TEAM JUPITER
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TEAM JUPITER. KATHERINE BLACKBURN· SETH BURLEIGH · JOSEPH TRAN. LaAces 2009-2010 Pre-Preliminary Design Review. MISSION GOAL.

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TEAM JUPITER

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Team jupiter

TEAM JUPITER

KATHERINE BLACKBURN· SETH BURLEIGH · JOSEPH TRAN

LaAces 2009-2010

Pre-Preliminary Design Review


Team jupiter

MISSION GOAL

Our goal is to investigate the causes of atmospheric electrical conductivity as a function of altitude. The launch will take place at the Columbia Scientific Balloon Facility (CSBF), in Palestine, Texas on May 25, 2010.


Team jupiter

DEFINITIONS

  • Alpha Particles-ionizing forms of particle radiation

  • Aerosols-Small particles made up of atoms which

  • cling to nuclei in the atmosphere

  • Cosmic Ray-rays of highly energized particles from space

  • Humidity-Clouds, haze or other moisture collection in the atmosphere

  • Laminar Flow-flow of particles in a uniform direction

  • Shot Noise-Noise in the voltage measurement due to ions directly striking the inner electrode


Team jupiter

SCIENCE GOALS

  • See if there exists any correlations between air conductivity and cosmic ray activity

  • Show uncharacteristic fluctuations in conductivity due to meteorological

  • events

  • Compare general profiles of temperature, pressure, humidity, and altitude with conductivity


Team jupiter

SCIENCE BACKGROUND

  • WHAT IS ATMOSPHERIC ELECTRICAL CONDUCTIVITY?

  • The measure of

  • positive and

  • negative ions in

  • the atmosphere

  • Generally increases

  • with altitude

Figure 1- Altitude as a function of conductivity. Most of the potential drop of the atmosphere occurs near the surface. Adapted from Reference 2.


Team jupiter

SCIENCE BACKGROUND

  • WHAT AFFECTS ATMOSPHERIC ELECTRICAL CONDUCTIVITY?

  • Pollution level of air (e.g. aerosols)

  • Increased radiation in an area (e.g. cosmic

  • rays on the atmosphere)

  • Wind, pressure, moisture, and humidity

  • (i.e. factors that affect ion mobility)

  • IMPLICATIONS?

  • Cloud formations

  • Thunderstorms


Team jupiter

SCIENCE BACKGROUND

  • PAST PROJECTS

  • Pollution measurements

  • based on surface

  • conductivity in

  • Mysore, India

  • Balloon payload in

  • Antarctica (Figure 2)

Figure 2 – There is a quasi-sinusoidal behavior of the electrical field with respect to time as shown above. Adapted from Reference 2.


Team jupiter

SCIENCE REQUIREMENTS

  • Must be able to sense small changes to see

  • uncharacteristic changes from surface to

  • 100,000 feet

  • Altitude and time must be measured

  • Cosmic ray intensity and atmospheric

  • conductivity data needs to be compared

  • for possible correlations


Team jupiter

TECHNICAL GOALS

  • Measurement will occur from surface level to 100,000 feet

  • Target ascent rate is 1000 feet per minute

  • Altitude, temperature, cosmic ray count, windspeed, and humidity will need to be measured


Team jupiter

TECHNICAL BACKGROUND

THEORY OF OPERATION: VOLTAGE DECAY

  • Sample 1-2 Hz for 5-20 seconds

  • Reset Voltage


Team jupiter

TECHNICAL BACKGROUND

Equation 3 – Conductivity vs. exponential fit time constant

Equation 4 – Capacitor current vs. combined Gerdien and measurement capacitance and change in outer-inner cylinder voltage

Equation 5 – Conductivity

Equation 6 – Theoretical cylindrical capacitor capacitance

Equation - Gerdien capacitor current given V (outer voltage- inner voltage), L (length), a (conductivity), b(inner radius), and a (outer radius)

Equation - Critical mobility - the minimum ion mobility (drift velocity/electric field) that will be captured by the gerdien capacitor


Team jupiter

TECHNICAL BACKGROUND

CRITICAL MOBILITY,

ION CURRENT, BIAS VOLTAGE


Team jupiter

TECHNICAL REQUIREMENTS

  • A voltage-sampling rate of 1 hertz (Hz) per 10 seconds (s)

  • Memory of 4050 bytes

  • At lower conductance (around 100 femtoSiemens) a 12 bit analog to digital converter with a 5 voltage (V)

  • The end of the inner electrode must be bullet shaped to promote laminar flow


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ROLES AND STAFFING PLAN


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REFERENCES (1/2)

K. Nagaraja, B.S.N. Prasad, N. Srinivas, M.S. Madhava, Electrical conductivity near the Earth's surface: Ion-aerosol model, Journal of Atmospheric and Solar-Terrestrial Physics, Volume 68, Issue 7, April 2006, Pages 757-768, (http://www.sciencedirect.com/science/ article/ B6VHB-4JDMR5M-1/2/607a27d56c6adbf8ce265ea1ad0d8e0a)

E.A. Bering, A.A. Few, J.R. Benbrook, The Global electric circuit, Journal of Physics Today, Volume 51, Issue 10, 1998, Pages 24-30

N. Ragini, T.S. Shashikumar, M.S. Chandrashekara, J. Sannappa, L. Paramesh, Temporal and vertical variations of atmospheric electrical conductivity related to radon and its progeny concentrations at Mysore, Indian Journal of Radio & Space Physics, Volume 37, August 2008, Pages 264-271

K.L. Aplin, A novel technique to determine atmospheric ion mobility spectra, Journal of Atmospheric and Oceanic Physics, January 2005, (arXiv:physics/0501129v1)

K.L. Aplin, Instrumentation for atmospheric ion measurements, University of Reading Department of Meteorology, August 2000, Pages 1-274


Team jupiter

REFERENCES (2/2)

J.P. Scott and W.H. Evans, The electrical conductivity of clouds, Journal of Pure and Applied Geophysics, Volume 75, Issue 1, December 1969, Pages 219-232 (http://www.springerlink.com/content/x804k7123mqhn3r5/)

R.G. Harrison, A.J. Bennett, Cosmic ray and air conductivity profiles retrieved from early twentieth century balloon soundings of the lower troposphere, Journal of Atmospheric and Solar-Terrestrial Physics, Volume 69, November 2006, Pages 515-527

K.A. Nicholl, R.G. Harrison, A double gerdien instrument for simultaneous bipolar air conductivity measurements on balloon platforms, Journal of Review of Scientific Instruments, Volume 79, August 2008

K.L. Aplin, R.G. Harrison, A computer-controlled gerdien atmospheric ion counter, Journal of Review of Scientific Instruments, Volume 71, Issue 8, August 2000

B. Balsey, (2009). Aerosol size distribution . Retrieved from http://cires.colorado.edu/science/groups/balsley/research/aerosol-distn.html


Team jupiter

QUESTIONS?


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