude Control

b2 (hysteresis axis)

b3 (permanent magnet axis)

b1 (hysteresis axis)

BRF

O

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Roll, Pitch & Yaw

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Attitude Control Parameters

Typical Magnet

Typical Damper

SIMULATION PARAMETERS:MOMENTS OF INTERTIA:

I1 = 1.476 x 10-3 kg m2

I2 = 3.177 x 10-3 kg m2

I3 = 3.129 x 10-3 kg m2

SIMULATION RESULTS:Permanent Magnet (ALNICO-5):

0.1 Am2, 35 grams

Hysteresis Damper (HyMu80):

15 grams

Resolution Target: within 100

Orbital Elements

Introduction Thermal Structures ADCS EE Conclusions

Orbital Parameters DNEPR 07

Type of Orbit Sun synchronous

Inclination 98 deg

Eccentricity 0.009

Altitude Perigee 660 km

Altitude Apogee 772 km

Period 90 min

1: P-POD

2: - DNEPR Launch Vehicle - Location: Baikonur, Kazakhstan

3: Two Line Elements provided by NORAD

Attitude Determination

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

AD: Gyroscopes

Introduction Thermal Structures ADCS EE Conclusions

Gyroscopes determine at what rate the satellite is turning

Properties:• ADIS 16100• SPI digital output interface• Z-axis (yaw rate) response• 5V single-supply operation• Very light (< 0.5g)• Range: +/- 300 deg/s• Sensitivity: 4.1 LSB/deg/s• Temperature range: -40 to 85 C• Total chip: 7mm x 7mm x 3mm• Coriolis effect to sense speed of rotation

AD: Gyroscopes

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Power Gyro PIC 5V

Vdrive

Dout

SCLK

CS

• RATE-OUT: Voltage proportional to the angular rate about the axis normal to the top surface of the package

Introduction Thermal Structures ADCS EE Conclusions

C&DHC&DHPIC 18Micro-

controller

PowerPower

Battery Array

Battery Chargers

Solar Array

5V 7V3.3V

ADCSADCS

Thermal ControlThermal Control ExperimentExperiment

CommunicationsCommunications

Rate Gyro X

Rate Gyro Y

Rate Gyro Z

Heater

Thermal Sensor

Control Switch

Transceiver

Power Amp

Antenna

Control Switch

A/D Conv.

Data

Unregulated Bus

3V Bus

5V Bus

7V Bus

Ground Ground StationStation

Electrical Interfaces

Command & Data Handling

Introduction Thermal Structures ADCS EE Conclusions

EEPROM &microSD

COMM

Structure

SPI

R/T switch

Rx

Tx

Antenna

Kill switch

R.B.F.

Power

Vdd Vref

ICDDigital(5)

PIC 18

Payload

Thermal

Switches

Battery voltage

Pressure sensor

Thermo couple

On/Off

ADCSRate Gyros

Communications

Introduction Thermal Structures ADCS EE Conclusions

Antenna

T/R Switch

Band Pass Filter Melexis

TH7122Transceiver

ExternalIF IC

Band PassFilter

RF PowerAmplifier

StandardFSKVCO

FSKGenerator

Microprocessor

TX/Rx

Rx

TX

Rx IF @ 10.7 MHz

Approx433 MHz

Ground Station

FSKRadio Waves

433 MHz

Antenna Switch

Power

Introduction Thermal Structures ADCS EE Conclusions

Solar Array

Charge Pump

Charge Bypass

Battery Charger 1

Battery Charger 2

Battery 1

Battery 2

Battery 3

Battery 4

DC-DCConverter

≈3.3V

DC-DCConverter

≈5V

DC-DCConverter

≈9V

Rate Gyro X

Rate Gyro Y

Rate Gyro Z

Microprocessor

Multiplexer

Antenna

Power Amplifier

Transceiver

Active Thermal Control

Payload Monitoring System

CDH

Power

Payload ADCS Communications

Introduction Thermal Structures ADCS EE Conclusions

System Interfaces

C&DH

Structures

ADCS

Power

Comm.

C&DH

Thermal

Legend

Seniors Involved

Electrical Engineers: 3

Computer Engineers: 2

Aerospace Engineers: 4

Graduate Student

Chemistry: 1

Introduction Thermal Structures ADCS EE Conclusions

Risk AnalysisRisk Before Mitigation After Mitigation

Likelihood Consequence Likelihood Consequence

Launch vehicle failure

Antenna deployment failure

Payload Experiment Failure

LEO Environment

Severe Moderate MinimalKEY:

Introduction Thermal Structures ADCS EE Conclusions

Conclusions

Bio-Fuel cells constitute novel and innovative

power concepts for space applications

BillikenSat-II will illustrate the viability of Bio-

Fuel cells in space

Interdisciplinary work is challenging, but

presents a great learning opportunity

‘System Engineering’ and integration

challenges are most difficult to overcome

cubesat.slu.edu

QuestionsThank You!

Advisors: Dr. Jayaram, Dr. Ravindra, Dr. George,

Dr. Mitchell, Dr. Condoor, Dr. Fitzgerald,

Dr. Ferman & Dr. Minteer

EE Team: Elena Nogales, Justin Kerber,

Mac Mills & Thamer Bahassan

Parks Labs: Mr. Frank Coffey, Mr. Emile Damotte

Graduate Student: Rob Arechederra

Juniors: Ben Corrado & Yusshy Mendoza

Sophomores: Rehan Refai & Danny Rooney

Freshmen: Morgan Quinley & Brandon Smith

Financial Support: Aerospace Engineering, Electrical

Engineering, ASSLU-SGA & Parks AIAA

Introduction Thermal Structures ADCS EE Conclusions

cubesat.slu.edu

Appendix I: Sample Results

BillikenSat-II: 20 mW for 16 cm2 Comparison: A cell phone on average draws 200 mWWith flow: 20 mW/cm2 is possible Cell the size of a small book can power a laptop

Introduction Thermal Structures ADCS EE Conclusions

Appendix II: Versatility

0

2000

4000

6000

8000

10000

12000

Alkalin

e

Lithiu

m io

nUre

a

Liqui

d hyd

rogen

Met

hanol

Sugars

Ethan

ol

Glyce

rol

Biodie

sel

Ene

rgy

Den

sity

(W

hr/L

)

Fuel VersatilityComponents of Bio-Fuels

Alkal

ine

Lithiu

m Io

n

Liquid

Hyd

rogen

Introduction Thermal Structures ADCS EE Conclusions

Appendix III: Risk Matrix

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Appendix IV: I2PVersatile Design

Can be scaled easily

Versatile Fuel SelectionDesigned to maximize fuel choice

Introduction Thermal Structures ADCS EE Conclusions

Appendix V: Facilities1. Ground Station 2. Clean Room

• Software: NOVA

• Antenna:

Model 436CP42 U/G Yagi

Beam-width 21° circular

• Vertical Flow

• Soft Wall

Introduction Thermal Structures ADCS EE Conclusions

Appendix VI: Vibrations

Pro MechanicaComponent Mode Natural Frequency (Hz)

Cross Bar Beam 1 30512 30593 95204 10025

Support Panel 1 2747.82 2760.693 2804.424 2810

Battery Box 1 1459.372 2701.973 2962.994 3234.84

Solar Panels 1 1282

Solar Panel Mode 1 Deflection ~1.16x10-3 mm

Battery Box Mode 1 Deflection << 1mm

Introduction Thermal Structures ADCS EE Conclusions

Appendix VII: Mass Budget• 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

Introduction Thermal Structures ADCS EE Conclusions

Appendix VIII: Pressure Test

Test•Dry ice place in test chamber, sealed with wire plug•4 types of thread sealant tested1.) Teflon tape 2.) Super glue 3.) 90 second epoxy4.) Half hour epoxy

Results• Half hour epoxy completely sealed wire interface,even for liquid nitrogen cold test• All thread sealing methods proved inadequate

Conclusion - Remove plug from design, replace with holes for wires directly into tank

90 second epoxy

Bubbles from threads

No leak from wires

Introduction Thermal Structures ADCS EE Conclusions

Appendix IX: RadiationRisk• Several sources of radiation• Can cause bit flips in memory• Degrades materials• Damages solar cells• ~ 3 Rad/day expected

Mitigation• LEO shielded by Earth’s Magnetic field• Sun currently near minimum solar activity in cycle• Short experiment finishes before affects accrue• Exterior panels lined with dense copper to blocksome incoming radiation• Memory duplication

Material Damage Threshold (Rad)Biological Matter 101—102

Electronics 102—106

Lubricants, hydraulic fluid 105—107

Ceramics, glasses 106—108

Polymeric material 107—109

Structural metals 109—1011

Van Allen Belts

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Appendix X: 3 view and dimensions

Electronic Boards

Battery Box

Payload

Introduction Thermal Structures ADCS EE Conclusions