Thermal Investigation for Accurate
Temperature Measurement
Team TCTJ
Truc Le
Cedric Toguem
Jonathan Newman
Overview
•Mission
Goal
•Objectives
•Science Background
•Technical Background
•Payload Design
• Electrical
• Software
• Mechanical
•Payload
Development
Mission Goal
The goal is to determine why previous
LaACES payloads failed to correctly
measure temperature in comparison to
NOAA.
Objectives
Measure
the temperature inside and outside
the boundary layer
Measure the temperature with different
color coated temperature sensors.
Measure the temperature on the inside and
on the outside surfaces of the payload.
Have the payload returns intact.
Temperature change in the
Atmosphere
• Troposphere
(0 to 12km) : lowermost atmosphere
where temperature decreases from 30 to -80°C
• Stratosphere (12 to 48km): second lowermost part of
the atmosphere where temperature increases from -80 to
0°C
http://apollo.lsc.vsc.edu/classes/met130/notes/chapter1/vert_temp_all.html
Boundary Layer


Thin layer of fluid in contact with a solid body that flows
more slowly than the rest of the fluid
As the payload gains altitude in fluid air, the boundary
layer around it will be affected by heat transfer
processes
http://apollo.lsc.vsc.edu/classes/met130/notes/chapter1/vert_temp_all.html
Heat Transfer Modes

Heat can be transferred in three different ways:
- Conduction
- Convection
- Radiation
http://blogs.saschina.org/morena01pd2016/files/2009/10/ccr.jpg
Conduction

Transfer of thermal energy between molecules
due to temperature gradient

The energy flows from a region of higher
temperature to a region of lower temperature
Convection

Movement of molecules within fluid

A shallow layer of air in contact with a hotter
surface warms by conduction, acquires
buoyancy and then rises
Radiation


Electromagnetic radiation emitted from the surface of
an object in the form of heat due to the objects
temperature
If an object is warmer than its surrounding environment,
it will emit more radiation in the form of heat into the
surrounding environment than it will absorb in order to
attain thermal equilibrium
http://www.tsc.com/irgen/Image7.gif
Test 1: Radiation Test 1
Radiation test:
Sun →Electromagnetic radiation → Space →Sensors
The test will consist of different color shielding to
reflect the electromagnetic radiation from the
sun
http://image.tutorvista.com/content/dispersion
Test 2: Radiation Test 2
Radiation Test:
The payload circuitry will emit radiation to the
sensor.
 Distance from the radiation source will
determine the amount of heat dissipated

http://images.google.com/imgres?imgurl=http://www.uos.harvard.edu/images/ehs/radiation
Test 3: Boundary Layer Test
Sensors are placed at different distance from
the exterior surface of the payload
 Determine how much effect the boundary layer
has on the measured temperature

http://www.google.com/imgres?imgurl=http://www.engineering.leeds
Thermal Boundary Layer
Payload Design
Power Source
BalloonSat
CPU
Op Amp
Temperature
Sensors
Electrical Design
Electrical Design (lowest level)
Power Supply
Sensors
BallonSat
Sensors
Sensor Interfacing
Sensor Interfacing
Power Supply
5V DC
temperature
Sensors
0~800mV
Op-Amp
2.5~3V
BalloonSat
(ADC)
Flight Power Supply
Flight power supply
12V battery
5V battery
Sensors
Op Amp
BalloonSat
Power Budget
Component
Current
(mA)
Duration
(hrs.)
Capacity
(mA-h)
BalloonSat
51
(measured)
4
275
RTDs (x7)
1 each
(estimated)
4
28
Total
58
4
303
Flight Software
Pre-Flight and During Flight
ADC
Sensor Data
Read
Read
BalloonSat
Write
Real Time Clock
Memory
Flight Software
Post-Flight:
Memory
BalloonSat
Read
Basic Stamp Editor
Excel
Flight Software
Onboard Flight Program:
Loop
Pause
Read
End
If/Then
Write
Flight Software
Post Flight Program:
Read
Transfer to Excel
Analyze
Exterior Mechanical Design
Interior Mechanical Design
Weight Budget
Component
BalloonSat
Styrofoam Structure
Weight (g)
66 (measured)
150 (estimated)
BalloonSat Styrofoam
Attachments
Wiring
25 (estimated)
Booms (if balsa)
Booms (if plastic)
Boom attachments
3 (estimated)
10 (estimated)
25 (estimated)
Sensors
Total
10(estimated)
289.5-296.5 +/- 25%
7.5 (estimated)
Payload Development Plan
Mechanical
◦ Boom prototyping
◦ Attachment prototyping
◦ Impact test to find best design to store
components
◦ Maintain payload within regulation
Payload Development Plan
Electrical
◦ Determine best temperature sensor to use
◦ Determine best batteries to use and its
configuration
◦ Design the circuitry of the system
◦ Determine how well the components will
function in flight climate
◦ Determine methods of calibration of the
sensors
Payload Development Plan

Software
◦ Determine best way to consume less power
◦ Determine if extra memory will be needed
and how to access it
◦ Determine the timing sequence
◦ Determine methods of calibration
Reference
1.
2.
3.
4.
Clavius: Environment - heat transfer.
http://www.xmission.com/~jwindley/heatxfer.html. November 24,
2009
Anne E. Egger "Earth's Atmosphere: Composition and
Structure," Visionlearning Vol. EAS
2003.
http://www.visionlearning.com/library/module_viewer.php?mid=1
07
Sad Dr Rodrigue – Introduction to physical Geaography.
http://www.csulb.edu/~rodrigue/geog140/lectures/thermalstructu
re.html
BASIC Stamp 2p 24-Pin Module.
http://www.parallax.com/Store/Microcontrollers/BASICStampMo
dules/tabid/134/ProductID/7/List/1/Default.aspx?SortField=UnitC
ost,ProductName. November 25, 2009
Questions?