1. Team Thumbs Up Final Presentation
Edward Cyrus
Brian Inglis
Jake Varey
Greg Nelson
Nick Lenk
Chase Pritchett
12/1/08

2. Mission Overview Mission Statement:
The BalloonSat- “Optimism Prime” shall ascend to an altitude of approximately 30 km in order to measure the solar intensity as a function of altitude, the internal and external temperatures, and the humidity to better understand the conditions of “near space.” The primary science of this mission shall ascertain the reasons why solar cell technology is so prevalent in space technology. This BalloonSat shall provide the data necessary to evaluate the science goal.
Goals:
Take voltage readings from photodiodes and solar panels
Discover a correlation between altitude and voltage produced by photodiodes/solar panels
Verify predictions that solar panels produce more voltage than photodiodes
Verify prediction that light intensity increases as altitude increases
Successfully recover and analyze data from BallonSat

3. Design Overview
Three pairs of photodiodes were connected in series directly to the HOBO’s. Five solar panels were each connected directly to HOBO’s. The HOBO’s took data over the course of the flight.
A heater was placed in the interior to maintain acceptable flight temperatures.
A digital camera was used to take photos during
flight.
Many changes were made from the proposal to
the final product
Number of photodiodes stayed the same (6),
but number of solar panels went from two to five
Number of HOBOs: 2 changed to 5
Dimensions: 22 cm sides changed to 16 cm sides

4. Design Pictures

5. Analysis of the results
We predicted that the solar intensity would increase with altitude.
The results we found were different from our prediction. The solar intensity did not seem to increase with altitude nearly as much as it increased and decreased with the relative outside temperature.
Our balloonSat flight went exactly as we planned. The HOBOs recorded the data the whole flight. Only one voltage cable had an error, but the rest of our data was recorded without error.

6. Solar Cell Data
Launch
Burst
Photodiode Data
Launch
Burst

7. Cold Test Data Example
This graph shows that as temperature decreases, the efficiency of the photodiodes/solar panels increases
Applying these facts, the voltage did not increase or decrease due to altitude, it varied due to temperature changes

8. Internal Temperature
External Temperature

9. Failure Analysis One photodiode string
Graph was drastically different; The voltage exceeded the max for unknown reasons
Previous tests on same channel returned accurate results
The other channel of the same HOBO worked properly
As of this date we have not been able to reproduce this failure

10. Conclusions
Temperature is a key factor for photodiodes and solar cell with their efficiency.
Temperature is directly correlated to the performance of the solar cells and photodiodes.
We were not able to directly detect an increase in solar intensity with respect to altitude. What we are able to detect is that temperature has the most significant effect on the voltage output.

11. Lessons learned
We would not have done anything different with the experiment that we conducted.
Different results could be achieved with the use of more versatile solar panels that are capable of receiving light from a broader spectrum.
The use of a data logger which can measure lumens would show the difference in light intensity as a function of altitude.

12. Ready to Fly Again?
The payload suffered no damage from the launch, burst or landing
Payload should be kept in a safe place
No temperature restrictions down to -95˚ F
To activate
Turn heater on
Turn camera on and then flip switch back to off position

13. The Matrix Requirement Optimism Prime Completed √ … ? Under 1 Kilo
860 g √
Under $150
$10.75
Digital Camera
A570IS Canon Digital Camera
Additional Experiment
Photodiodes and Solar Panels
Foam Core
-Foam Core Structure
-Foam insulation
Metric Units
Degrees Celsius, Meters
No one getting hurt … ?

14. Monetary Budget Item Cost Quantity Total
Photodiodes (Mouser Electronics Pt. # 638-PD204-6C/L3)
$.50
12 (6 in use, 6 spare)
$6.00
HOBO Data Logger (Onset Computer Corporation Pt. # H ) * 5
Voltage Cord for HOBO (Onset Computer Corporation Pt. Cable-2.5-Stereo) 3
Insulated Aluminum Wire (Onset Computer Corporation, salvaged from extra cable)
1 Meter
Solar Cells (COSGC provided Pt. # PCB65304)
Replacement 9V Batteries 6
Desiccant (Estimated, not purchased at this time)
Estimated Shipping
$4.75 -
$10.75

15. Mass Budget Item Mass(g) Quantity Total(g) Total/Remaining Mass(g)
Digital Camera
220 ± 2 1
220
220 / 780
HOBO data logger
26.0 ± .1 5
130 ± .5
350 / 650
External Temperature Cable
9.8 ± .1
359.8 / 640.2 9V
46.4 ± .1 3
139.2 ± .1
499 / 501
Structure (Foam core cube)
112 ± 1
611 / 389
Photodiodes
.166 ± .1 6
1 ± .1
612 / 388
Solar Cells
3.5 ± .5
17.5 ± .5
629.5 / 370.5
Heating Unit
31.3 ± .1
31.3 ± 2
660.8 / 339.2
Insulation
46.2 ± .1 -
707 / 293
Voltage Cable
16.6 ± .1 8
132.8 ± .8
839.8 / 160.2
Flight Support System
28.0 ± .1
867.8 / 132.2
Desiccant
5 ± .5
872.8 / 127.2

16. Advice Decide on a timeline and stick to it.
Time can be your friend if you use it wisely. Otherwise it will be your enemy
Don’t be afraid to ask questions of other students, your teacher, or even people outside of class.
Get as much done as you can ahead of schedule so that you can have no worries on launch day.