spacegrant.colorado.edu · Web viewThe mission is going to be completed by building a 17x17x17 cm cube made out of foam core. It will be held together with hot glue and aluminum tape

Colorado Space Grant Consortium

GATEWAY TO SPACEFALL 2012

DESIGN DOCUMENT

Team Spirit of the Koala

Project VOLT

Written by: Thomas Jeffries, Anthony Anglin, Starteya Pais, Colin Harkins, Dustin Fishelman,

Joao Mansur, Andrew Trujillo, Dylan Cooper

12/13/12

Revision D

Gateway to Space ASEN 1400/ASTR 2500___________________________________Fall 2012

Revision Log

Revision Description DateA/B Conceptual and Preliminary Design Review 10/18/12C Critical Design Review 11/15/12D Analysis and Final Report 12/13/12

Acronyms

Acronym MeaningTSOK Team Spirit of the Koala

Team SOK Team Spirit of the KoalaBalloonSat Balloon SatelliteMissionSim Mission Simulation

Page 2 of 30Team Spirit of the Koala December 13, 2012Project VOLT Rev D


Table of Contents

1.00 Mission Overview…………………………………………………………………….……..42.00 Requirements Flow Down……………………………………………………………….…..63.00 Design………………………………………………………………………………….…….74.00 Management………………………………………………………………………………...135.00 Budget………………………………………………………………………………………146.00 Test Plans and Results……………………………………………………………………...167.00 Expected Results……………………………………………………………………………248.00 Launch and Recovery………………………………………………………………………249.00 Results and Analysis………………………………………………………………………..2410.00 Ready for Flight…………………………………………………………………………...2811.00 Conclusion and Lessons Learned……………………..…………….………….……….…2912.00 Message to Next semester…………………………………………………………………2913.00 References…………………………………………………………………………………30



1.00 Mission Overview

1.01 Mission Statement

Determine the feasibility of using the flow of atmosphere across the surface of the BalloonSat, flown to 30 kilometers, during accent, to provide power to a BalloonSat.

1.02 Primary Experiment

Team Spirit of the Koala will attempt to generate current using the rotation of the BalloonSat during the accent through the atmosphere. The BalloonSat will attach to the flight tube with ceramic stainless steel bearings. This will allow the BalloonSat to rotate independently of the flight tube during the accent. A magnet attached to the flight tube will spin within coils of copper wire. TSOK hopes to use this rotation to generate current.

This is a graphic taken from an online simulator, demonstrating the concept behind our experiment. The water pouring from the faucet on the left spins the magnet. This creates a changing magnetic field, field lines shown by the red and white arrows, which induces an electromotive force in the wire coil. This electromotive force produces a voltage across the resistor in accordance with Faradays’ law. This voltage creates a current in accordance with ohms law.

http://phet.colorado.edu/en/simulation/generator


http://phet.colorado.edu/en/simulation/generator


1.03 Experiment Background

The spinning of the magnet in the BalloonSat will create a change in flux, inducing a electromotive force in the copper wire, in accordance with Faraday’s Laws of electromagnetic induction. Faraday’s Laws state that the voltage produced, across a resistor, in a coil of wire is proportional to the negative rate of change of magnetic flux. The greater the angular velocity of the magnet, the higher the change in flux will be. This means that the faster the magnet spins, the higher that current generated will be.

1.04 Expected Discovery

We expect to discover that the current generated will be inconsistent. This will show that wind power is unfeasible for use as a primary power source on BalloonSat missions. We expect this result due to differences in turbulence at different altitudes. Another reason we expect this result is due to decreasing density of the atmosphere during accent. TSOK will use fins, composed of foam core attached to the exterior of the BalloonSat, to dampen fluctuations and provide a more consistent, improved spin rate.

1.05 Experiment Origins

The reason for conducting this mission is to determine the feasibility of using wind to power experiments in future BalloonSats. Weight could be saved on BalloonSat missions, by reducing the number of batteries necessary to power the BalloonSat, if power can be generated using wind.

1.06 Special Features

TSOK’s BallonSat will include a GO PRO video camera. This footage will assist in displaying our experiment at the design expo, demonstrating what the flight experience was like. This can also be used to inspire outside interest in BalloonSats, engineering, and space exploration.

2.00 Requirements Flow Down

This Requirements flow down chart will guide us in project development. It is used to keep our project on track and for us to verify each requirement as traceable, necessary, verifiable, attainable, and clear. Our level zero requirements are derived from the RFP requirements and



our mission statement. These primary systems are labeled A-E with their corresponding sub-systems.

Number Requirement OriginLevel 0 Requirements

Experiment

0.1 Project Volt shall collect data on current and voltage created by an electric generator as the BalloonSat spins.

Mission Statement

0.2 The BalloonSat will rotate independently of the flight string. Mission Statement

Structure

0.3 The BalloonSat will withstand the environment at up to 30,000m and the forces of balloon burst.

Mission Statement

Data

0.4 The BalloonSat will take data about the environment to give meaningful comparison for data obtained from the electric generator.

Mission Statement

Level 1 RequirementsExperiment

1.1 A functional electric generator will be constructed and integrated into the attachment point of the flight string to the BalloonSat.

0.1

1.2 An Arduino will be programmed to sample and record the current and voltage off of this generator using an Attopilot combined current and voltage breakout.

0.1

1.3 The flight string attachment point will be mounted to the body of the BalloonSat via a set of ceramic bearings.

0.2

Structure

1.4 All instruments flying in the BalloonSat will be contained within a hard, heated and insulated structure made from both foam core and insulating foam.

0.3

1.5 All items inside the BalloonSat will be tightly secured to the sides using Velcro to avoid damage in the post balloon pop environment.

0.3



Data

1.6 The BallonSat have a GoPro Hero 2 and a Canon A780 onboard to record the flight.

0.4

1.7 The BalloonSat will be launched with an accelerometer, a pressure sensor, internal and external temperature sensors and a humidity sensor

0.4

1.8 An Arduino will be programmed to record all environmental data coming from the different sensors

0.4

3.00 Design Overview

3.01 Design Plan

Project Volt’s structure will accommodate for all necessary systems. Team SOK will build a prototype BalloonSat that will be used for all ground testing. At this moment all materials have been purchased or received. If we need more structural materials they are available at the Gateway Store. Team SOK will adhere to the schedule and complete all tasks to ensure a successful flight. During the testing process if we find that a redesign is necessary we will address it quickly and effectively. Since the primary objectives of generating rotational velocity relies upon our fin design, we will perform multiple tests and try different designs to ensure this system works on the ground before flight. We understand that this has been a primary objective of previous flights and they have failed. By thoroughly testing this system we will ensure completion of this objective. Following recovery of our BalloonSat, we will collect and analyze all data recorded from the flight.

3.02 Structure

The mission is going to be completed by building a 17x17x17 cm cube made out of foam core. It will be held together with hot glue and aluminum tape. Fins will be glued to the outside of the structure, one four for each side of the cube. The design of the fins has not been determined yet, because that is part of our testing experiment, to see which design will create the most spin. The inside of the cube will be lined with one or two layers of thermal insulation to ensure the BalloonSat is kept warm during flight. Through the top and bottom will be a hole, each filled with a ceramic stainless steel bearing. The flight tube will go through the middle of the BalloonSat and be held in place by a string tied in a knot.

3.03 Imaging



TSOK will image the environment during flight using both a Canon camera and a GO PRO. The Canon and the GO PRO will be attached to the walls of the BalloonSat, pointing outward. Holes will be cut in the exterior of the BalloonSat, over the lenses of the Canon and GO PRO, allowing the Canon and GO PRO to record images of the environment.

3.04 Generating Current

Inside the BalloonSat, a magnet will be glued, oriented perpendicularly, to the flight tube. On one side of the flight tube, wire will be coiled, about an axis parallel to the magnet. This coil will be placed as close to the magnet as possible, while still allowing the magnet to spin freely without contact. The ends of the coil will be attached to a current sensor, completing the generator circuit. As the magnet spins, the changing magnetic fields will induce a voltage across a resistor, causing a current in the wire. This current will be measured using a current sensor attached to an Arduino.

3.05 Arduinos and Other Sensors

The combined current/voltage sensor will be attached to an Arduino unit with a shield and micro SD card in order to record the data from the experiment. The Arduino will be powered by 9V batteries. A heater will be attached with a switch inside the cube. The heater will also be powered by 9V batteries. Next to the heater will be another Arduino unit with a shield and micro SD card. This Arduino will have a relative humidity sensor, an internal temperature sensor, a pressure sensor, and an external temperature sensor connected to it. The external temperature sensor will be placed on the exterior of the BalloonSat.

3.06 Parts/Hardware Needed

Canon Camera (Space Grant) GO PRO (Purchased by team member) Neodymium Magnets (apexmagnets.com) Voltage/Current Sensor (sparkfun.com) Copper Wire (Home Depot) Arduinos (Space Grant) Arduino Shields (Space Grant) SD cards (Space Grant) Environmental Sensors (Space Grant)

3.07 Parts Ordered and Received



Ordered Parts: Neodymium Magnets Sealed Ceramic Stainless Steel Ball Bearings Current/Voltage Sensor

Order Status: Magnets: Received Bearings: Received Current Sensor: Received Copper Wire: Purchased GO PRO: Purchased

3.08 3D and 2D Pictures


17 cm

17 cm

Magnet

Wire Coil

Go Pro

Arduino w/ internal temperature, pressure, humidity, and accelerometer

Flight Tube

Heater

Canon Camera

Aruino w/ external temperature, internal temperature, and current.



17 cm

17 cm

Arduino w/ internal temperature, pressure, humidity, and accelerometer

Go Pro

Wire Coil

Magnet

Flight Tube

Canon Camera

Aruino, w/ external temperature, internal temperature, and current.



Arduino w/ Voltage and External Temp Sensors

17 cm

17 cm

Heater

Canon Camera

Coil of Wire

GO Pro

Magnet

s

Batteries

Arduino w/ Internal Temp, Pressure, Humidity, Acceleration Sensors


3.09 Functional Block Diagram

4.00 Management and Scheduling

4.01 Management


GoPro Hero 2Canon A780

Heater

Environmental Sensing Arduino

Voltage Sensing Arduino


4.02 Scheduling

*Team Meetings every Sunday and Monday and as necessary*September 28th………………………………………………………... Turn in proposal (4:00 pm)October 2nd….………………………………………………...CoDR Presentations Due (7:00 am)October 4th………………………………………………………………….Order all the hardwareOctober 5th………………Authority to Proceed by appointment with Chris (9:00 am - 3:00 pm)October 7th………………………………………………………..Finalize design + Team meetingOctober 13th…………………………………………….......................Have acquired all hardwareOctober 14th…………………………………………………………………….Begin constructionOctober 18th………………Design Document Rev A/B (7:00 am) + pCDR Slides Due (7:00 am)October 21st…………………………………….Testing: Structural Test: Drop Test and Roll TestNovember 4th………………………………………………………………..Finalize programmingNovember 13th..........................................................Testing: Structural Test: Whip Test and Cooler Test + Sensor Test: Imaging Tests


Thomas JeffresLeader, Budget

Manager, Structural Design, Backup

ProgrammerAnthony Anglin

Coordinator, Researcher

Starteya PaisStructures, Researcher

Colin HarkinsStructures, Secretary

Dustin FishelmanCoordinator,

Structures, Secretary

Joao MansurResearcher, Structures

Andrew TrujilloResearcher, Backup

Structures

Dylan CooperLead Programmer


November 14th…………………………………Testing: Overall Test: Experimental Systems TestNovember 15th……………………………………..Design Document Rev C (7:00 am) + In-

Class Demo (Mission Simulation Test)November 25th………………………………………………Finalize satellite and prep for launchNovember 27th………………………………………………………….LRR Slides Due (7:00 am)November 30th……………………………………………………………………...Final Weigh-inDecember 1st ……………………………………...Launch day @ 6:50 AM (Weather Permitting)December 2nd…………………………………………………………………….Celebration PartyDecember 3rd……………………………………………………………….System Failure TestingDecember 4th……………………………………Launch Recap/Report + Data Analysis GuidanceDecember 8th………………………………………….ITLL Design Expo + Design Document

Rev D Due (7:00 am) + Extra Credit Video DueDecember 11th………………………………………………………..Final Presentations and Reports (7:00 am) + BalloonSat hardware turn-inDecember 12th (Final Class) ……………………...Final Team Evaluations + Homework #09 Due

*Schedule after December 1st if launch postponed will be pushed back according to the postponed launch date*

5.00 Budget

5.01 Weight

Hardware Weight (g) Quantity SubtotalBearings 9.07185 2 18.1437

Magnets 132.297 1 132.297

Voltage Sensor 1 1 1

Arduino 30 2 60

Arduino Shield 30 2 60

Copper Wire 34.8 1 34.8

Accelerometer 1 1 1

Pressure Sensor 1 1 1

Temperature Sensor 1 2 2

GoPro 200 1 200

Camera 130 1 130



Humidity Sensor 1 1 1

Batteries 40 6 240

Heater 300 1 15

Structure 415 1 415

Total N/A N/A 1211

We are currently 86 grams overweight. TSOK traded with team 2 for an additional 80 grams of weight, and was given an extra six grams by Professor Koehler.

5.02 Budgeted Expenses

Hardware Cost Quantity S/H SubtotalBearings 14.95 2 6.11 36.01

Magnets 19.99 2 6.65 46.63

Voltage Sensor 19.95 1 0 19.95

Velcro 22.23 1 0 22.23

Total N/A N/A N/A 124.82

5.03 Additional Expenses

Hardware Usage Cost Quantity SubtotalDry Ice Cooler Test 1 26 1 26

Dry ice Cooler Test 2 12 1 12

Total N/A N/A N/A 28

5.04 Provided Items

Item Quantity UsageArduino 2 Data Collection

Arduino Shield 2 Data Collection

Accelerometer 1 Measuring Acceleration

Pressure Sensor 1 Measuring Pressure

Temperature Sensor 2 Measuring Temperature

Camera 1 Environment ImagingPage 15 of 30

Team Spirit of the Koala December 13, 2012Project VOLT Rev D


Batteries 5 Power

Heater 1 Maintain Temperature

Switches 3 Control Electronics

LEDs 4 Indicators

Foam Core N/A Structure

Insulation N/A Maintain Temperature

Hot Glue N/A Structure

Flight Tube 1 Attach to flight String

Washer 2 Structure

Aluminum Tape N/A Structure

Wires N/A Electronic Connections

Solder N/A Electronic Connections

6.00 Testing

To test the integrity of the satellite, we will have a variety of different simulations and tests under different conditions. These include drop tests, cooler tests, whip tests, imaging tests, mission simulation tests, experimental system tests, and tests looking at the effectiveness of different fin types and sizes.

6.01 Drop Test

A prototype version of the structure of our BalloonSat will be constructed with the same dimensions and weight. This prototype will include the insulation and to simulate mass will include rocks that are taped into place (to prevent damage because of the rocks moving around). These rocks will need to weigh a total of approximately 980 grams to properly simulate the mass of the components that will be housed inside the BalloonSat. Once this is completed a variety of different drop tests will be conducted from different heights available to us. All heights should be in excess of 10m and with additional force pushing the prototype toward the ground. This will simulate a worse-case scenario landing. If the BalloonSat structure survives this, we can be sure that it will survive the landing and the balloon pop on launch day.Results:

The prototype box was dropped from a height of approximately 13m with mass simulators weighing a total of approximately 2kg. This weight of more than our allowed mass is to ensure that the box will hold up to a large amount of kinetic energy being transferred from it as it impacts the ground. The mass simulators were secured inside the box with duct tape. In the end, the box survived very well (enough to repeat the test two more times with the same results)



aside from a few dents along the edges. There were no breaks in the box and all of the rocks were still secured when the box was opened again.

6.02 Cooler Test

With the same prototype as mentioned above a cooler test using dry ice will be conducted. During this test the dry ice will bring the BalloonSat down to temperatures similar to those at the coldest point during its fight. Inside the prototype there will be a single Arduino Uno with internal and external temperature sensors wired up to it and the heater, constructed out of ceramic resistors and 3 9 volt batteries. In addition to these systems all of the camera systems will be functioning and recording. These systems will provide data on how close to flight temperatures we achieved with the dry ice, as well as how well the insulation kept the temperature up in the BalloonSat. This data will also give information on how all of the components inside the BalloonSat function at low temperatures. Through this we can determine what systems will need to be closest to the heating system. To succeed in this aspect of the mission we need to keep the internal temperature above -10 degrees Celsius.

Results:


BalloonSat


0.04 3.43 6.82 10.22 13.61 17.00 20.41 23.80 27.20 30.60 33.99 37.39 40.780

10

20

30

40

50

60

Cooler Test Data

Pressure (psi) AccelX (g) AccelY (g) AccelZ (g) Humidity (%) Internal Temp (Deg C)

Time (min)

Placed in Cooler Removed from Cooler



0.05 3.77 7.49 11.2114.9418.6622.3826.1029.8233.5537.2740.9944.7248.440

5

10

15

20

25

30

35

Cooler Test Data

Voltage (V) Current (I) Internal Temp (C) External Temp (C)

Time (min)

Placed in Cooler

Removed from Cooler

The cooler test was a success because the internal temperature stayed above 10 degrees Celsius for the duration of the test.

6.03 Whip Test

To ensure the integrity of the flight string attachment point, we will need to conduct extensive whip tests simulating the forces that will be experienced after balloon pop. These tests will need to be so extensive because our entire experiment depends on this point. With a prototype box we will construct a working mock-up of the flight tube and the bearings that let it rotate independently of the BalloonSat. Mass simulators will be put in place of all hardware. From this point we will connect the flight tube to a section of string in the same manner that it will be connected on launch day. The BalloonSat will be violently whipped around in an effort to simulate the extreme forces present when the balloon pops. Whether or not the fight tube and the rest of the structure attaching the bearings hold up will tell us whether or not we need to rethink the attachment points.

Results:



The test was successful. The BalloonSat sustained no damage. The flight tube attachment remained secure throughout the test. All interior components remained in place.

6.04 Imaging Tests

Imaging tests will be conducted inside of one of our prototype boxes. This will ensure the placement and that the software that controls the Canon A780 camera. In addition to this, the imaging test will show us how long the batteries will last on both the Canon Camera and the GoPro.

Results:

Both cameras were mounted into the BalloonSat and turned on to test their field of view as well as their battery life. The field of view on each of the two cameras included the fins on the sides of the box to watch for any failure during the flight. Both of the cameras were mounted inside and turned on to the mode they will be running in during the flight and both tested to have a battery life around the range of 2.5 hours. We know that temperature often has a very large effect on battery usage in electronics. To negate some of this effect we will be locating the heater next to the batteries for both Arduinos and the Canon A780 camera. The Go Pro Hero 2 has a built in heater to preserve its battery life in very cold temperatures.



6.05 Experimental Systems Test

The Experimental Systems test will be the test of the experimental structure. The flight tube will be mounted on the bearings with the magnets attached to the flight string. The system of coils will be constructed and there will be an Arduino located inside the BalloonSat prototype. The BalloonSat will be spun around the flight tube. The current and voltage produced by the generator will be written onto a 2GB SD card and stored. This test will ensure that all of our coding for the experimental sensor works properly and that the system actually functions to generate current. The data received from this test will give us background on how our experimental system sensor is working and if we need to adjust some of its components such as the VREF and gain.

Results:The Experimental Systems Test went well. Upon looking at the results we immediately saw that it would be necessary for us to adjust the gain on the sensor due to the overwhelming noise and the fact that the sensor could not process the range it needed to sample on with such sensitivity. This first test is illustrated by the first graph. To solve these issues we turned the gain down on the sensor. This is illustrated by the second graph.



min 1.00 1.98 2.97 3.96 4.95 5.94 6.93 7.92 8.91 9.90 10.8911.8812.8713.860

200

400

600

800

1000

1200

Current (I)

Current (I)

Time (min)

millis (ms)6847 13641 20430 27211 34008 40799 47593 54374 61170 67962 747570

50

100

150

200

250

300

350

400

450

500

Current (I)

Current (I)

6.06 Mission Simulation Test

To simulate the entire mission we will have all of the components that will be present on launch located inside the BalloonSat. This includes all cameras, the Arduinos, and the entire experimental system. The BalloonSat will be spun so that a voltage can be measured. This test will ensure that all components running in the mission work properly while running at the same



time and that they will perform for the extended periods of time that they will be required for during flight.Results:

The mission simulation test ran for approximately 2 hours and 40 minutes. All systems performed well, indicating that the BalloonSat is ready for launch.

0.26 23.36 46.48 69.60 92.72 115.84138.97162.08185.22208.33231.44-10

0

10

20

30

40

50

60

70

Environmental Sensors

Pressure (psi) AccelX (g) AccelY (g) AccelZ (g) Humidity (%) Internal Temp (C)

Time (min)

min 1.06 2.11 3.16 4.21 5.26 6.31 7.36 8.42 9.47 10.5211.5712.6213.670

10

20

30

40

50

60

70

Temperature

Internal Temp (C) External Temp (C)

Time (min)

6.07 Safety



SOK will use many techniques to ensure both the safety of ourselves, as well as the safety of any onlookers during our tests. During flight the BalloonSat will be securely fastened to the string of the balloon, preventing the BalloonSat from falling separately from the balloon apparatus. During all drop tests team members will station themselves about the drop area to prevent any persons or items from entering the landing area. Whip tests will only be conducted in open spaces with all nearby persons warned of the possibility of whip test failures and pieces or all of the BalloonSat launching through the air. During cooler tests we will ensure that the cooler is not sealed, allowing a pressure release so that CO2 will not buildup and violently rupture the container. Additionally, SOK will place an American flag sticker onto the outside of the BalloonSat. University of Colorado Boulder’s contact information will also be written on the side of the BalloonSat. These two measures will help if the BalloonSat is recovered by a non-SOK team member. Basic common sense will also be used to maintain safety of all involved.

7.00 Expected Results

We hope to recover data from our flight confirming our hypothesis that wind power is not a feasible primary source of power for BalloonSats. We expect that the amount of power generated will be greatest in the first part of the flight. It will increase to its highest near the top of the troposphere, where average wind speeds are highest. From this point it will start to go down because the air is much less dense in the high atmosphere. The lower density of the air should make for less force spinning the balloon. This would mean that to apply this power toward the entire flight, it would need to be stored throughout in some type of system. All of this data will come in the form of discrete data points of current and voltage. By putting all of this data through a function to multiply the two, the instantaneous power going through the circuit. This data will be graphed and compared to the altitude of the BalloonSat (calculated from the atmospheric pressure samples obtained during flight.

8.00 Launch and Recovery

On December 1st, 2012 our BalloonSat will launch. TSOK member Dustin Fishelman will be the team member holding the BalloonSat as it launches. The entire TSOK will be traveling to recover the BalloonSat which will be located through the GPS sensor that is launched with the BallonSat. This GPS data will be relayed to us by Professor Koehler. To recover all of the flight data, we will remove the 2 GB SD cards from each of the Arduinos and the Canon Camera and the 32 GB SD card from the Go Pro Hero 2. At this point, the data will be put on a computer and backed up to another drive before being analyzed and graphed in Microsoft Excel. We have done this same procedure when preforming cooler testing to verify that it actually works.

Launch occurred at approximately 7:30 AM on December 2nd, 2012. The launch proceeded without issue. The chase led us to corn field near Venango, Nebraska. The BalloonSat was recovered just before 1:00 PM.



9.00 Results, Analysis, and Conclusion

9.01 Results and Analysis

Upon the recovery and analysis of our flight data it quickly became apparent that something had gone wrong at some point in flight. Both Arduinos seemed to have begun a cycle of resetting throughout the flight and there was little data to be recovered from either of the Micro SD cards that the Arduinos wrote to. Due to this fact we were forced to extrapolate many of our conclusions from the flight video and data obtained on the ground.

In analyzing the data we obtained from the Arduino measuring the current across the generator we saw that there is only approximately 2.5 minutes of data. All data recovered was prior to launch

min 0.17 0.34 0.50 0.67 0.83 1.00 1.16 1.32 1.49 1.65 1.82 1.98 2.15 2.31 2.48

-60-50-40-30-20-10

010203040

Temperature

Internal Temp (C) External Temp (C)

Time (min)

Looking at a graph of the current measured here we can see that the orientation of the magnet goes largely unchanged. This section of data may have been from an unknown point in the flight or when the BalloonSat was still on the ground before launch.



min 0.15 0.30 0.44 0.58 0.73 0.87 1.02 1.16 1.30 1.45 1.59 1.74 1.88 2.02 2.17 2.31 2.46 2.600

100200300400500600700800

Current (I)

Current (I)

Time (min)

Satellite spun prior to launch

The environmental sensing Arduino did slightly better but only gave a section of data covering about 38 minutes. All of this data was typical. Barometric pressure went down, internal and external temperature went down to expected levels, humidity had a spike (as it went through the clouds) and then went down after and the accelerometer relatively normal readings.

0.03 2.81 5.58 8.35 11.1213.8916.6719.4422.2124.9827.7630.5333.3036.0705

1015202530354045

Environmental Sensors

Pressure (psi) Humidity (%) Internal Temp (C)

Time (min)

Launch

Because of the constant readings from the accelerometer we could ascertain that burst did

not happen at any point during the time where this Arduino read. We compared our sensor data to a number of other teams so we could have an idea of where this section of data was from. It matched up well with the data other teams had received during the first parts of flight where the BalloonSat had taken off and then gone through the cloud layer.



0.03 2.57 5.11 7.66 10.20 12.74 15.28 17.82 20.36 22.90 25.45 27.9930.53 33.07 35.61

-4-3-2-10123456

Acceleration

AccelX (g) AccelY (g) AccelZ (g)

Time (min)

Launch

From watching our flight video we could determine that the BalloonSat had a very high angular velocity just after takeoff. If our experimental sensor had been running at this point in time it should have seen a high number of fluctuations per minute in the current produced by the generator. After the BalloonSat reached the cloud layer we saw that it almost entirely stopped spinning. Aside from some slow rotation, this continued for the entire duration of the flight. The time that the BalloonSat actually spun and would have created power was only a fraction of the time it was in flight.

We can conclude from the data present that a system such as ours where the flow of the atmosphere across the surface of the BalloonSat is used to create power would not be feasible. We determined this by looking at the inconsistent spin of the BalloonSat and some of the characteristics of the system we employed. First, it only spun at the rate we intended it to for the first part of the flight. The amount of power generated from this would likely not be enough to power any significant systems onboard the BalloonSat and would undoubtedly not outweigh the advantages of using batteries. Second, the experimental system used a very great amount of the weight that we could fly. If we were to devote all of this weight to other sources of power such as batteries, we could power the BalloonSat for a great deal longer as well as provide a much more reliable power system. In the end, we can say that it is possible to provide some power from a system such as ours; it is not possible for this system to, by itself, power a BalloonSat, without being augmented with an additional power supply system.

9.02 Failure Analysis

Although we saw in our flight video that the BalloonSat did spin a great deal during the first part of its flight, there was little data to give us any context to what had happened with the generator during that period of time. The data we did recover from the Arduino with the experimental system consisted of only 3 minutes or so of actual sampling. After that point there are a large number of empty data files that fill up the space where the data from the rest of the flight should have been. This same thing happened with the other Arduino in the BalloonSat that



was measuring environmental variables, only it managed to run for a longer time before succumbing to the same fate.

The way both of the Arduino systems had failed tells us a great deal about what may have happened in the flight. We saw on both Micro SD cards that after the first set of data there were only a number of empty files. This indicates that the Arduinos did not fail entirely, but in fact they had kept turning on and off during the flight. Each time they had reset, it would create a new data file to be filled. They stopped reading data but were still functional and trying to run the code that was uploaded onto them to read the sensors and record the data to the Micro SD card each had onboard.

This lack of real data about the flight left a large gap in what we could determine happened to ultimately cause the experiment to fail. We had tested it numerous times with the exact same components that had been flown on launch day (aside from the batteries). A two hour and 40 minute MissionSim had been performed the day before flight. The only system that had changed prior to flight had been the set of batteries installed for launch day. Upon realizing this we performed extensive testing on the batteries used in flight, only to find that the same issue came up. Both Arduinos would reset periodically and then entirely stop reading data even though both batteries had enough power to support the Arduino systems. When the Arduinos were set up to be powered by a computer they had no issues and sampled from each sensor as intended. This pointed to an issue not with the Arduino system but with the mobile power supply that it had used during flight. When each Arduino was powered by a new 9 volt battery this problem entirely disappeared. Everything ran as intended without any of the resetting problems that had appeared in flight. We received similar data as during our preflight testing.

Beyond this issue, when we opened the box after recovery we found that the set of three batteries powering the heater had become dislodged from where they were bound to and had stuck to the magnet. This most likely happened in the moments after burst (or cut in our case) when the BalloonSat is subject to a great deal of force. While if this had happened at burst, it would not have affected our experimental data, it is an issue for re-flight. If a failure like this were to happen with an Arduino (which was secured in the same way as the batteries) it could ruin our chances of being able to fly again. To fix this issue, we have moved the batteries farther away from the magnets in the box and we have secured each of the components inside the BalloonSat better.

10.0 Ready for Flight

Our payload is currently entirely ready to fly again. After recovery, there were only some minor changes to be made so that it could be flown again. First, we placed all of the batteries farther away from the magnets and we secured them better. We ran into a problem sometime during flight when the batteries used for the heater became separated from where they were attached and stuck to the magnet. This stopped the entire BalloonSat from rotating as it should have around the flight string. Keeping these components separated from one another better will prevent a failure similar to this in future flights. All of the components of our structure were completely intact and will not need to be replaced or adjusted. Our payload should be stored so that it is not in a cramped space. If any of fins on the outside of the box are damaged they will need to be replaced before another flight so that they can properly catch the flow of the



atmosphere across them. Aside from this, our BalloonSat does not have to be stored in any particular orientation. The payload can be activated simply by turning on all of the switches located on the exterior of the box. Each switch has an LED accompanying it to indicate the status of the system it is controlling.

11.00 Conclusions and Lessons Learned

Team Spirit of the Koala learned many lessons through the semester. We learned a lot about each other, a lot about patience, and a lot about BalloonSats. We learned how to build a generator. One of the greatest challenges we faced was construction of the electrical components of the satellite. All the wiring was custom made and soldered by hand. Additionally both Arduinos needed to be programmed to record all sensor data; this required us to learn the Arduino coding language. As a team we learned a lot about how long integration can actually take.

If we had a chance to do this project again, the main thing we would do differently is scheduling. We would use the syllabus to schedule important due dates. Moreover, we would set ourselves definite deadlines along the way. Allowing ourselves more time to integrate the satellite would have saved us a few longs nights and many headaches. Finally, a second thing that we would do differently is using glue to adhere the Velcro strips to the walls of the box. This would provide extra security and possibly eliminate our main failure.

12.00 Message to Next Semester

Professor Koehler was in fact correct in saying that we will spend more time on this class than any other class during the semester. You may not believe it at the beginning of the semester but this class will challenge you, stress you, keep you up until the early hours of the morning and most of all, things will go wrong at the worst possible moment. All of that said, Gateway to Space will be the most fun you have ever had on a project. It is immensely rewarding to launch what you have worked so hard on for so long. There are a number of things that as a team you can do to make the overall experience less stressful though.

To start, you must have a strong team leader, someone who will not be afraid to kick people into line to get done what needs to be done. This is because without a doubt there will be people on the team who do not want to contribute to the best of their ability. Second, do your research. You may have a good concept at the beginning and it may go well throughout the project, but you must know everything about how your concept works. In the case that you don’t, things will start to pile up very quick when you can’t understand something that has gone wrong. Third, work out just when your team can meet and have very good communication between team members. This will make everything else much less stressful. Overall, the main thing that we should have done differently was testing. Had we completed our MissionSim testing earlier we could have worked out all of our problems without needing to spend the night in SpaceGrant hours before the BalloonSat was due. In the end, have fun with the experience.



13.00 References

1.) "Faraday's Laws and Magnetic Induction." MIT Physics Notes. MIT, n.d. Web. <http://ocw.mit.edu/courses/physics/8-02sc-physics-ii-electricity-and-magnetism-fall-2010/faradays-law/MIT8_02SC_notes21.pdf>.

2.)"Faraday's Laws." Hyper-Physics. N.p., n.d. Web. 21 Oct. 2012. <http://hyperphysics.phy-astr.gsu.edu/hbase/electric/farlaw.html>.


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spacegrant.colorado.edu · Web viewThe mission is going to be completed by building a 17x17x17 cm cube made out of foam core. It will be held together with hot glue and aluminum tape