LaACES High Altitude Ballooning

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LaACES High Altitude Ballooning

• Atmospheric Density
• By Henry Hardee
• Sina Zarei
• Ian Walsdorf

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PROJECT GOALS

• To determine the density of the atmosphere
  throughout the flight using the P and T that we
  find assuming air is an ideal gas.
• To better understand the effects that freezing
  temperatures and low pressures can have on
  equipment through the atmosphere.
• To learn about circuits and electronics and
  attempt a hands on experiment.

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Why pressure changes at different altitudes

• Atmospheric pressure reduces with altitude
• -Due to gravity
• -The gravitational attraction between the earth
  and air molecules is greater for those molecules
  nearer to earth than those further away
• -Molecules further away from the earth have
  less weight but they are also 'standing' on the
  molecules below them, causing compression

http//www.npl.co.uk/pressure/faqs/atmosaltitude.h
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Density
Simple density formula
? (rho) - is the density of the substance,
measured in kg m3 m - is the mass of the
substance, measured in kg V - is the volume of
the substance, measured in m3
Boyles Law
R - is the universal gas constant - we used
0.000082057 m3/atmK m - is the molar mass (in
our we use air) kg P pressure atm T
temperature K ? density kg/m3
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TEMPERATURE SENSOR

• We are using the DS1621ND temperature sensor.

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PRESSURE SENSOR

• We are using the same pressure sensor that was
  used on the HASP project last summer. We did this
  for a few reasons the main one being that we are
  familiar with the part already.
• BASE -25C SPAN -110C
• Part 442-1026-ND

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Data Acquisition
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Connections
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Altitude vs. Pressure
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Standard Values for Pressure and Temperature
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Our Expected Data
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PAYLOAD CONSTRUCTION
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Mechanical Design

• We choose to do a double box design instead of
  using the pink insulation foam we used thin foam
  board because rigidity and thermal
  characteristics.
• We used pink insulation and fiberglass insulation
  between the two boxes to further prevent heat
  escaping.
• We mounted our temperature sensor outside our
  inner box and exposed it to the atmosphere to get
  accurate readings.
• This design has so far been successful.

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AUTOCAD DRAWINGS
INNER BOX
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AUTOCAD DRAWINGS
BIG BOX
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Mechanical Design

• Weight Budget of the Pay Load

Weight limit
500 g

• Balloon Sat W/ Sensors Wires

82.40 g

• One 9 v Battery

46.6.0 g

• Outer Box

126.5g

• Inner Box

74.4g

500 g - 329.9 g 170.1g
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Pressure Test

• Upon calibrating our pressure sensor we found to
  be a bias error of 2.05 psi. This is due to the
  fact that due to time constraints we were not
  able to reference our sensor to a 4 volt source
  so instead we referenced it to a 5 volt source.
• We put our payload in a pressure chamber and it
  showed a linear output.

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Temperature Test

• We tested our payload by putting the box in an
  ice chest with dry ice for an hour.
• All of our components were fine when we pulled it
  out and our data sheet was correct

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Impact Test

• The payload was dropped from a height of 10 feet
  to simulate the force felt upon landing this is
  because the nominal descent rate is approx. 20
  feet/sec.
• We did this test 3 times and nothing was damaged
  in the process

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Acknowledgements

• CSBF
• Dr. Guo
• Dr. Guzik
• Dr. Wefel
• Mr. Giammanco
• Mr. Ellison
• Jeff Kornuta
• NASA