Thomas Buck, Kyle Garner, Alexandra Jung, Quinn Mcgehan, Mark Sakaguchi,

and Scott Taylor

Team Solkraft

Launch Readiness Review 10/7/2010

Mission Overview• Objective

– To determine the effect of near space conditions on solar cell output.• Temperature, light intensity, and altitude.

– Expect to prove that there is a relationship between the variables above and the output of two different types of cells.

• Hypothesis– The monocrystalline cells will outperform the polycrystalline cells,

while both cells will perform better in near space than on the ground.

Mission Design

Mission Design: How?• Experiment will incorporate three main categories

– Photodiodes: Detect light intensity to determine the “amount” of sunlight hitting the panels

– Thermistors: On each face to detect temperatures effect on output.

– Solar cells: Two different types to determine which one is most efficient

• All three components will be flowed into multiplexer– Multiplexer will deliver multiple logs per minute– Arduino will log results to MicroSD card to be uploaded

into Excel

Monocrystalline Cell

Polycrystalline Cell

HOBO External Temp Sensor

HOBO (Velcroed to wall of Balloonsat)

Camera

Arduino (Velcroed to wall of Balloonsat)

Heater

Multiplexer (Later moved to fit directly on top of Arduino)

Photodiode

Thermistor

Switches

Mission Design 3 9V

Batteries Switch Heater

Batteries Switch Camera 2 GB Memory Card

Multi-plexer

Thermisters

Photodiodes Polycrystalline Solar Cells

Monocrystalline Solar Cells

Batteries Switch Arduino 328

1GB Micro SD Card

HOBOPower

Switch

Provided Hardware

Sensors

Solar Cells

Testing• Tests performed

– All Structure tests– Cold test– Sensor testing: make sure all sensors are putting out reasonable and

consistent values.– Integrations test: doing a mission run on the ground to make sure

everything is recording– Control Test: starting to analyze which how temperature affects solar

cells on the ground. Still need to perform more control tests before launch.

Science Testing

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Voltage Readings of Solar Cells by Arduino

MonocrystallinePolycrystalline

Time (s)

Volta

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Moved box into the shade

General systems test in low light. Readings from one side of the BalloonSat

Cold Test Temp (Thermistors)

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Time (seconds)

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Side 2

TIme (seconds)

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ture

(Cel

sius)

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Side 3

Time (seconds)

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sius)

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Side 4

Time (seconds)

Tem

pera

ture

(Cel

sius)

Cold Test Temp (HOBO)

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1. Cold test with dry ice covered

2. Cold test with dry ice uncovered BallonSat

3. Cold test in freezer

Structure Testing (Drop Test)

Structure Testing (Stair Test)

Structure Testing (Whip Test)

Expected Flight Results

• Monocrystalline will produce more voltage than the polycrystalline solar cells.– Research and initial testing both indicate

monocrystalline produces more voltage with a similar surface area.

Expected Flight Results

• Both types of solar cells will produce more power in near space due to:– Higher light intensity

• Less interference with atmosphere, meaning more photons of light per area hitting the sensors.

– Solar cells are less effective at higher temperatures• Higher Carnot efficiency of the cell

• Assuming lower temperature and higher light intensity increase voltage output, we can determine which has greater affect by seeing whether the peak voltage is in the tropopause or at maximum altitude.

Biggest Worries• The Biggest Worries Of Team Solkraft Are…

– Camera failure incl. camera fogging up– Hardware failure i.e. solar panels breaking– Lack Of Sleep

Mission Requirements (Level 0)

Requirement Number

Requirement Where it comes from

M 0.1 The solar panels on the BalloonSat shall be exposed to near-space conditions

Mission Objective

M 0.2 Team Solkraft shall measure the internal and external temperature with varying altitude

Mission Objective

M 0.3 Team Solkraft shall measure the light intensity with varying altitude

Mission Objective

M 0.4 Team Solkraft shall test for variations in solar cell output under varying climate conditions

Mission Objective

M 0.5 Team Solkraft shall meet the requirements for the request for proposal

Mission Requirements (Level 1)

Requirement Number

Requirement Where it comes from

M 1.1 The solar panels shall be attached to the angled sides of the BalloonSat

M 0.1 M 0.4

M 1.2 Team Solkraft shall be able to record the altitude of the BalloonSat using data from EOSS GPS

M 0.2, M 0.3

M 1.3 Team Solkraft shall be able to record and save data during the flight

M 0.2, M 0.3, M 0.4

M 1.4 Team Solkraft shall maintain a minimum temperature of -10 degrees Celsius.

M 0.3, M 0.3, M 0.5

M 1.5 Team Solkraft shall program the Arduino microcontroller to record solar cell output data to a micro SD card

M 0.2, M 0.3, M 0.4

M 1.6 Team Solkraft shall take in-flight pictures using a Canon A5701S camera and save them to the camera’s 2 GB memory card.

M 0.5