1. PIMA COMMUNITY COLLEGE ASCEND! 2009 ASGC Symposium April 18, 2009 1

2. Students:Team: Stacy HarrisonFabrication/Integration Mike IuzzolinoFabrication/Integration Zack JarrettSoftware Peter KozakThermodynamics Chris MillerCircuits Kyle RineThermodynamics Peter SalibaCircuits Tarek TouziMisc. Roscoe VerteinFabrication/Integration Faculty:Position: Dr. Denise MeeksInstructor/Dept. Chair Mike SampognaInstructor/Mentor 2

3.  What science can we attach to a balloon that rises to 90,000 ft. ?  Measure solar radiation high above the Earth’s surface where the atmosphere is thin  Observe necessary heating mechanisms in near space 3

4.  What data should we collect?  What instrument would we use?  How does the “near space” environment affect the measurements?  Can the experiment be done within our budget?  What do we need to learn?  Stages (Fall 08 launch and Spring 09 launch ) needed to first test the concept and second complete the experiment. 4

5.  Getting started  Heater  Circuits  Software  Fabrication 5

6.  Less than 4 lbs  Power to weight ratio  Withstand extreme temperature/pressure environment found in near space 6

7. 7 OAA/D Microprocessor Data Sent Heater Stage Sensor Head Data Storage

8.  LEDs will be used to detect the sun’s radiation during the flight  Data will be collected, stored, and transmitted 8

9.  Spectrally sensitive  LED will emit light when voltage is applied but in our case, shine light and a voltage is created  Direct measure of sun’s intensity  Cost effective  BUT they don’t like low temperatures 9

10.  Responsible for figuring out:  Heating methods  Materials best suited  Responsible for construction:  Mica heater  Contact with sensors  Responsible for testing:  Heat transfer mechanism  Power requirements 10

11. 11 EfficiencyAdding heatRemoving heat Convection Conduction Radiation

12.  Thermocouple built into the LED sensor board  Heating Control  Measured ambient temp at LEDs  On – Off control circuit 12

13.  Mica heater  Conduction requires maximum contact with board  Layers of anti-static plastic were used to mold heater to circuit board 13 Steel Washer Ceramic Paper Mica Steel Washer What’s this mean anyway? What is our heating effciency at altitude

14. Hours and hours of testing went into designing and developing the heating system. 14

15.  Heater operation  Room temp  Cold temp  Room temp in vacuum  Cold temp in vacuum  Completed heater circuit  Heat up and cool down times  Understanding heater power requirements 15

16. 16 OAA/D Microprocessor Data Sent Heater Stage Sensor Head Data Storage

17. 17 Tinytrak II Modem BX24 Microprocessor Board Radio triband… Sensor Support Board LED Sensor/ Heating Board Sunfinder Board

18.  Computer  Netmedia Inc. BX24 Microcontroller  Software  Programmed using the Basic-X Language, a subset of Visual Basic 18

19.  4 Functions:  Gather data from the sensor and sun-finder platforms  Toggle the sensor platform heater  Store the data onboard  Output the data serially to the radio equipment 19

20.  Reads the LED voltage from the analog/digital converters  Repeats every 30 seconds 20

21.  Measure the voltage from the Zener diode on the sensor platform  Voltage from thermister is 10 mV to 1 Kelvin conversion  If the temperature is below 11° C, turn on the heater  When the temperature exceeds 16° C, turn off the heater 21

22.  Store the measured data (LED voltages, RC time constant values, sensor temperature, and time) in the 32 Kbytes of onboard EEPROM  Divide the data into 3 packets and transmit each packet 3 times to the radio transmitter 22

23.  Superstructure of closed-cell foam (bait box)  Low weight to volume ratio for internal space requirement  Elasticity of material for impact absorption  Infrastructure of open-cell foamboard  Lightweight  Rigid  Easy to handle and cut 23

24.  A hardpoint is a rigid connection between structure and payload; a firm point is a non-rigid connection allowing for a cushion between internal and external components.  Circuit boards were attached via individual mounting rigs  Nylon machine screws and nuts fastened rigs 24

25.  Open-celled foamboard structure designed around circuit sizes and placement requirements 25

26.  Wrapped in duct tape for fibrous reinforcement of superstructure 26

27.  Current status  Fabrication technique worked  Data being analyzed  Circuits performed as expected  Heater performed as expected  Conclusion  2 campuses  Students 2 – 8  Many more skills added 27

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