Delta IX
Balloon Satellites
Final Report
Gateway to Space
Spring 2003
Tyler Redick
David Kaplan
Harold Sampson
Matt Syme
George Jerdak
Callan McMahon
Delta IX
Balloon Satellites
Spring 2003
Outline
1. Introduction
------------------------------------------------------------------------ 3
2. Experiments ------------------------------------------------------------------------ 4
a. Decibel Circuit -------------------------------------------- 4
b. Camera ------------------------------------------------------ 5
c. Temperature and CO Sensors ------------------------- 5
3. Construction ------------------------------------------------------------------------ 5
a. Computer Aided Design -------------------------------- 5
b. Design Features -------------------------------------------- 6
c. Materials ----------------------------------------------------- 7
d. Launch Day Stipulations --------------------------------- 7
4. Data Analysis ----------------------------------------------------------------------- 7
a. Resonance Experiment ------------------------------------ 7
b. CO Collection ----------------------------------------------- 12
c. Imaging -------------------------------------------------------- 13
d. Temperature -------------------------------------------------- 14
5. Conclusion --------------------------------------------------------------------------- 15
a. Proposal Differences ---------------------------------------- 15
b. Mass and Cost Budget -------------------------------------- 16
c. Lessons Learned --------------------------------------------- 16
d. Message to Next Semester -------------------------------- 17
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Introduction:
Team Delta IX’s mission was rather simple. The project was to build a
balloonsat that could withstand the extremes of the upper atmosphere and to
perform two experiments during the ascent and decent to and from roughly
100,000 feet. Our team posed two questions which we sought out to discover
about the atmosphere; first, “Does carbon monoxide significantly exist at 100,000
feet?” Secondly, “What were the effects of sound in an environment containing less air
than sea level?” Hence, our two experiments were decided to discover the
amounts of carbon monoxide in the upper atmosphere and to record the changes
in sound resonance as our balloonsat was in flight. We had also hoped to
capture the Earth and balloon in pictures, record external and internal
temperatures, and measure the ascent/decent rates of our balloonsat.
Coordinated with the course Gateway to Space, our balloonsat held
requirements it needed to meet. First, the mass of the balloonsat could not
exceed 500 grams and the final cost of the balloonsat was not to exceed 250
dollars. Secondly, we were supposed to perform two experiments during the
flight of the balloonsat on launch day. Third, our balloonsat was expected to
take photographs of the Earth and the balloon while it was in the upper
atmosphere. Next, the total internal volume of our balloonsat was not supposed
to surpass 1500 cubic centimeters. Finally, the balloonsat was supposed to record
the external temperature, internal temperature, and ascent/decent rates of the
flight; of which, the internal temperature was not to fall below zero degrees
Celsius.
In general, most of the requirements were met and accomplished by Delta
IX’s payload. Our total internal volume measured out at just less than 1500 cubic
centimeters; below our allotted volume. Also, the cost of our balloonsat was
close to 100 dollars short of our limit. As for the launch itself, we successfully
record the ascent/decent rates and found that the flight peaked at 93,000 feet.
The lowest external temperature recorded at about –60 degrees Celsius; the
internal temperature, however, did fall below zero degrees Celsius and gave a
lowest reading of –10 degrees Celsius. As for our two experiments, we were able
to successfully return significant data readings for the amount of CO in the
atmosphere and the fluctuations of sound resonance at high altitude in the form
of volts.
Delta IX did, however, fail to meet a few of the given requirements. For
example, the final mass of our balloonsat was approximately 577 grams; over the
500 gram maximum. We unfortunately did not photograph the Earth and
balloon during its flight. And finally, the internal temperature of our balloonsat
did not stay above zero degrees Celsius; again, it returned a reading of –10
degrees Celsius.
The basic proposal and mission of Delta IX was overall successful.
The balloonsat flew, recorded data, and stayed intact for the duration of the
flight. We were able to plot and analyze excellent data within hours of the
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balloonsat recovery. For the greater part, and as you will soon discover, Delta
IX’s balloonsat can be considered an overall success.
Experiments:
Decibel Circuit
We began to design our experiments as soon as we had finalized on them.
Some took careful planning and hours of effort, while others were fairly
straightforward. Our decibel circuit by far took the most time and effort,
while the camera took simple construction, and the temperature sensors
and Carbon Monoxide sensor only required simple initialization.
The Decibel Meter circuit was by far the most complex of our systems, and
required the most care and effort in design and construction. We began
by researching the ways to record sound, specifically loudness. We
considered a digital voice recorder, and a number of other devices that
would have captured the entire sound waves digitally, including the
frequency. However, we were not concerned with the frequency of the
sound, only the amplitude. Thus we limited ourselves to a device the
strictly recorded decibel values.
After some consideration, we determined that commercial decibel meters
were either too bulky to fit in our cube, or too complicated to strip down.
Thus we decided to build our own.
We began searching for schematics for this type of circuit on the internet.
We finally found exactly what we were looking for in the form of an
“Audio decibel level detector” design for cellular phone applications,
schematic AN1991, from Philips Semiconductors. Matt Syme, our team
member with the most electrical engineering experience, designed our
circuit, taking into account AN1991, as well as power needs for our
heating elements, and the power needed to run our speaker. Matt spent
hours in the ITLL Electronics Center, designing the circuit with the
program ExpressPCB. We finally printed, drilled, and soldered our
circuit, and the board itself was complete. The board gives a DC voltage
output to the HOBO data logger, and the circuit utilizes a diode to bypass
the signal to the HOBO if the voltage reaches a level of above 2.5 volts.
Anything above this voltage could damage the HOBO.
After soldering the speaker, microphone, and HOBO cable to the circuit,
and protecting the board with electrically isolative plastic so as to prevent
short circuits, we were able to test the circuit.
Our first tests of the circuit showed no voltage output at all, and we were
baffled. However, after hours of testing in the Electronics Lab, we
determined that we needed to reverse the direction of one capacitor, and
also use a stereo cable to interface with the HOBO instead of a mono cable.
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After we implemented these changes, the circuit performed flawlessly in
our tests.
Camera:
Our next system was the camera, which needed to image both the balloon
and the earth in flight. We considered many solutions to this requirement
before coming to our final design. We considered a fisheye lens to get one
wide field image that would include the balloon and the earth. However,
these lenses proved to be more expensive than our budget could afford.
We considered a convex mirror that would accomplish the same thing as
the fisheye lens, however, we would need to place the camera at some
distance from the mirror, as not to obstruct too much of the view. We
determined that this was impractical, as it would require a lot of volume.
We came to the conclusion that a mirror to split the image was the best
solution. We would attach a mirror at a 45 angle on the outside of the
camera in front of the lens. The mirror would be positioned in the middle
of the lens’s field of view, such that half the image would be straight
ahead, and half would see through the mirror.
Temperature and CO Sensors:
Our last two systems, the temperature sensors, and Carbon Monoxide
sensor, required relatively little design. Since there was no construction
involved, we simply need to plan where they would fit inside the satellite.
It was important for us to take into consideration the weight and volume
of the Carbon Monoxide sensor. The sensor weighed 132 grams, and took
up a significant volume inside our satellite. We secured the sensor with
Velcro, which held very tightly. Our temperature sensors were integrated
into the small HOBO. The internal temperature sensor was housed within
the HOBO itself, and thus needed no implementation, while the external
sensor simply needed a hole in the foam core shell to plug into the HOBO.
We planned for the small HOBO to be housed above the Carbon
Monoxide sensor, and also secured with Velcro.
Construction:
Computer Aided Design:
The entire satellite was originally designed with a digital design program
called Solid-Works Pro. The advantages to this were that our team could
have a completely “built” version of our satellite before it is actually built.
This allowed for easy design changes if any were necessary after all the
experiments and internal components were finalized. The program also
allowed the team to arrange the internal components in a way that would
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maximize space and allow access to all the components with minimal
work. The following is a picture of the digital design.
Design Features:
Imaging: In order to prevent the lens of the camera from freezing, our team
designed the satellite to hold the entire imaging system internally. The
team was required to image both the balloon, and the earth in flight, so
the imaging lens was divided in half, and a mirror was placed over the
upper half. The mirror deflected the image at a 90 degree angle, effectively
taking two pictures in one. Plexiglas windows were inserted into the
cube’s shell to allow the two angles of imaging to see outside of the
satellite.
Sound: Like the camera, the speaker and microphone system needed to be
inside the satellite to prevent freezing of either of the components. Both
the speaker and Mic. pointed outward, so as to emit, and collect the sound
through the atmospheric medium in which the satellite was currently
flying through.
Heating: Ceramic resistors hooked up to a 12volt battery were used to
create heat inside the satellite. These resistors were placed next to the CO
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sensor and in amongst the various circuit boards that controlled the
satellite’s many systems.
Materials:
Foam core was used as the structure for the satellite as opposed to an
aluminum shell. The advantages of Foam core were its weight and cost.
Foam core is considerably less massive than aluminum and because our
satellite had such tight weight restrictions, it allowed for more of the mass
to be used for the components rather than the shell. Foam core was much
cheaper and easier to handle and manipulate than aluminum. The only
downside to a foam core shell is that it is not as strong as an aluminum
one. That concern was nullified however when we suffered no structural
damage after several shake tests and still no damages after the flight its
self.
Launch Day Stipulations:
Because of the nature of the launch, the team was required to seal the
satellite an hour prior to the launch. This means that the team didn’t have
access to the internal components. In order to prevent unnecessary power
usage for that hour, it proved useful to put switches on the outside of the
satellite, so that even if the satellite is sealed, the team could activate the
internal components just before the launch actually occurred.
Data Analysis:
Resonance Experiment:
We retrieved remarkable data from our Decibel Meter Circuit.
Considering this type of experiment has never been attempted in this
class, we were amazed that the Hobo recorded all the data that we
expected to collect, and that the data is also very reagent.
Below is a plot of the voltage returned from the circuit to the Hobo, with
respect to time: (see next page)
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One can see that we obtained data for the entire duration of the flight,
unlike our Carbon Monoxide data which stopped recording when the
temperature dropped too low. There is no evidence of any type of corona
arcing or damage to the circuit.
We will begin by examining each portion of the voltage data. One can see
the spike shortly before 9:00 am when we turned the circuit on and the
speaker began emitting its tone. Before this point, the Hobo registers 1.4
volts before the circuit was turned on, and then jumps up to 2.50 volts.
The balloon was launched shortly after, and began to gain altitude. We
then see the voltage begin to drop off rather noisily with many spikes;
however, on average it might resemble an exponential curve as we will
see below. Then, at a time closest to 10:10:12 am, the balloon bursts, and
begins to fall. Just before the burst, the voltage had dropped to around
2.05 volts. However, at the same time the balloon bursts, the voltage
jumps back up to 2.50 volts. We believe that this spike can be attributed to
the loudness of the wind due to the high velocity at which the balloon is
falling initially. The balloon lands around 10:22 am and at this time in the
plot above the voltage drops back down to below 1.40 volts. This drop is
likely attributed to the way in which our satellite landed. Because we did
not retrieve the satellite as soon as it landed, the speaker kept emitting its
tone even after touchdown. When we recovered the balloon, we did not
think it relevant to note the position on which the satellite landed. The
satellite most likely landed on the foam core side that houses the speaker
and microphone. This would have blocked the sound from the speaker or
microphone, and thus the circuit would have returned a low voltage to the
Hobo in the absence of any sound. Next, around 10:35 am we see another
spike back up to 2.5 volts. However, the balloon had already landed by
this point and all data after the balloon’s touchdown is irrelevant. This
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spike may be due to our team recovering the satellite, or the strong winds
may have blown the satellite such that the microphone was no longer
blocked.
In our mission statement, we wondered how altitude, and specifically air
pressure/density, affects sound waves. Below is a plot of air pressure
versus altitude (source: USA Today, Aerodynamics for Naval Aviators).
Pressure vs Altitude
Pressure (in Hg)
30
25
20
15
10
5
0
0
20000
40000
60000
80000
100000
Altitude (ft)
Using Microsoft Excel, we calculated an exponential best-fit curve to the
plot above. The equation is: y(x) = 30*e(-4E-5) x. We then isolated the
relevant portion of the voltage data, that is, the data beginning just before
the balloon launch, and ending just before the spike when the balloon
bursts.
That plot of the relevant voltage data versus time is shown below. Along
with the data points, we used Excel to plot a best-fit curve of the data.
However, Excel refused to plot an exponential best-fit. Rather, it would
only plot and compute a power series best-fit curve, whose function is
displayed below as y(x) = 5.3395*x-0.0843. This best-fit function is of no use
to us because we cannot compare it to the exponential function of pressure
with respect to altitude.
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Voltage (volts)
Voltage vs Altitude
2.5
2.45
2.4
2.35
2.3
2.25
2.2
2.15
2.1
2.05
2
y = 5.3395x-0.0843
0
20000
40000
60000
80000
100000
Altitude (ft)
However, in another plot we showed in one graph our data
corresponding to voltage, external temperature, as well as the air pressure
(from two plots above) all with respect to altitude. Due to the fact that
pressure varied between 30 inches of Mercury and zero, while voltage
fluctuated between 2.5 and 2.05 volts, we needed to multiply the voltage
by a scale factor in order to plot it on the same graph as the other data. To
do this, we subtracted all voltage values by 2.05 volts, and then multiplied
them by a scale factor of 60. Thus the initial voltage value of 2.5 volts
appears on the graph below at 26.1, near the starting value of pressure,
which is at 30. Although the voltage data is scaled here, it the data points
should remain consistently located with respect to each other. However,
when we tried to plot a best-fit curve for the voltage data on this plot,
Excel allowed us to plot and compute a best-fit curve that was
exponential. We can see this curve below, along with the best-fit curve
corresponding to the pressure data. The equation of the best-fit curve that
Excel computed for the scaled voltage data is y(x) = 27.81*e-(4E-5)*x. Recall
that the equation representing pressure with respect to altitude is y(x) =
30*e(-4E-5) x. Thus one can see that the best-fit equations representing
voltage and pressure are remarkably similar, except for a difference of 2.19
in the coefficient of e in the equations. This leads us to believe that
volume of sound decreased with altitude in the same way that pressure
does; it drops off exponentially.
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It does not seem that temperature has much, if any, affect on the voltage.
One does notice however, that below roughly 30,000 feet, the voltage data
points linger around 2.5 volts (26 unit-less units in the plot above). After
30,000 feet most of the data points center around 2.075 volts (1.5 units in
the plot above). It might seem at first that temperature could have
something to do with this effect because there is a minimum temperature
at around this altitude. However, as the temperature rises again as the
balloon nears burst height, the same effect is not observed. Thus we can
reasonably conclude that temperature has a negligent effect on the volume
of sound in the upper atmosphere.
The effect of data points lingering close to the voltage values of 2.5 volts
and 2.075 volts, but not in between is nonetheless a peculiar effect, which
may have an explanation. If the frequency of the tone emitted by the
microphone were to coincide with some resonant frequency of the foam
core box, or some component within the box or microphone itself, it could
serve to explain the observed phenomenon. If any component of the
satellite (such as its structure) were to resonate at the same frequency as
the speaker, it would amplify the sound from the speaker, and also the
sound from all overtones of the frequency. In the plot above, we are likely
looking at the first overtone of this frequency in the portion below 30,000
feet. The structure or some other component of the satellite would have
amplified this sound, raising the volume recorded by the microphone to
the observed 2.5 volts. As the balloon rose and the atmosphere became
less dense, there would have been less air for the resonating sound to
travel through to reach the microphone, and the resonating sound would
have become quieter. It this point, perhaps the resonance would have
dropped down to the fundamental overtone, resulting in the line of data
points clustered around 2.075 volts. It is a simple theory, and we do not
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have the resources or knowledge to evaluate its worth, however, it seems
plausible. It is clear nonetheless that the volume did drop as the pressure
decreased.
In summary, our Decibel Meter Circuit recovered excellent data which
indicates that volume in the upper atmosphere falls off exponentially with
respect to altitude. The plot below makes this clearer. Below, we see
voltage plotted versus pressure. Above we saw that the exponential
functions for pressure and voltage as a function of altitude were similar in
form. They seemed to have the same exponential curve, only different
starting values. Thus, when we plot two exponential functions against
each other, we expect to find a linear line, which is just what we have
below. Again, we used Excel to find the linear best-fit line, the equation of
which is displayed on the graph.
3
Voltage (volts)
Voltage vs Pressure
2.5
y = 0.0199x + 2.0718
2
1.5
1
0
5
10
15
20
Pressure (inches Hg)
25
30
Using the best-fit equation from the plot above, we can summarize our
data with the equation: Volume (pressure) = 0.0199(Pressure) + 2.0718
where pressure is in units of inches of Mercury, and volume is any relative
linear scale (such as voltage). It is important to note that voltage cannot
represent decibels, as the decibel scale is logarithmic. That is to say, what
sounds twice as loud to the human ear will be recorded as ten times as
loud by a microphone, or a circuit such as ours.
CO Collection:
After launch, the CO hobo collected a flat-line of data as can be seen in the
graph below. This is not incorrect collection of data after further research
was done. The CO content in the upper atmosphere is on the order of
.12ppm (parts per million) and our CO collector can only take readings of
densities .5ppm or greater. It isn’t that there isn’t any CO in the upper
atmosphere; it’s that our collector wasn’t sensitive enough to collect it.
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The experiment was generally a success, but it was known before hand
that the CO sensor would cease functioning if the internal temperature
dropped below -10degrees Celsius. The graph below of the three CO
collectors and the internal temperature (dark blue) shows that at the
minimum temperature spike (where the temp dropped below -10degrees)
the data from the CO hobo was no longer recorded. This was predicted
and does not negate the data collected before the hobo shut off.
CO vs. Internal Temp
25
20
Temp C/Co (ppm)
15
10
5
0
-5
-10
Time
Imaging:
Upon retrieval of our satellite, we discovered that the camera had taken
no pictures during the flight. The matter of explaining this failure is
simple. Most modern electronic devices are programmed to shut
themselves off if left inactive for a sufficiently long period of time. We
were aware of this fact, and thought we had dealt with it during the
design and building phases of the project. We were aware that with a
timing circuit to trigger the camera, the camera may turn off during the
inactive interval between clicks of the circuit. We bench tested the camera
to make sure that it would not turn itself off while left inactive for a period
of five minutes. Our timing circuit triggered the camera every three and a
half minutes, thus we figured that five minutes ought to be a sufficient
test. The camera did not turn off after five minutes of inactivity, and we
did not pursue the matter further.
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In reality, we neglected to take into account our launch day procedure.
On launch day, we initialized our Hobo’s, turned the camera on, and
taped the satellite shut tightly. The then would simply need to flip two
switches immediately prior to launch. One switch would turn on power
to the decibel circuit, the other would turn on power to the heating circuit
and the camera’s timing circuit. We did not consider what would happen
to the camera in the time that the satellite was taped shut, and the
switches were off. On launch day, most groups came well prepared,
including us. Thus we were able to tape our satellite closed early, and had
nothing to do but wait. It turned out to be at least an hour from the time
we taped the satellite shut to launch when we turned the switches on. We
believe that after about forty-five minutes or so, the camera timed out and
turned itself off due to inactivity. When we turned the timing circuit on,
the circuit functioned properly, however, the camera had shut off and
thus closing the trigger had no effect.
This failure could have easily been prevented. It was a simple human
oversight. We did not think to consider such a scenario as this occurring.
Had we done so, the failure of our camera to collect data could have been
avoided.
Temperature:
Internal and External temperatures were measured using the standard
HOBO data logger provided by our class. The plot above illustrates the
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change in the internal and external temperatures over the period of the
flight. Landing was at approximately 10:45am, so the chart shows about
an hour of post-flight warming that occurred while the team was in route
to the retrieval site. The heating circuits worked well in that they kept the
internal temperature well above the external environment’s temperature.
At the maximum altitude, the external temperature experienced the
minimum at about -58degrees Celsius, while the internal temperature only
fell to approximately -11degrees Celsius. The flat-line just before the
minimum peaks in both the internal and external temperatures indicates
where the satellite passed through the dense layer of air above the lower
atmosphere. It is often recorded that this area is a warm pocket of stable
temperatures and our data shows the same. The temperature experiment
was a success in that we got back solid, and predicted results from the
flight.
Conclusion:
Proposal Differences:
In general, team Delta IX was able to follow our proposal for our
balloonsat significantly close and carefully. The experiments proposed
were carried out successfully, the plan that solved the problem of how to
take pictures of the Earth and balloon were the same in our final payload,
and the small design features like the location of the tether on the
balloonsat were the same throughout the construction period. Probably
the greatest difference from our proposal to our finished payload,
however, was the decision to cut our carbon monoxide and oxygen
experiment into just a carbon monoxide experiment. The reasoning
behind this was simply because of our restriction on cost and mass. The
HOBO oxygen sensor would not only take up too much mass and volume
in our balloonsat, but also held a price tag well above the team budget
limit. Consequently, the CO and O2 experiment was modified into just a
CO experiment; which we were able to attain the HOBO sensor through
Chris Khoeler of the University of Colorado Space Grant program.
Another change in our proposal could be found in the dimensions of our
actual balloonsat. Originally, Delta IX planned for our balloonsat
dimensions to be that of a cube and contain support struts to help with
structural integrity and payload mounting; however, we later found out
that because of the dimensions of our CO sensor, the balloonsat would
have to compensate and instead take the form of a rectangular box with
no support struts. The CO sensor itself actually became the payload
anchor in that it had all the other components Velcroed to it. This
adjustment actually had both positive and negative overall affects to our
final payload. It allowed for more room for our components and also
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more insulation; however, it was heavier design than that of a simple cube
design. Finally, the addition of switches to turn on the components of our
balloonsat from the outside and the removal of steel crossbars because of
the weight limit concluded the changes in design.
Mass and Cost Budgets:
The team’s mass budget was underestimated throughout the semester.
The initial mass estimates of Delta IX’s balloonsat totaled below the given
requirements at about 475 grams. The mass estimates gradually increased
until it peaked out at the measured 577 grams on the day of launch.
Surprisingly, the batteries turned out not to be the primary mass devices
in our balloonsat; at the day of launch, it only had two 9V lithium batteries
weighing 46 grams each, and two 12V camera batteries weighing close to
30 grams each. The majority of our mass could be contributed to both the
CO sensor, which weighed about 132 grams, and the camera/timing
circuit system, which weighed about 157 grams. The other mechanisms of
the final balloonsat mass included a foam core shell (58 grams), HOBO
data logger and external temperature cord (24 grams), speaker (10 grams),
microphone (5 grams), and decibel meter circuit (15 grams). The rest of
the mass was in the form of electrical wires, packaging tape, and fiberglass
insulation.
Delta IX’s cost budget was well under the allotted cost budget given by
the restrictions of the class. The most expensive component of the
balloonsat was the audio decibel meter system; however, Delta IX was
able to contact Philips Semiconductors Incorporated and receive every
part needed to construct the circuit in the ITLL electronic laboratory as a
donation to our project. With the decibel meter components donated to
our team, most of the money used for the balloonsat was primarily for
lithium batteries, film, foam core, mirrors, and the breadboard needed to
build the decibel meter circuit on. Hence, the total cost for Delta IX and
their balloonsat was approximately one hundred and seventy dollars; well
under our two hundred and fifty dollar limit.
Lessons Learned:
The experience of designing, building, launching, and retrieving our
payload all consequently gave everyone in team Delta IX opportunities to
learn from their mistakes.
Group dynamics, design and planning skills, and for some of the team
members simple circuit building were some of the many lessens learned.
Planning and group dynamics were probably the most evident lessens
learned throughout the entire experience. Delta IX held good overall
group unity and team agreement on all of the different characteristics of
the balloonsat. The team members of Delta IX all could take their
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experiences with this project as a kind of reference to what kind of teams
we would all like to participate with in the future. Also, our team
planning and design of our payload was all done fairly well. We did,
however, encounter some problems as the launch day deadline
approached; for example, the final mass underestimates where to place
the switches for the several systems inside the balloonsat. One lessen we
could take out of this experience because of our complications would be to
expect bumps in our next teams projects we will encounter here in college.
Since the time spent before launch day was primarily in the electronics
laboratory building the decibel meter circuit, several team members also
gained some experience and knowledge working with electrical circuits.
In particular, working with soldering irons, testing the circuit, and
adjusting the circuit to perform with different types of batteries all could
be considered as electronic laboratory experience and almost like a short
and basic class on electrical circuits. It was an excellent way to gain the
hands-on familiarity we will all undoubtedly need in the field of
engineering sciences.
Message to Next Semester:
As a message to next semester, Delta IX advises any future groups to start
early planning, building, and testing their balloonsats. Expect to have
components not work as planned before launch and be prepared to
possibly adjust and modify your original design to fix them. The best way
to find out these types of problems before launch is to simply test your
payload systems with freezer tests, whip tests, and run time tests. Also,
we found that our team had not anticipated how hard it would be to meet
the mass requirements. Hence, we would advise you to always be looking
for a way to cut the overall mass on your balloonsat. Finally, we all
thought that one of the better moments during the semester was the
balloonsat launch and recovery. It was definitely a proud moment to see
your balloonsats both up in the air and on the ground once you chase
them all down. So if you can make the launch and participate in the
chase, don’t pass up the chance.
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