James Bader, Jordan Dickard, Blake Firner, Amanda Kuker, Michael Lotto, Diana Shukis11-05-09

Mission Statement The BalloonSat Photon Phinder will be sent to an altitude

of approximately 30,000 meters to collect scientific data that will measure the intensity of light emitted from the sun at different altitudes in the atmosphere of the Earth and compare it to the current output of a modern photovoltaic cell.

Mission Objective The data collected will aid scientists in determining the

optimal altitude to maximize solar cells performance. This will aid in research for future renewable energy sources. A need for more productive solar energy is the basis for this experiment. The data collected will reveal if/where the optimal altitude is for maximum efficiency of solar cells by comparing solar cell efficiency against altitude and atmospheric conditions, along with the ambient light intensity. Determining the best altitude for solar cell efficiency will lead to future advancements in the renewable energy, paving the way to a practical solution.

Our satellite will be constructed of foam core and aluminum tape. Insulation will be used to ensure the power supply is not drained from cold temperatures. Two solar cells and a light intensity sensor will be located on the top of the structure. Both solar cells will be wired to an ACS 712 Current Convertor to convert the solar cell outputs to a readable voltage reading. The Light Intensity Sensor will draw 5 volts from the AVR board. Accompanying these primary experimental sensors, a temperature sensor, a pressure sensor, and a camera will be used to expand the knowledge of the ambient surroundings. Tying these all together is an AVR board that will record all information reported by each sensor.

An ACS 712 Current Convertor will be used to convert incoming current from the solar cells to an equivalent analog voltage reading. To calibrate this sensor, a 5 volt power supply was used to measure the referred voltage with no current. After this, current was added to create a measurable voltage drop across the sensor. The difference of these voltages divided by the current, gave a calibration of 7.66 Volts per Amp.

The monocrystalline solar cells are wired in parallel to increase the current output to the ACS 712 Current Convertor. It was determined that having a load that matches the internal resistance of each solar cell will maximize the current produced. To do this, An 82 Ohm resistor was added to each monocrystalline solar cell, which in turn optimizes each output.

The eight pins of the Light Intensity Sensor require a specific circuitry to maximize the resolution. Five of the pins require a 5 volt supply to both power and maximize the resolution of the sensor. Only one pin acts as a ground, and the seventh acts as an output pin to the board. The last pin is not needed with this experiment’s interface.

This graph shows the light intensity during the cold test. When the payload was turned on the satellite was exposed to light and therefore recorded a high light intensity. When placed in the cooler for the cold test the sensor was not exposed to light and therefore recorded a very minimal amount of light. This data reveals that our light sensor is working properly and will take accurate data for the length of the mission.

All other sensors functioned properly for the entire duration of the cold test. Since no other variable was changing other than the temperature the data for all other sensors was a constant value. The only other sensor that indicated a changing value was the light intensity sensor.

As the graph shows, the temperature first increased slightly due to heat created by the batteries then proceeds to steadily decline.

First the satellite was left still and therefore the beginning values of the graphs stayed unchanged.

Next the box was tilted on its end, affecting the y-high accelerometer.

Then, the satellite was left still again for a short period of time after which it was tilted on its side affecting the x-high accelerometer.

Next, the temperature sensor was tested by placing a finger on the sensor to increase the temperature reading.

The pressure sensor was unaffected during the test and therefore the graph shows a constant value.

Throughout the entire test, the light intensity sensor was affected. When the box was left still a high light intensity value was recorded. The first drop in light intensity resulted from tilting the satellite on its end and consequently out of the direct light. The second drop resulted from tilting the satellite on its side for the same reason. The third and even larger drop resulted from opening the lid of the satellite to test temperature. During this time the sensor was nearly completely out of the light. The final drop was the true test of the sensor in which it was covered and had no light at all to record.

From the tests, the team determined that all sensors are working properly and are flight ready. The system functions correctly as a whole and the team expects to retrieve good flight data to analyze.

The team expects that as the satellite ascends through the layers of the atmosphere the light intensity will be greater therefore making the solar cells more efficient. In addition, the team expects the solar cells to be more efficient above the ozone layer because the solar cells won’t be shielded by that protective layer of the atmosphere.

The team expects the satellite to drift while in flight and therefore be recovered somewhere in Eastern Colorado.

The team will test taking data on the ground prior to launch day. Recording experimental data and practicing the retrieval and analysis of it will help the team to be prepared for work with the actual flight data.

Our biggest concern at this moment is data retrieval

Mission Statement (Goal) The BalloonSat Photon Phinder will be sent to an altitude of

approximately 30,000 meters to collect scientific data that will measure the intensity of light emitted from the sun at different altitudes in the atmosphere of the Earth and compare it to the current output of a modern photovoltaic cell. The satellite will also measure the temperature (C), pressure, and the x/y axis acceleration at different altitudes.

Mission Objectives (from Goal)  O1: Constructed with the ability to operate at an altitude of

approximately 30,000 meters, the BalloonSat shall be built with a monetary budget of $100 and a mass budget of 850 grams, and be launched on November 7, 2009.

O2: The BalloonSat shall collect data to ensure the current output of monocrystalline solar cells is a function of altitude in the range of approximately 1,400 meters to 30,000 meters above sea level.

O3: The BalloonSat shall collect data to quantify the ambient light intensity as a function of altitude in the range of approximately 1,400 meters to 30,000 meters above sea level.

Objective Requirements: O1A: The BalloonSat shall be constructed by October 27, 2009 for a full

mission simulation while meeting our $100 budget for scientific equipment. O1B: The BalloonSat shall be a rectangular prism constructed of foam core,

hot glue, insulation, and aluminum tape as the main structure. This will contain all hardware the system will rely upon.

O1C: The BalloonSat shall be constructed at the University of Colorado at Boulder and launched in Windsor, Colorado.

O1D: The BalloonSat shall function for approximately 2.5 hours and reach an altitude of approximately 30,000 meters. The expected useful data shall be found in the 90 minutes of ascent, which will be compared to the control of 10 minutes before and after flight.

O2A: The timeline for data collection for the BalloonSat shall begin at t-minus 10 minutes before launch through t-plus 10 minutes after touchdown.

O2B: A pair of 2.54 cm x 4.445 cm monocrystalline solar cells shall represent solar cell efficiency by providing a current to be analyzed compared to altitude.

O2C: The pair of solar cells shall be located on the top of the satellite at opposite ends and shall be wired to a current sensor to convert the solar cell output to an analog signal compatible with the AVR microcontroller.

O2D: The pair of solar cells shall begin collecting data at t-minus 10 minutes, through 135 minutes in the air, and end after 10 minutes past touchdown.

O3A: The timeline for data collection for the BalloonSat shall begin at t-minus 10 minutes before launch through t-plus 10 minutes after touchdown.

O3B: The 1 cm x 1.2 cm light intensity sensor shall measure and convert light intensity into equivalent frequency.

O3C: The light intensity sensor shall be located on the top of the satellite and wired directly to the AVR Microcontroller.

O3D: The pair of solar cells shall begin collecting data at t-minus 10 minutes, through 135 minutes in the air, and end after 10 minutes past touchdown.

System Requirements (level 1) O1A

i: A detailed schedule with key milestone dates shall be created to ensure the deadline is met. ii: Furthermore, the full system shall be tested and simulated with a full mission test ensuring system integration.

O1B i: A detailed design and diagram of the BalloonSat structure with positioning of all hardware shall be created. ii: The acquisition of all necessary materials to build the structure shall enable the creation of the BalloonSat.

O1C: i: All hardware construction shall be done at the University of Colorado, using the equipment provided by the

university. ii: On November 7, 2009 the BalloonSat shall be launched from Windsor, Colorado during the early morning.

O1D: i: Brand new, fully charged batteries shall be used to power the systems within the BalloonSat. Two 9V batteries

will provide power to the AVR Microcontroller. Three 9V batteries shall provide power to the heater. Two AA batteries shall give power to the camera. The light intensity sensor shall draw power from the AVR Microcontroller.

ii: The AVR Microcontroller will be programmed to store date for the entire duration of the flight with an extra 10 minutes of data storage before and after the flight.

O2A: The AVR Microcontroller shall be programmed to take an analog reading from the solar cells once every 65 milliseconds.

O2B: Two 2.54 cm x 4.445 cm solar cells shall convert solar energy to equivalent current, which will then be converted by an ACS712 Breakout current to analog convertor to send a voltage output to be read and stored by the AVR Microcontroller.

O2C: To secure the solar cells to the top of the satellite on opposite sides, Velcro will be used and complemented with aluminum tape. The ACS712 Breakout sensor shall be secured adjacent to the AVR Microcontroller to minimize extensive wiring. The current sensor requires calibration for data analysis.

O2D: To ensure 2.5 hours of data retrieval, three 9V batteries shall be used to power the heater to maintain operational temperature while two 9V batteries shall be used to power the AVR Microcontroller. The solar cells shall require no power source to transmit a current.

O3A: The AVR board will be programmed to store an analog reading provided by the Light Intensity sensor once every 65 milliseconds.

O3B: One light intensity sensor shall convert light to an equivalent frequency. The sensor shall be wired directly to the AVR Board, which shall read and store the data provided by the sensor.

O3C: The light intensity sensor shall be embedded and hot glued into the foam core between the two solar cells and adjacent to the flight tube.

O3D: To ensure 2.5 hours of data retrieval, three 9V batteries shall be used to power the heater to maintain operational temperature while two 9V batteries shall be used to power the AVR Microcontroller. The light intensity sensor shall draw power from the AVR Microcontroller 5V output slot.