16 September 2010
Payload Proposal
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Colorado Space Grant Consortium
GATEWAY TO SPACE
FALL 2010
BALLOON PAYLOAD PROPOSAL
Team Khufu
Members: Henry Shennan, Chelsea Donaldson, Graham Risch, Jennifer Nill, and
Jonathan Lupkin
16 September 2010
Revision 0
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Payload Proposal
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1: Mission Overview
This satellite will be equipped with a magnetometer, as well as thin solar films attached to a data
collector. The purpose of the magnetometer is to measure how magnetic fields change as elevation
increases. We expect to find a change in magnetism as the balloonSat rises through the atmosphere.
Just as the different levels of the atmosphere affect temperature, we are going to measure the effects of
the levels of the troposphere on the magnetic field around the satellite. If we consider the earth as a
point charge, and the satellite as another, then the data we can expect to collect will follow Coulomb’s
law, which states that the electromagnetic force will decrease in an inverse square relationship as
elevation increases.
The solar panels placed outside of the satellite will convert solar energy to electrical energy, which will
then be measured in watts. We can use this data to analyze how solar energy varies in each layer of the
atmosphere. Because of money and technological restraints, we will utilize photovoltaic solar cells,
which use a silicon phosphorous material in which easily moveable electrons create an electric current
when struck by photons from the sun. The atmosphere is known to refract light, which can affect the
energy output of a solar cell. Measuring the solar intensity throughout the atmosphere will allow us to
locate the optimum altitude for solar energy collection.
In conjunction with the solar panels, we will also measure UV radiation through the use of photodiodes.
The photodiodes will measure UV radiation in the form of watts as well. The ozone has been proven to
block some UV rays, and by comparing where the UV radiation is strongest with the electrical output of
the solar cells, we can determine the role ultraviolet light has in solar energy collection. It stands to
reason that the more photons there are, the more energy is radiated by the sun. We aim to prove the
correlation, if there is any, between atmospheric conditions and different forms of electromagnetic
waves. By conducting these experiments simultaneously, we will be able to isolate which variable is
affecting our data, since there are many factors-- such as temperature and weather-- that can alter the
mission’s results. This mission will allow us to perform a comparative analysis of electromagnetics in the
atmosphere.
In addition, we will use a HOBO data collector to measure temperature inside and outside the satellite
and relative humidity. This will allow us to record how climate changes throughout the atmosphere. A
camera will also be mounted on the satellite to track our flight path visually. One adjustment that will
need to be accounted for is the effect of extreme temperature on the solar panel and UV photodiode.
Temperature affects the resistance of materials, and therefore modifications must be made to ensure
the accuracy of the data collected. We can monitor just how much the temperature is affecting our
results by plotting how the temperature changes throughout the flight.
Using all of the data collected, we can form a correlation between temperature, altitude and
atmospheric conditions and UV, magnetic and solar strength.
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2: Design and Technical Overview
2.0: Design Description
The structure of will consist of a triangular box constructed from 0.125” foam board, reinforced along
the exterior edges with Aluminium tape, and insulated with 0.25” foam insulation. Structural joints will
be made by bonding the foam board with hot melt adhesive. The balloon tether line will be run through
a PVC tube along the center of gravity of the craft and will be fixed in place through the use of knots at
either end of the tube and protected using rubber bushings.
Data collection will be carried out by three separate subsystems: the HOBO unit, which will record
internal and external temperature and internal humidity; the digital camera, which will record images of
the ascent, descent, and of Earth’s curvature at predefined intervals for the duration of the mission; and
by the Arduino microcontroller, which will record data from the onboard sensors to flash memory. The
intervals at which the camera takes photographs will be controlled by a cracked version of the camera
firmware.
The primary mission payload will consist of two UV photodiodes, operational over the 20-350nm
wavelength range, four photovoltaic cells, and a magnetometer. The secondary mission payload will
consist of the camera and the temperature and pressure sensors onboard the HOBO. The photodiodes
will be used to collect data on the intensity of incident ultraviolet radiation at various altitudes, and will
be compared to data collected from the photovoltaic cells. The efficiency of the encapsulated
photovoltaic cells will be tested under the varying atmospheric conditions as the balloon-sat rises
through the atmosphere by measuring the power they collect. The magnetometer will be used to
characterize Earth’s magnetic field and to look for minute changes in the magnetic field as a function of
altitude.
2.1.1: Testing
The first round of testing will consist of tests on all of the individual components to ensure that they
function properly. Components will be tested according to their manufacturer’s instructions, and will be
tested in conditions consistent with what they will experience during the mission.
The second round of testing will be conducted on the subsystems. The magnetometer will be tested
while in its final configuration and the results will be compared to the earlier tests in which the
instrument was isolated in order to determine if onboard electronics will cause unacceptable levels of
interference (above) within the instrument. The external structure of the craft will be tested for integrity
by first conducting drop tests from a height of 20m, and then by being spun on a 1m cord at a minimum
of 50rpm. Those tests will only consist of the structure with representative weights replacing onboard
instruments. If any single component or subsystem fails a test, it will not be integrated into the larger
subsystem (or craft as a whole).
The final round of testing will be tests on the entire craft complete with electronics. These tests will
include, at minimum, a vibration test to simulate atmospheric buffeting, a temperature test to simulate
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temperatures down to 253K, and a full mission simulation. The temperature test will be achieved by
packing the craft into an insulated container with 100-300g of dry ice while the electronic systems are
running. Temperatures will be monitored from outside the external container using either a digital
thermometer or an additional HOBO device.
2.1.2: Data Analysis
After recovery of the satellite, data recorded in the flash ROM of the Arduino microcontroller will be
downloaded from that device using a USB cable to a laptop computer running the LabVIEW
instrumentation suite produced by National Instruments. Data will be exported from LabVIEW to
Microsoft Excel and analyzed along with data collected from the HOBO using Onset’s HOBOware
software.
2.2: Requirements Met
The total mass of the craft with payload is projected to be 750g (with a mass allowance of 100g. For
details, please see section 2.4), within the 850g limit set by the requirements in the RFP. Our design
includes the HOBO, Canon camera, internal heater, and temperature sensors mandated by the
requirements, and satisfies the requirement that the craft be constructed of foam-core board. Our
budget does include a $50 lump sum for spare parts and damaged part replacement, and still meets the
requirement that the total budget be under $300. The craft is designed to be reusable, and will include
identification and an American flag on an exterior surface. Finally, onboard heaters will ensure that the
internal temperature of the craft remains above 263K and a central PVC tube with rubber bushings will
ensure that the tether is not damaged during the mission.
2.3: Safety Observations
While constructing and testing this satellite we will observe proper safety precautions as outlined by
Professor Koehler and as described on the ITLL safety sheet. Work with soldering irons will take place in
a well-ventilated area and diligence will be exercised to prevent burns and solder overflow and
sputtering. During construction of the electronic subsystems ESD precautions will be observed; all
members working on the microcontroller, sensors, and magnetometer will be required to wear
antistatic bracelets properly connected to a common ground. In addition, wiring of key electronic
components will be checked at least twice prior to the application of current in order to both safeguard
the electronics and prevent accidents due to component malfunction and/or failure. Finally, both the
drop and whip tests will be conducted in broad daylight under favorable weather conditions, and by at
least two people: one to conduct the test, and the second to spot him or her. Both team members will
be required to wear helmets for the duration of the tests. Finally, any tests involving dry ice will be
conducted with the use of gloves and safety glasses to prevent contact burns and injuries due to
fragmentation of the dry ice.
2.4: Necessary Components
Part
Dimensions
Supplier
Cost
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Arduino Nano
HOBO H08-004-02
Canon A570IS digital camera
Heating circuit
9V Batteries and 5V regulator
Foam Board and Foam insulation
Camera Timing Circuit
External switches (x3)
PVC pipe with rubber bushings
Low Cost–High Output
Encapsulated Solar Cells (x4)
UV Photodiodes 20-350nm (x4)
MicroMag 3-Axis Magnetometer
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10x18x45mm, 10g
SparkFun Electronics
68x48x19mm, 30g
GTS
45x75x90mm, 220g
GTS
10x50x50mm, 100g
GTS
<35g
GTS
See section 3.5, 150g
GTS
Replaced by camera firmware, N/A
5x5x20mm, 15g total
GTS
10x350mm, 15g
McGuckin’s Hardware
26x45x7mm, 80g total
Edmund Scientifics
$18.95
-
5x5x5mm, 20g total
25x25x19mm, 10g
$80.00
$59.95
2.5: Craft Design
Figure 1: Satellite, exploded view
Figure 2: Satellite, flight configuration
Boston Electronics
SparkFun Electronics
$3.55
$15.80
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2.6: Functional Block diagrams
Batteries:
(9V with 5V
regulator)
switch
Microcontroller:
Arduino Pro Mini
328- 5V/16MHz
Magnetometer
Camera:
Includes power
source (AA batteries)
and data storage
(flash memory)
Flash ROM
switch
Photovoltaic
Cells
switch
IR Photodiodes
Heater
Timing Circuit
Humidity
HOBO
External Temperature
Internal Temperature
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Payload Proposal
3.0: Proposed Project Schedule
design complete
9/16/2010
acquire all hardware
Magnetometer sensor test
prototyping design complete
9/28/2010
9/30/2010
10/4/2010
DD Rev A/B and CDR
presentation
10/5/2010
cold test complete
Drop test
Whip test
10/12/2010
10/12/2010
10/12/2010
testing final design complete
mission simulation
10/26/2010
10/28/2010
LLR presentation and DD Rev C
Weigh In
final presentations due
design document Rev D due
design Expo
Hardware Turn in
11/2/2010
11/5/2010
11/30/2010
12/4/2010
12/4/2010
12/7/2010
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3.1: Team Organizational Chart
Chelsea
Team Leader
Jonathan
Structral Design
Henry
Graham
Jen
IT/Programming
Manager, Systems
Integration
Solar Panel
Experiment Design
UV Probe Experiment
Design
Budget Manager
3.2: Team Member Descriptions
Name
Chelsea
Donaldson
Jennifer
Nill
Jonathan
Lumpkin
Henry
Shennan
Duty
Structural Design, Payload Assembly
Systems Integration and
Programming
Woodshop Skills
good listener and
innovative ideas
Technical and
computer skills
Graham
Risch
Structural design, Budgetary
Management
Organization and
building skills
Team Leader
Skills
Leadership and
good imagination
Phone number
970-331-6409
303-241-7143
Testing and Design Troubleshooting
970-669-8776
303-564-7575
678-463-1374
3.3: Budget
Graham will be in charge of ordering components and ensuring that the project remains within the
stated maximum budget of $300.
Component Expenses
Part
Arduino Nano
Supplier
SparkFun Electronics
Cost
$18.95
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PVC pipe with rubber bushings
McGuckin’s Hardware
$3.55
Low Cost–High Output Encapsulated Solar Cells (x4)
UV Photodiodes (x4)
MicroMag 3-Axis Magnetometer
Testing Expenses
Dry Ice
Batteries: 9V
Edmund Scientifics
Boston Electronics
SparkFun Electronics
$15.80
$80.00
$59.95
Safeway Grocery
McGuckin’s Hardware
$10.00
$20.00
Allowance for spare parts and damaged part replacement
-
$50.00
Total Expenses
$258.25