Team Hang 7-Project Aether
Colorado Space Grant Consortium
GATEWAY TO SPACE
FALL 2012
DESIGN DOCUMENT
Team Hang Seven
Written by:
Abby Caballero, Nikhil Desai, Chase Goodman, Ethan Hollenbach, Becca Lidvall, Lucas Migliorini, Paul Smith, Sierra Williams
12/12/2012
Revision D
Revision Log
Revision / Description / DateA/B / Conceptual and Preliminary Design Review / 10/20/2012
C / Design Document C: Final Design Review / 11/16/2012
D / Design Document D: Final Design Profile / 12/12/2012
Table of Contents
1.0 Mission Overview ...... 4
1.1 Mission Statement...... 4
1.2 Mission Background...... 4
1.3 Mission Summary...... 4
2.0 Requirements Flow Down ...... 5
3.0 Design ...... 6
3.1 Design Diagrams...... 8
3.2 Functional Block Diagram...... 9
3.3 Schematic...... 10
4.0 Management ...... 10
4.1 Team Positions...... 11
4.2 Schedule...... 11
5.0 Budget ...... 13
6.0 Test Plan and Results ...... 14
6.1 Testing Schedule...... 14
6.2 Structure Tests...... 14
6.3 Hardware Tests...... 16
7.0 Expected Results ...... 19
7.1 Graphs...... 20
8.0 Launch and Recovery...... 22
8.1 Pre-Launch Plan...... 22
8.2 Post-Launch...... 23
9.0 Results, Analysis, and Conclusions...... 23
9.1 Failures and Analysis...... 25
10.0 Ready for Flight...... 26
11.0 Conclusions and Lessons Learned...... 26
11.1 Conclusion...... 26
11.2 Lessons Learned...... 27
12.0 Message to Next semester...... 27
13.0 Special Thanks...... 28
14.0 References...... 28
1.0 Mission Overview
1.1 Mission Statement
The mission for team ‘Hang Seven’ is to design, build, test, and launch a BalloonSat to 30 kilometers. The BalloonSat “Aether” will be outfitted with one working homemade Geiger counter and one off-the-shelf Geiger counter. The objective for this mission is to discover how well we can manufacture a Geiger counter and measure how gamma radiation increases in relation to altitude.
1.2 Mission Background
In any manned mission, within the atmosphere or in space, human safety is of utmost importance. Safety has always been a priority in aviation. The Federal Aviation Administration has implemented many regulations to preserve and ensure human safety while in flight. Regulations have been passed regarding communications, structure, and passenger restraints. Subsequently, radiation is a main concern due to the prolonged effects of exposure on the human body during aircraft transit. Considering such risks, materials would have to be employed to ensure the safety of any passengers. Consequently, as altitude increases so does exposure to radiation of all kinds (alpha, beta, gamma); on a typical passenger aircraft traveling approximately 12,000 meters, the amount of radiation exposure will be double that on the ground. As one increases in altitude, much of the Earth’s natural protective attributes such as cloud cover, atmosphere, and the ozone layer are dissipated. Radiation in itself can be a lethal force, only 35 rad (.35 gray) of absorption will cause serious health effects. Negative health effects include: nausea, vomiting, hair loss, loss of consciousness, cancer, and even death. Such negative health effects could be affecting millions of people who travel in aircraft. Even minimal exposure to radiation may result in damage to the human body.
To give a general idea of how much radiation we are supposed to be measuring, a typical amount of radiation that an average person would receive a year would be around 1mSv/yr (0.1µSv/h average).
1.3 Mission Summary
Our original mission was to measure the depletion effect that two materials, carbon fiber and aluminum, have on blocking radiation levels. This proved to be problematic as we experienced many setbacks and problems while making our Geiger counters. To better fit our skills we created an alternative mission: we have chosen to develop one Geiger counter to measure the levels of Gamma radiation in the atmosphere. This is a change from making three and also removes the materials carbon fiber and aluminum from testing. Furthermore we will launch a kit Geiger counter from space grant alongside ours to record the actual radiation measurements. We will also modify the original designs we found online to better suit our requirements, specifically so it will record to an SD card rather than producing clicks. The data retrieved from these two devices will be compared to determine how efficient our Geiger counter measures radiation.
2.0 Requirements Flow Down
The requirements for the Aether mission are presented below. The requirements are an overview of what needs to be accomplished by our satellite. The level zero requirements are all derived from the mission statement. All subsequent requirements are either derived from the mission statement or the previous requirements.
Level / Number / Requirements / Requirement Met? / Derived From0 / 1 / Payload shall ascend to an altitude of 30 kilometers via balloon / Yes, the balloon reached an altitude of 30.3 km. / Mission Statement
0 / 2 / Payload shall store and collect data from our sensors / Partial success, one SD card successfully collected data while the other SD was corrupted. / Mission Statement
0 / 3 / The payload mass will not exceed 1.025kg / Yes, we had a final mass of 1.025 kg. / Mission Statement
0 / 4 / The payload shall be ready for launch by 1 December, 2012 / Yes, the payload was ready on time. / Mission Statement
0 / 5 / The team and project shall obey all safety precautions / Yes, all safety precautions were met. / Mission Statement
Level / Number / Requirements / Requirement Met? / Derived From
1 / 1 / The payload will be able to hold all electronics and sensors / Yes, the payload successfully held all electronics and sensors. / 0-R2/0-R3
1 / 2 / The internal temperature of the payload shall not drop below -10° celsius / Undetermined, the data was collected on the corrupted SD. / 1-R2/1-R3
1 / 3 / The payload shall contain a power source / Yes, the payload had a power source of eight 9V batteries. / 0-R2/0-R3
1 / 4 / The payload shall be constructed solely of foam core / Yes, the payload was created from foam core. / 0-R1/0-R3
1 / 5 / The payload shall contain two working Geiger counters / Yes, both Geiger counters were on the payload and working properly. / 0-R2/0-R3
1 / 6 / Geiger counters will be shielded with different materials / Requirement not met due to change of mission. / 0-R2/0-R3
1 / 7 / An American flag will be attached to the BalloonSat / Yes, an American flag was attached to our BalloonSat. / 0-R5
Level / Number / Requirements / Requirement Met? / Derived From
2 / 1 / The payload shall contain a heater / Yes, the payload did not contain a heater. / 1-R2/1-R3
2 / 2 / The Geiger counters will be connected to the Arduino microcontroller / Yes, the Geiger counters were connected to the Arduino microcontroller. / 1-R5/1-R1
2 / 3 / One Geiger counter will be used as a control for radiation measurement / Yes, a kit Geiger counter was used as a control for radiation measurement. / 1-R5/1-R1
2 / 4 / The structure will be sturdy enough to survive the ascent and descent / Yes, the structure survived the flight. / 1-R3/1-R4
2 / 5 / The Arduino microcontroller will be programmed to collect information / Yes, the microcontroller was properly programmed. / 1-R5/1-R1
2 / 6 / Arduino and carbon fiber tubes will each be used to shield one Geiger counter from radiation / Requirement not met due to change of mission. / 1-R5/1-R1/1-R6
3.0 Design
Structure
Aether shall be made with foam core, in a hexagonal shape, in accordance with the diagram. This shape was chosen due to the centripetal force that will keep the Balloon Sat equipment on the side of the satellite as it hurtles towards the earth. The design will protect the equipment from the whip effect as well. The whip effect is caused by the balloon bursting and the satellite hurtling back towards earth . The components of the satellite will be attached to the inside walls of the foam core design, using hot glue, velcro, duct tape, and electrical tape. To attach the BalloonSat to the balloon, the flight string will run through a plastic tube attached directly through the middle of the structure. This tube will be secured with two metal washers on the outside of the structure held together with hot glue, as well as a paperclip on the outside of each washer to ensure that the tube will stay in place. Half inch insulation will be glued to all the sides of the surrounding inside walls but will be altered to fit in all of the components. There will be several holes in the design to accommodate for a camera, four on/off switches, and three LED indicators, to show the equipment is working. Wires will be secured down with electrical tape. All parts of the satellites will be subjected to testing and modification accordance to the results of those tests.
Geiger Counters
Originally, our design included three homemade Geiger counters. The prototype counters were built following a schematic found online using disposable camera flash units.3 When the initial board did not work out well, we obtained a breadboard example and schematic (below) for a new, more complicated breakout board that would allow the Geiger counters to function properly. One Geiger tube would be not covered by any material, another would be covered with an aluminum tube, and the last with a carbon fiber casing. This would allow us to determine which, if any, material blocks radiation the best. However, due to difficulties with the sensitivity and design of the homemade Geiger counters, we decided to fly one homemade Geiger counter and one “off-the-shelf” Geiger counter built with a kit from Space Grant. Both of these Geiger counters were uncovered.
Using interrupt coding in Arduino, the counts the Geigers detects will be recorded to a mircoSD card. Due to the Arduino Uno only having one usable port for the interrupt coding, we split the Geiger counters so there was one per Arduino.
Arduinos
Two Arduino Uno boards were used for our BalloonSat. Arduino One had the humidity sensor, pressure sensor, internal temperature sensor (analog), accelerometer, and homemade Geiger counter and was connected to two 9V batteries. The sensors were all soldered to the SparkFun, SD card shield that was provided to us. The Geiger counter was attached by running wires along the sides of the payload. Arduino Two was connected to the external temperature sensor (analog) and the kit Geiger counter with three 9V batteries attached because the kit Geiger counter required an input of 9V versus the 5V needed for the homemade Geiger counter. Both items were connected to the Arduino through long wires that allowed them to be in the correct position for flight in the payload. Each Arduino was connected to an external switch and LED.
The design diagrams, pictures, and functional block diagrams are shown below.
3.1 Design Diagrams
Measurements are in millimeters_
3.2 Functional Block Diagram
Note: Different colors signify the separate systems.
3.3 Schematic
This is the Geiger counter final design schematic. Parts are identified below:
LM555: 555 timer
2N2222: Transistor
IRF640: Voltage Regulator
IN4007: Zener Diode
4.0 Management
Work will be divided among the each of the team members. All members of the team will lead/specialize in at least one of the subsystems (The lead position is in black, the assistant position is in white). The assistant position will entail checking and aiding the leads of the subsystem they are assigned to. Our schedule is made up of weekly meetings on Monday and Tuesday along with extra meetings for building, testing, and review preparation.
4.1 Team Positions
4.2 Schedule
Date / Meeting09/13/2012 / Team Meeting (8-10pm) (Weekly)
09/17/2012 / Team Meeting (8-10pm) (Weekly)
09/18/2012 / Team Meeting (8-10pm) (Design Complete)
09/24/2012 / Create Proposal (8-10pm)
09/27/2012 / Review Proposal Meeting (10-12am)
09/28/2012 / Turn in Proposal (4pm)
10/02/2012 / Presentations Due (7am)
Conceptual Design Review (9:30-10:45pm)
Team Meeting (8-10pm)
10/05/2012 / Authority To Proceed (9am-3pm)
10/18/2012 / Rev A/B and pCDR Presentation Due (7am)
Pre-Critical Design Review (9:30-10:45am)
10/23/2012 / Team Meeting (8-10pm)(Prototyping Design Complete)
10/28/2012 / Drop and Kick Test (7-8pm)
10/30/2012 / Whip Test (8-9pm)
11/05/2012 / Team Meeting (8-10pm)
(Final Testing Of Drop ,Whip, and Kick
Tests Complete and Confirmed )
11/06/2012 / Team Meeting (8-10pm) (All Hardware Required)
11/11/2012 / Hardware Tests (12-4pm)
11/12/2012 / Team Meeting (7-10pm)
11/13/2012 / DEMO – In Class Mission Simulation Test
Team Hours with Chris (5-8pm)
11/14/2012 / Team Meeting (6-11pm)
11/15/2012 / Cold and Power Tests (8-11pm)
11/16/2012 / Rev C Design Document Due (12pm)
11/27/2012 / Launch Readiness Review (9:30-10:45am)
Team Meeting (8-10pm)
11/30/2012 / Final BalloonSat Weigh-in (8am-1pm)
12/2/2012 / BalloonSat Launch (6:50am)
12/11/2012 / Final Presentation(6:45-9:00pm)
12/13/2012 / Final Design Document Due
5.0 Budget
Item / Quantity / Source / Weight / CostStructure
Foam Core / 1,596cm^2 / Gateway / 103g / $0.00
Aluminum Tape / 150cm / Gateway / 5g / $0.00
Hot Glue / 5g / Gateway / 5g / $0.00
Insulation / 1,000cm^2 / Gateway / 50g / $0.00
Carbon Fiber
Cap / 3cm^2 / Gateway / 30g / $5.00
Aluminum Cap / 3cm^2 / Gateway / 35g / $2.00
Hardware
Disposable Camera Flash Unit / 6 / MadScientist.com / 50g / $17.95
Geiger Tube / 10 / Ebay.com / 300g / $54.50
Geiger Parts (see
above list) / 21x3 / CU Electronics Store/J.S.Saunders / 30g / $32.79
Copper Wire / 3 m / McGuckin’s / 2g / $2.00
Heater System / 1 / Gateway / 100g / $0.00
Plastic Tubing / 1 / Gateway / 4g / $0.00
Cannon SD780 / 1 / Gateway / 130g / $0.00
Dry Ice / 5kg / Safeway / N/A / $12.00
Batteries / 20 (including tests) / Safeway / 185g (flight weight) / $30.00
Total / 1025g / $155.24
6.0 Test Plan and Results
6.1 Testing Schedule
Structure Tests
○Drop Test (10/28)
○Kick Test (10/28)
○Whip Test (10/30)
Hardware Tests
○Geiger Counter Test Pt. 1 (11/7 & 11/9)
○Camera Hardware (11/13)
○Arduino Sensors (11/13)
○Power (11/15)
○Cold (11/15)
○Geiger Counter Test Pt. 2 (11/26)
○Geiger Counter Test Pt. 3 (11/30)
6.2 Structure Tests
Drop Test
After completing the structure, we tested to see how well our structure would survive landing by dropping it off of multiple buildings. These buildings included the front balcony of the ITLL and the top of the DLC. The drop off the ITLL building ended in failure, our box was unable to handle the impact of landing and broke open. In order to simulate the weight of the hardware we placed rocks inside of it that were approximately the same weight as the components will be for launch. Our structure was holding weight to simulate the hardware that will be inside it. We concluded that our structure was sufficient enough to withstand the impact of landing.
Kick Test
We tested our structure to see how well it would survive a rough landing. To do so, we kicked our structure down a huge flight of stairs in the DLC. The weights were weighed to ensure the correct amount of weight was placed inside our box. Upon kicking the structure down the stairs the box encountered many of the same force it could experience in a rough landing. After the test we examined our structure. No major damages were incurred from the testing. We concluded that our structure was able to withstand the battery it may encounter upon landing.
Whip Test
Our final structure test was to ensure that our structure would stay intact during the descent. During descent, the BalloonSat will possibly encounter high magnitude G-forces. The purpose of the whip test was to ensure that the structure would hold and not rip away from the rope. The whip test actually included us attaching the structure to a similar rope and violently swinging it back and forth repeatedly to replicate the whiplash conditions it will be exposed to. We swung it in a variety of directions to ensure its stability. We concluded that our structure was fully prepared to encounter the violent G-forces experienced during descent and landing.
6.3 Hardware Tests
Camera Hardware
We tested our camera hardware by turning on the camera and running it for about an hour. When the hour was up we pulled out the SD card and plugged it into a computer to see if it recorded the pictures. The code on the camera worked perfectly and we were able to obtain many pictures. This test was run more than once, with the latest time being two days before payload turn in for flight.
Arduino Sensors
We tested our Arduino sensors and we have confirmed that the sensors work. The sensors do in-fact detect changes in their relative measurements. We calibrated our sensors before launch, so the data that we get back from them is accurate.
Cold
Our final test was the cold test. In this test we subjected the various sub- systems to extreme cold. This cold temperature was provided by two dry-ice blocks. Our BalloonSat was placed in between the blocks and set inside a cooler. In the cold test we only tested our Arduinos, camera, and heater because our Geiger counters were still not functional. The test was to last the duration of proposed flight time(approximately 2.5 hours). After the allotted time we removed our BalloonSat from the cooler. The satellite was very cold to the touch. We opened our box and soon discovered that our 9V batteries had died. This discovery was very disconcerting to us. However, the box was relatively warm inside, with our camera and heater being very warm to the touch. Even though the batteries died; we did find that the Arduino’s did retrieve data for about 45 minutes. According to the predicted flight time, the Arduino would have suffered the coldest temperatures during this 45 minutes. In conclusion, our systems could survive the extreme cold that would be experienced during flight.
Geiger Counter Test Pt. 1
By following the schematics and instructions online about hacking a flash unit of a disposable camera, we built circuits for the Geiger counters and soldered on the Geiger tubes bought from Russia. After completing the building, we brought 5 Geiger counters to a Physics Department Laboratory for testing. Art Klittnick was extremely helpful towards us, providing a source of radiation (thorium and uranium), power, and an oscilloscope to check if the Geiger counters were detecting radiation properly.
We connect one Geiger counter to 5V power and ground, and wired the output to an oscilloscope. The oscilloscope read the voltage spikes caused by radiation detection from the tube. However, the circuit was not well made because there was too much noise with the read out and we could not see spikes for more than a few seconds before the oscilloscope no longer showed any logical outputs. By testing the circuit with a Geiger tube that Mr. Klittnick had and knew functioned correctly from previous tests, we found that the circuit was not made well enough to use for radiation detection in our balloon satellite.