Transcript CDR Presentation

THE AVENGERS
Measuring Atmospheric
Ozone gases
General



The primary goal of the
ITO sensor project is to
measure the concentration
of Ozone (O3) as a function
of altitude.
The concentration of these
gases will specify the
current situation of ozone
depletion.
These measurements will
be compared to past
measurements made by
other payloads.
Science


The ozone layer is the
layer in Earth’s atmosphere
which contains relatively
high concentrations of
ozone. This layer contains
over 91% of the ozone in
Earth’s atmosphere. It is
mainly located in the lower
portion of the stratosphere,
from approximately 10 km
to 50 km above Earth.
Halogens, the chemical
family containing fluorine,
chlorine, bromine, and
iodine, have the ability to
catalyze ozone breakdown.
Technical


The concentration of
Ozone gases is
calculated as the
function of voltage
produced across the ITO
sensor.
As the resistance in the
ITO sensor varies with
the concentration of
these gases, different
voltages are produced
with the same amount of
input current in the
circuit board.
System Design
 Twelve volt supply powers
all sensors
 Two thermistors, two ITO
sensors, four channels
 Readings feed into ADC
channels
 ADC sends data to
BalloonSat EEPROM
 BasicStamp EEPROM also
communicates with the
BalloonSat EEPROM
Electrical Design and
Development
Sensors/Sensor Interfacing
Control Electronics
Power Supply
Power Budget
Electrical Development Plan
Sensors
ITO
THERMISTORS
Measures Ozone based on resistance
across the sensor.
As ozone increases, resistance increases.
Provided by Dr. Patel of the University of
North Florida
Two 1k Ohm thermistors.
Measures temperature based off the
resistance across the thermistor.
As temperature decreases, resistance
increases.
Sensor Interfacing
Control Electronics
Power Supply
Power Budget
Software Design
Data Format and Storage
Flight Software
Software Development Plan
Data Format and Storage


BalloonSat EEPROM
will store all data
collected on flight
(Yellow Circle)
BasicStamp EEPROM
stores addresses for
flight software (Red
Circle)
Byte #
0
1
Data Stored
Original Address
Current Address
0
1
2
3
4
5
6
7
Counter
Hour
Minute
Second
ITO Sensor 1
ITO Sensor 2
Thermistor 1
Thermistor 2
N/A
N/A
N/A
N/A
1
2
0
3
Flight Software


Read “original address”
from BasicStamp EEPROM
Add counter to data
– 1 byte

Read RTC
– 3 bytes

Read both thermistors and
both ITO sensors
– 4 bytes



Store all data from reading
Store current address in
BasicStamp EEPROM
Repeat loop until current
address equals the original
address
– (current_address =
original_address)
– LED flashes once per second
Software Development Plan



Prototyping Software
– Software must run without
glitches
– Software must successfully
record correct data from input
sensors
 Data must be saved in a
way that it will not be
overwritten
– Once software is completely
functional, it will be optimized
– Software will be uploaded to
Excel, so it must be formatted
Prototyping Hardware
– Electronics and Mechanical
aspects should work with
software
– Temperature and Pressure
Tests
Flowcharts
– As the code is written and
refined, flowcharts will be
updated
Mechanical Design
A
hollow regular
hexagonal prism
FOAMULAR Insulating
Sheathing
External Design:
Each
side of the base
= 94 mm
The height of the
prism = 175 mm
51mm X 49mm
rectangular hole for the
ITO sensor
The ITO sensor
attached from the inner
walls; minimal area of
the ITO sensor is
exposed
The external design of ITO sensor payload (in
mm)
Internal Design:



Rectangular- shaped foam
(thickness = 18 mm)
bisects the internal
payload in two
– Batteries, ITO sensor
and Nichrome heater
– BalloonSAT
Two chambers have
different temperatures
Nichrome wire attached to
the back of the sensor
with thermal paste
Internal Divider with BalloonSAT (in mm)
a) Side where ITO sensor is attached
(in mm)
b) Side where ITO sensor is attached with
ITO sensor (in mm)
Weight Budget:


S.
N.
Balloon payload should be less that 500 g
Density of The FOAMULAR Insulating Sheathing = .029 g/ cm3
Components
Weight (gram)
Clearance (g)
1.
BalloonSAT
60.4
+/- 10
2.
FOAMULAR Insulating
Sheathing
115
+/- 20
3.
Power Supply (Battery)
121.9
+/- 25
4.
ITO sensor and PCB
6.1
+/- 2
5.
Components for Sensor
Interface
35
+/- 15
6.
Mass of cable for ITO
sensor
17
+/- 3
355.4
+/- 75
Total:
Risk Assessment Matrix
Looking Ahead
 Critical
Design
Review due
3/30/2010
 Liftoff!
(Palestine):
5/25/2010
Special Thanks
Dr. Nirmalkumar Patel