BUSAT: Taylor Universitys Involvement

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BUSAT Taylor Universitys Involvement

• Presented by
• Zach Palmer
• David Patterson
• July 9, 2008

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About BUSAT

• Boston University Student satellite for
  Application and Training
• Competing in the USAF Nanosat 5 competition

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Stated Mission Overview
Perform measurements of the precipitating
energetic electron fluxes from low Earth orbit
over the high latitude auroral zones and to
simultaneously image the auroral emissions caused
by these electrons in order to better understand
the coupling between the Earths Magnetosphere
and Ionosphere (L0-1) and to construct a modular
subsystem bus design allowing for standardized
mechanical and electrical interfaces (L0-2)
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BUSAT mission, simplified

• To provide an opportunity for undergraduate
  research and design
• To collect important data useful for space
  weather forecasting

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Space weather
The magnetic field of the Earth protects us from
energetic charged particles emitted from the sun
during period of solar activity.
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Space weather
Below a view of the suns corona, taken during a
total solar eclipse
Above a view of an aurora, caused by collisions
of charged particles in the Earths upper
atmosphere
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Space weather
Below Particle populations in the inner
Magnetosphere (from NASA-RBSP website)
Above Large-scale magneto-spheric current
systems (from NCAR website)
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BUSAT Instrumentation
1. Auroral Imager A CCD camera-based system
that can image the aurora in multiple
wavelengths (L1-1) 2. Imaging Electron
Spectrometer a heritage instrument that
measures energetic electrons (30 keV to 500 keV)
and can resolve the particles pitch angle
(L1-2) 3. Langmuir Plasma Probe Measures low
energy, thermal electrons (0 to 6 eV) (L1-2) 4.
Very Low Frequency Receiver Integrates VLF
power in six separate frequency bands providing
knowledge of VLF waves (L1-3) 5. Magnetometer
The magnetometer is able to sample in three axes
(L1-4). Measures Birkeland currents.
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Taylors Responsibility for BUSAT

• Plasma Probe
• VLF Receiver
• Comm. System

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Comm. System (David Patterson)
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TUSat1 Satellite

• Project from 2001-02
• Prominently featured spherical Langmuir Plasma
  Probe

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Deus Ex Satellite

• 07-08 Eng. Phys. Senior Design Project
• Included both Plasma Probe and VLF Receiver
• Equipment being adapted for use with BUSAT

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Langmuir Plasma Probe

• Purpose Measures low energy, thermal electrons
  (0 to 6 eV) (L1-2)
• Explanation Will tell us the densities of
  electrons and ions along the path of the
  satellite, and information can also be used to
  find the electron temperatures.
• Original (Deus Ex) Design by Dan Brinks

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Theory of Operation

• Bias the probe to a given voltage relative to the
  surrounding plasma
• Measure the resulting current flowing from the
  plasma to the probe

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Expected Measurements Plasma Probe
Taken from Measurement Techniques in Space Plasmas
Taken from Satellite Observations of
Lightning-Induced Electron Precipitation
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Design Plasma Probe

• Measure electron densities ranging from 102 to
  108 e-/cm3
• Software programmable bias voltage ranging from
  -9V to 9V
• Logarithmic current amplifier using matched
  transistors (provides 6 orders of dynamic range)
• Temperature measurements of transistors for
  compensation
• 12 bit ADC
• Calibration circuitry
• Voltage sweep capable

Taken from Measurement Techniques in Space Plasmas
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LPP Software Block Diagram
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Collector/Boom Design Plasma Probe
For the LP to correctly gather data, it cannot be
within the Debye sheath. Hence, the deployment
length must be greater than the Debye length. In
the Ionosphere, the Debye length is roughly 1 cm.

• Design
• Spherical, aluminum collector
• Tri-axial cable
• Boom

Taken from Measurement Techniques in Space Plasmas
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Very Low Frequency Receiver

• Whistler waves - ducted EM plasma waves.
• Produced by
• lightning in the atmosphere
• magnetospheric processes
• Energize particles
• Particles enter loss cone
• precipitation (L0-1)
• Emissions and ionization (diffuse aurora)
• Important for M-I coupling (L0-1)

Whistler wave propagation (from
www.astronomie.be/radioastronomie/vlf.htm)
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Very Low Frequency Receiver

• Detect whistler waves
• Low pass front end
• Amplification
• Band-pass filters
• AC to DC Conversion
• Sample data
• Data transmission

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Status of VLF

• Indeterminate
• Possibility of handing project off to Jeff
  Dailey, a professional engineer out of Fort Wayne
• May need to be de-scoped entirely

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Original Plan
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Current Plan
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Benefits of splitting the projects up

• Lets me focus on getting one system board
  design operational, instead of three.
• Less chance of a system failure knocking out both
  systems.
• Ability to de-scope either project independently
  of the other one, based on progress.

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Rest of the summer

• Finish revised board design for the Langmuir
  Plasma Probe instrument
• Populate flight board
• TESTING DEBUGGING
• Balloon Flight Test (SuperLaunch)
• Coding

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Acknowledgements

• Dan Brinks Plasma Probe
• Jeff Moore VLF Receiver
• Jeff Dailey Comm System
• BU nanosatellite team
• Dr. Hank Voss
• Dr. Will Holmes
• Dr. Joel Gegner