BillikenSat-II The First Bio-Fuel Cell Test Platform in Space Darren Pais Paul Lemon Nathaniel Clark Sonia Hernandez Brian Vitale Jorge 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 Enzymes V Anode Cathode H+H+ Nafion 112 H+H+ O2O2 H2OH2O e-e- 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 CathodeAnode 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 irradiation absorptivity incident area emissivity Stefan-Boltzmann const. radiating area temperature at time-step t

Thermal Environment Introduction Thermal Structures ADCS EE Conclusions Structural Temperature Range: -20 o C to 35 o C

Payload Protection Introduction Thermal Structures ADCS EE Conclusions Multi-Layer Insulation (MLI) Structural Temperature Range: -20 o C to 35 o C Payload Survivable Range: 4 o C to 40 o C Thermal conductivity of PEEK eliminates conduction effects MLI eliminates radiation effects 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 < 10 o C If T > 30 o C take no action turn on heater turn off heater true false true

Assembly Introduction Thermal Structures ADCS EE Conclusions Common fasteners used throughout Component positions interchangeable Side Rail Battery Box Payload 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 StressMount DisplacementMount Displacement Scale Max rail stress: MPa Max Deflection: 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: Nitinol shape memory alloy

Introduction Thermal Structures ADCS EE Conclusions NmNm SmSm orbit Communication Window NmNm SmSm orbit Geo-Magnetic Lines of Force Passive Control using Permanent Magnets and Hysteresis Dampers Attitude Control

Introduction Thermal Structures ADCS EE Conclusions Attitude Control b 2 (hysteresis axis) b 3 (permanent magnet axis) b 1 (hysteresis axis) BRF O

Introduction Thermal Structures ADCS EE Conclusions Roll, Pitch & Yaw

Introduction Thermal Structures ADCS EE Conclusions Attitude Control Parameters Typical Magnet Typical Damper SIMULATION PARAMETERS: MOMENTS OF INTERTIA: I 1 = x kg m 2 I 2 = x kg m 2 I 3 = x kg m 2 SIMULATION RESULTS: Permanent Magnet (ALNICO-5): 0.1 Am 2, 35 grams Hysteresis Damper (HyMu80): 15 grams Resolution Target: within 10 0

Orbital Elements Introduction Thermal Structures ADCS EE Conclusions Orbital ParametersDNEPR 07 Type of OrbitSun synchronous Inclination98 deg Eccentricity0.009 Altitude Perigee660 km Altitude Apogee772 km Period90 min 1: P-POD 2: - DNEPR Launch Vehicle - Location: Baikonur, Kazakhstan 3: Two Line Elements provided by NORAD

Attitude Determination Introduction Thermal Structures ADCS EE Conclusions 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 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 Introduction Thermal Structures ADCS EE Conclusions Power Gyro PIC 5V Vdrive D out 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&DH PIC 18 Micro- controller Power Battery Array Battery Chargers Solar Array 5V7V3.3V ADCS Thermal Control Experiment Experiment Communications 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 GroundStation 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 VddVref ICD Digital(5) PIC 18 Payload Thermal Switches Battery voltage Pressure sensor Thermo couple On/Off ADCS Rate Gyros

Communications Introduction Thermal Structures ADCS EE Conclusions Antenna T/R Switch Band Pass Filter Melexis TH7122 Transceiver External IF IC Band Pass Filter RF Power Amplifier Standard FSK VCO FSK Generator Microprocessor TX/Rx Rx TX Rx 10.7 MHz Approx 433 MHz Ground Station FSK Radio 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-DC Converter ≈3.3V DC-DC Converter ≈5V DC-DC Converter ≈9V Rate Gyro X Rate Gyro Y Rate Gyro Z Microprocessor Multiplexer Antenna Power Amplifier Transceiver Active Thermal Control Payload Monitoring System CDH Power PayloadADCSCommunications

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 Analysis RiskBefore MitigationAfter Mitigation LikelihoodConsequenceLikelihoodConsequence Launch vehicle failure Antenna deployment failure Payload Experiment Failure LEO Environment SevereModerateMinimalKEY:

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

Questions Thank 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 cm 2 Comparison: A cell phone on average draws 200 mW With flow: 20 mW/cm 2 is possible  Cell the size of a small book can power a laptop Introduction Thermal Structures ADCS EE Conclusions

Appendix II: Versatility Energy Density (Whr/L) Fuel Versatility Components of Bio-Fuels Alkaline Lithium Ion Liquid Hydrogen Introduction Thermal Structures ADCS EE Conclusions

Appendix III: Risk Matrix Introduction Thermal Structures ADCS EE Conclusions

Appendix IV: I2P Versatile Design Can be scaled easily Versatile Fuel Selection Designed to maximize fuel choice Introduction Thermal Structures ADCS EE Conclusions

Appendix V: Facilities 1. 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 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 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 tested 1.) Teflon tape 2.) Super glue 3.) 90 second epoxy 4.) 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: Radiation Risk 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 block some incoming radiation Memory duplication MaterialDamage Threshold (Rad) Biological Matter 10 1 —10 2 Electronics 10 2 —10 6 Lubricants, hydraulic fluid 10 5 —10 7 Ceramics, glasses 10 6 —10 8 Polymeric material 10 7 —10 9 Structural metals 10 9 —10 11 Van Allen Belts Introduction Thermal Structures ADCS EE Conclusions

Appendix X: 3 view and dimensions Electronic Boards Battery Box Payload Introduction Thermal Structures ADCS EE Conclusions