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

and Scott Taylor

Team Solkraft

Critical Design 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 Overview

• Widespread development of solar cells for consumer use is relatively new– 2008- World record set in efficiency (40.8%)

• Very expensive cell, not consumer friendly– Two main types of consumer oriented cells

• Monocrystalline/Polycrystalline • Why?

– Want to know which type of cell is more efficient for consumer use

– Want to know which environments are best for maximum energy output

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

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 Matlab/Excel

Mission Design

ArdunioHOBO

Mono Cells

Poly Cells

Photodiodes

Thermistors

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

2GB Micro SD Card

HOBOPower

Switch

Provided Hardware

Sensors

Solar Cells

Test Plan• Structure Tests

– Kick Test– Drop Test– Whip Test

• Freeze Test to make sure thermal systems work• Data Test to make sure Arduino and HOBO are recording properly• Camera/Imaging Tests• Ground Control Tests for:

– Solar Panels– Photodiodes– Thermistors

Expected Results

• Monocrystalline will outperform polycrystalline solar cells

• Solar cells will produce more power in near space– Higher light intensity

• Less interference with atmosphere– Solar cells less effective at higher temperatures

• Higher Carnot efficiency of the cell

Organization

Scott Taylor Team Lead Structure

Lead Science Assist

Kyle Garner Power Lead

Internal Testing Data Analysis

Thomas Buck Science Lead

Science Testing Structure Assist

Quinn Mcgehan Electrical Lead Internal Testing Programming

Assist

Alexandra Jung Budget//Plan Lead Structure Testing

Electrical Assist

Mark Sakaguchi Programming Lead

Science Testing Data

Analysis

Biggest Worries

• The Biggest Worries Of Team Solkraft Are…– Camera failure incl. camera fogging up– Hardware failure i.e. solar panels breaking– Sufficient Programming and debugging– Lack Of Sleep