Balloon Assisted Stratospheric Experiment

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Balloon Assisted Stratospheric Experiment
By Kayleigh Smallwood, Monica Hodgkiss, Holly
Roberson, Mike Wellington, Mitchell Parks,
Tyler Statzer Research Advisors Dr. Howard
Brooks Malinda Mann
Flight Summary Launch The roof of Julian Science
Center Launch Time 1415 Ascent Rate 1,200
ft/min. Burst 90,000 ft over Morgantown,
IN Burst Time 1526 Descent Rate 2,500
ft/min. Landing Time 1602 Landing Point
Southwest of Columbus, IN Conclusion The
balloon fill and release went smoothly and the
system followed the predicted flight line. The
faster than predicted ascent rate allowed us to
recover our experiments before we reached the
hilly, tree-covered terrain of southeastern
Indiana and Kentucky. We were able to track the
system with the onboard radio and used a handheld
Global Positioning System to walk to the exact
location of the landing. The solar cell
experiment provided us with data that supports
the theory that solar panels work more
efficiently the colder they are. In fact, they
gave out enough energy that each pod could
successfully power itself with solar energy,
instead of batteries, which we used. This
technology will be used in the replacement of
cell phone towers by float balloons, which are
balloons that stay at a level in the atmosphere
for a long amount of time. These balloons will be
better than cell phone towers because the range
is greater, for example, one balloon would cover
Indiana, while it takes many towers. Also, it
would give better coverage because you dont have
to worry about physical obstacles such as hills
and valleys hindering your cell phone reception.
Our data shows that during the middle of the
day that the sky is more polarized horizontally,
which is expected. The unusual thing is that it
shows that it was more polarized horizontally
throughout the entire flight. It is expected that
after a certain level of the atmosphere that the
amount of horizontally and vertically polarized
light is equal, but this was not the case. The
reason that we expected the amount of
horizontally polarized light to be greater is
because, typically, in the middle of the day the
light is horizontally polarized, and at sunrise
and sunset the amount of vertically polarized
light is greater. Overall, we had a pretty
good flight. We collected the data that we
needed, and even finished ahead of schedule. It
was a good learning experience and we even had
fun doing it.
Background The Balloon Assisted
Stratospheric Experiments (BASE) project is a
program that uses helium-filled weather balloons
to carry scientific experiments to the
stratosphere. It is operated and controlled by
the Physics and Astronomy Department at DePauw
University. The scientific experiments that are
sent up are designed by DePauw students and High
School students from schools like Cloverdale.
We used things such as a digital compass,
phototransistors, solar panels and a circuit
board. We connected the compass and the solar
panels through the circuit board by using wires
that connected to the solar panels and the
compass to 9V battery to power it up.
As we helped to inflate the latex balloon we were
required to wear latex gloves to keep from
damaging the balloon, which wasnt very pleasant
on a hot day.
This is the one of the pods that we sent over
90,000 ft in the atmosphere. There were four
pods that all held different experiments. Which
also make lovely purses.
Kayleigh is helping tie off the balloon with zip
ties. After cutting the wrong string, Dr. Brooks
decided to change the color of the string.
The other B.A.S.E. sent up a pod with ours that
measured the muons in the atmosphere.
Analysis Solar Panel Output- This shows the
average minimum and the maximum voltage of all
four solar cells. There is an increase in
voltage until time 1452 where there is a small
decrease up until the time of the balloon
bursting. After the balloon burst at 1526, the
voltage output shows a similar pattern except in
a condensed version because the pods are
descending at a faster rate than they were
ascending,
Procedure The preparation for the pod in
our experiment was completed during the first two
days. The pod included solar panels, binary
compasses, and photo transistors. After creating
the proper circuits on the solar panels we had to
test them outside before we were able to send
them up in the balloon. They were sent up on the
side of the pod to determine the light intensity
of the sun at the different altitudes.
The binary compass was the next thing that we
worked on. We had to confirm the binary output
matched the direction by testing the compass and
its readings in relation to the correct
directions. The binary (brad) system is a system
used by people to change 360 of a compass
reading into a binary system of 256 divisions.
(Shown below) We used this to designate the
compass directions into numbers that the digital
compass can compute. The compass was used to
determine where the solar panels and photo
transistors were facing in relation to the sun.
The system is used in brads by the program which
is a series of ones and zeros and are then added
together to determine where the pod was facing.
After the solar panels and the binary
compass we connected the solar panels to a ground
wire and connected two resistors to each wire (as
shown below). The resistors attached to the
solar panels were to restrict the output to a
smaller reading that the command pod could
measure. Our final step in preparation was to
calibrate the photo transistors. We placed
Polaroid filters on the two outside transistors
and left the one in the center uncovered. The
purpose of the Polaroid filter was to help
determine the polarity of sunlight.
In the last few minutes of our launch our pod
needed zip ties to make sure everything was
secure.
These are the photo transistors that measured
the polarity of the light from the sun.
Thank goodness it landed in the tree and not in
he field two feet away.
Finishing up the final touches on the pods, to
make sure they will last though the decent.
The two lines in this graph are plots of
horizontal and vertical polarizations in ratio to
un-polarized light. Throughout the whole flight
the photo-transistor with horizontal polarization
was more efficient which was different than what
we had predicted. We anticipated both signals
being the same at the higher altitudes. After
burst the data is scrambled because the pod was
tumbling.
Just after launch on the rooftop.
B.A.S.E. Team
Acknowledgments Supported by the Lilly Endowment
Inc. Grant 20041561000. We would like to thank
Dr. Howard Brooks, Jessica and Allyson for
directing our B.A.S.E. (balloons) research. We
appreciate the support of Toni Tomlinson,
Michael Nees, Malinda Mann, The Knoy Resource
Center, and also Dr. Milner for allowing us to
use the bus. We also thank DePauw University for
hosting us.
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