BillikenSat-II
The First Bio-Fuel Cell Test Platform in Space
Darren Pais
Paul Lemon
Nathaniel Clark
Sonia Hernandez
Presentation at the AIAA Region V Student Conference
US Air Force Academy, Colorado Springs, CO
April 12-13, 2007
Biofuel Cell Technology
V
e-
Enzymes
Anode
e-
O2
H+
H+
H2O
Nafion 112 Cathode
Enzyme catalyzed bio-reaction that produces power in a manner similar to a
hydrogen fuel cell or an alkaline battery
The Idea
Payload
Structures
Control
Conclusions
In space?
Astronaut
drinks water
Human waste
is used in
bio fuel cell
Bio-Cycle
Fuel cell
produces
power and water
GOAL: Proof of concept
?
The Idea
Payload
Structures
Control
Conclusions
CHALLENGES:
• Sizing – Volume, mass
• Pressure Regulation
• Temperature Regulation
• Experimental Verification
Payload
• Able to utilize variety of fuels
• Smaller, lighter flight version
• Large fuel reservoir, resists corrosion
• Good conduction between plates:
Gold plating, 4 bolts
Cathode
Cathode
Anode
CAD Model
Membrane Electrode
Assembly (MEA)
Anode
4 cm
Finished Anode
The Idea
Payload
Structures
Control
Conclusions
Payload
Air Tight Fill Port
Wire Interface
The Idea
Payload
Structures
Control
Conclusions
Temperature Control
Survivable range: 4oC < T < 40oC
temperature
sensor
true
turn on
heater
If T < 10oC
false
true
If T > 30oC
false
turn off heater
take no action
The Idea
Payload
Structures
Control
Conclusions
Thermal Analysis
Satellite Temperature Range:
Multi-Layer Insulation (MLI)
-38oC to 50oC
q
• Thermal conductivity of PEEK
eliminates conduction effects
Dacron Web
• MLI eliminates radiation effects
Mylar Film
Heating/Cooling Cycle:
qe
Heater on ~ 14 minutes
Heater off ~ 18 hours
The Idea
Payload
Structures
1
q  qe
n 1
Control
Conclusions
Assembly
Battery Box
Side Rail
Payload
Antenna
• Common fasteners used throughout
• Component positions interchangeable
The Idea
Payload
Structures
Control
Conclusions
Antenna
Antenna: Nitinol
shape memory alloy
Nylon & Nichrome
for deployment
Spiral
etching
Silver epoxy
for contact
The Idea
Payload
Structures
Control
Conclusions
CAD  Hardware
1. CAD
2. FEM
• Strain tests on structure
• Compare results
• Ensure Margin of Safety
3. Hardware
The Idea
Payload
Structures
Control
Conclusions
Attitude Control
Nm
Nm
Communication
Window
orbit
Sm
orbit
Sm
Geo-Magnetic Lines of Force
Passive Control using Permanent Magnets and Hysteresis Dampers
The Idea
Payload
Structures
Control
Conclusions
Attitude Control
b3 (permanent magnet axis)
BRF
O
b2 (hysteresis axis)
b1 (hysteresis axis)
The Idea
Payload
Structures
Control
Conclusions
Roll, Pitch & Yaw
The Idea
Payload
Structures
Control
Conclusions
Orbital Analysis
The Idea
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
Payload
Structures
• 4 communication windows per day
• 4-7 minutes per communication window
Control
Conclusions
Electronic Interfaces
Ground
Station
ADCS
Rate Gyro X
Communications
Antenna
C&DH
PIC 18
Microcontroller
Rate Gyro Y
Power Amp
Rate Gyro Z
Transceiver
Power
Solar Array
Experiment
Thermal Control
Heater
Battery
Chargers
A/D Conv.
Control Switch
Battery Array
Control Switch
Thermal Sensor
3.3V
5V
7V
Data
Unregulated Bus
3V Bus
5V Bus
7V Bus
The Idea
Payload
Structures
Control
Conclusions
System Interfaces
Legend
Structures
ADCS
Power
C&DH
Comm.
C&DH
Thermal
Electrical Engineers: 3
Computer Engineers: 2
Aerospace Engineers: 4
Chemistry: 1
The Idea
Payload
Structures
Control
Conclusions
Risk Analysis
Risk
Before Mitigation After Mitigation
Likelihood
Consequence
Launch vehicle failure
Antenna deployment
failure
Payload Experiment
Failure
LEO Environment
KEY: Severe
The Idea
Payload
Moderate
Structures
Control
Minimal
Conclusions
Likelihood
Consequence
Conclusions & Questions
• 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
Thank You
Advisors: Dr. Jayaram, Dr. Ravindra & Dr. George
Friends and Colleagues at Parks College and the Dept. of Chemistry
The Idea
Payload
Structures
Control
Conclusions
Appendix I
BillikenSat-II: 20 mW for 16 cm2
Comparison: A cell phone on average draws 200 mW
With flow: 20 mW/cm2 is possible  Cell the size of a small book can
power a laptop
The Idea
Payload
Structures
Control
Conclusions
Appendix II
Fuel Versatility
Components of Bio-Fuels
12000
8000
6000
4000
2000
The Idea
Payload
Structures
Control
Conclusions
G
ly
ce
ro
l
Bi
od
ie
se
l
l
Et
ha
no
ga
rs
Su
no
l
et
ha
M
hy
dr
og
en
Ur
ea
qu
id
Li
Li
th
iu
m
io
n
e
0
Al
ka
lin
Energy Density (Whr/L)
10000
Appendix III
The Idea
Payload
Structures
Control
Conclusions
Appendix IV: I2P
Versatile Design
Can be scaled easily
Versatile Fuel Selection
Designed to maximize fuel choice
The Idea
Payload
Structures
Control
Conclusions
Appendix V: Facilities
1. Ground Station
2. Clean Room
• Vertical Flow
• Soft Wall
• Software: NOVA
• Antenna:
Model 436CP42 U/G Yagi
Beam-width 21° circular
The Idea
Payload
Structures
Control
Conclusions
Appendix VI: Vibrations
Mode 1 Shape
Mode 2 Shape
•First natural frequency falls within range of frequencies
expected on launch
• Deflections are 0.00116 mm
Introduction
Payload
Structures
Thermal
ADCS
Conclusions
Appendix VII: Mass Budget
• Total mass estimated to be 825 gram
• 175 grams available for contingency
Sub System
Structure
ADCS
Electrical
Payload
Thermal
TOTAL
Thermal
2%
Payload
12%
Mass (g)
362
40
306
102
15
825
Structure
44%
Electrical
37%
ADCS
5%
Introduction
Payload
Structures
Thermal
ADCS
Conclusions
Electrical System Specifications
Command & Data Handling
Power
•PIC 18 microprocessor
•4 – 3.7V Li-ion batteries
•512 MB micro SD card
•1.2 Ampere battery charger
•Triplicate data storage
•Spectrolab Triple Junction Solar
Cells (GaInP2/GaAs/Ge)
•26% BOL efficiency
Communications
•Vmax = 2.275, Imax = 550 mA
per cell
•Transmitting at 433 MHz
•2 quarter-wave whip
antennas (redundancy)
•AX.25 protocol
The Idea
•Max power use = 2.29 W
Experiment
•Melexis power amplifier
•Potentiometer
•Transceiver, half-duplex
•Ammeter
Payload
Structures
Control
Conclusions