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Student Payload Choices


Mechanical structure constructed from foam core board ... Telemeter video signal down to ground? LSU 09/06/05. Student Payload Experiments. 18 ... – PowerPoint PPT presentation

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Title: Student Payload Choices

Student Payload Choices
  • Ballooning Unit, Lecture 7

Your balloon payload
  • Limited to about 500 grams weight
  • Roughly a cube with 15 cm to 20 cm long sides
  • Mechanical structure constructed from foam core
  • Vehicle interface is a pair of strings, separated
    by 17 cm, that pass through the payload unbroken
    and secured with spring clips.
  • Need to conduct some kind of science or
    technology experiment
  • Designed, built, tested and shown to be fully
    space worthy by May of next year.
  • Will have about 14 weeks to complete this phase.
  • 48 hours after launch you will need to have
    calibrated science results from your flight and
    present your results to an audience of
    professional scientists and engineers.

Payload mechanical interface
Need to begin thinking now!
  • Given the constraints, you need to think about
    and address issues throughout the academic year
  • Here we discuss some example payloads that have
    either been previously developed and flown or
    which should be feasible to develop and fly
    within the limitations of this program
  • You need to choose one of these payloads to work
  • During the current skill building phase then
  • Research the scientific background for your
  • Think about how a particular activity / concept
    applies to your payload (I guarantee that they
    ALL apply) and keep track of these in a payload
    design notebook
  • Determine who in your group has similar interest
    or complimentary skills and begin developing a
  • Develop hardware / software prototypes as an
    activity extension

Potential Payload Topics
  • Look up experiments
  • Cosmic ray intensity
  • Cosmic ray components
  • UV transmission through atmosphere
  • IR emission
  • In-situ experiments
  • Atmosphere temperature, pressure profile
  • Atmosphere ozone profile
  • Atmosphere humidity profile
  • Atmosphere trace gas profile (more difficult)
  • Remote sensing experiments
  • Imaging the ground and/or limb
  • Multispectral (filtered) imaging of the ground
  • Technology experiments
  • Balloon payload dynamics
  • Solar cell efficiency
  • Video camera imaging (live or recorded)

Cosmic Ray Intensity
  • Cosmic rays are high energy nuclei that originate
    outside our solar system.
  • CR interact in Earths atmosphere producing a
    shower of particles
  • The intensity of this radiation varies with
  • This payload would determine the radiation flux
    as a function of altitude on ascent and descent
  • Simple to implement detector system by using a
    hand-held radiation monitor
  • Most effort will be in understanding what flux
    is and doing the appropriate calibrations to
    convert your measurement to flux.

Cosmic Ray Components
  • Cosmic rays include electrons, protons, heavy
    nuclei (He to beyond Iron) plus interaction
    products such as neutrons, pions, muons, etc.
  • This payload would try to measure the relative
    abundances of some of these components.
  • Use multiple detector systems with different
  • Geiger-Muller tube for electrons, protons
  • Plastic scintillator with a photodiode for higher
    energy deposits produced by heavy ions
  • To compare multiple detector system it will be
    critical that you can determine the correct
    flux for each detector.

Transmission through atmosphere
UV Transmission
  • UV is absorbed by ozone in the upper atmosphere
  • Payload would measure the UV intensity as a
    function of altitude and infer the vertical
    distribution of ozone
  • One or more sensors (or the appropriate
    wavelength sensitivity) would monitor UV from the
  • The signal from the sensor would need to be
    conditioned and converted to a digital number by
    an ADC
  • You will need to take into account rotation of
    the balloon craft
  • Calibrations of sensor and ADC will be needed to
    determine flux

Infrared Emission
  • Sun energy is absorbed by objects on Earth
    (ground, clouds, atmosphere) and emitted in the
    infrared wavelengths (8 15 microns), further
    astronomical objects, such as the Sun, emit
    infrared energy.
  • This payload would implement an infrared sensor
    to measure the temperature of some particular
  • The signal from the sensor will need to be
    conditioned and converted to a digital number by
    an ADC.
  • You will need to take into account rotation of
    the ballooncraft.
  • You may also need to account for temperature
    dependences in your sensor and/or electronics.
  • The trick here is to understand what your sensor
    is looking at and to have the calibrations
    necessary to convert your measurement to a

Atmospheric Structure
Typical max balloon altitude 30 km
Temperature, Pressure Profile
  • The temperature and pressure of the atmosphere
    varies as a function of altitude.
  • Temperature initially decreases with increasing
    altitude, then increases as UV is absorbed in the
  • Pressure decreases in an exponential manner
  • This payload would implement temperature and
    pressure sensors to measure this variation.
  • Need to understand sensor ADC range accuracy.
  • Compare with standard atmosphere model

The Distribution of Ozone
  • The ozone layer, located between 15 50 km
    altitude, shields the Earth from high frequency
    UV components by absorbing this radiation.
  • Payload would use a standard electrochemical
    concentration cell (ECC) to measure the ozone
    density as a function of altitude
  • Will also need to measure temp. and pressure
  • ECC is based upon an iodide iodine redox
    reaction using a potassium iodide solution, so
    you will need to keep your sensor from freezing.
  • Calibration of your sensor is essential
  • This is a more challenging experiment, but doable.

Absolute Humidity
  • The amount of water vapor in the stratosphere may
    be directly dependent upon interactions between
    ozone, UV and methane. There are few in-situ
    studies of humidity at high altitude and a poor
    understanding of the mechanisms that control it.
  • Payload would include humidity and temperature
    sensors to obtain the absolute concentration of
    water vapor as a function of altitude
  • May also want auxiliary measurements to look for
    possible causal relationships.
  • Include UV and/or methane sensor
  • Collaborate with another team doing UV or methane
  • Will need to condition sensor signals and use an
    ADC to obtain digital information
  • Will need to understand sensor / ADC range and

Trace gas profiles
  • There are many other components in the atmosphere
    that could be interesting to measure as a
    function of altitude
  • Methane, Carbon Dioxide, Chlorofluorocarbon
  • Requires an appropriate sensor that could fit
    within the balloon payload power, size and weight
  • Likely to be temperature dependent, so will need
    to monitor temperature and calibrate sensor for
    flight conditions.
  • May need to monitor pressure to obtain absolute
  • Could collaborate with multiple teams, each
    measuring a single component.
  • This would be a challenging payload

High Altitude Imaging
  • Provide aerial view of ground or Earth limb from
    low to high altitude
  • ACES program has yet to achieve high quality
    images from high altitude
  • Payload would fly a digital camera and be
    automatically controlled to take a series of
  • May need to include a polarizing filter to cut
    down on glare
  • Need to record images on non-volatile media to
    avoid loss during power off
  • Will need thermal-vacuum testing to assure system
    will function correctly.

Multi-spectral Imaging
  • Remote sensing images taken of the same area but
    in different frequency bands can be used to
    distinguish between healthy vegetation, water
    features, surface roughness and other
  • Payload would include multiple cameras each of
    which would take a image through a different
    color filter. (e.g. IR, green, UV)
  • Alternate payload would have one camera and a
    wheel that would include multiple filters.
    Software would then rotate the wheel one
    increment prior to taking the image
  • Camera will need different exposure times
    depending upon which filter is used.
  • This will be a very interesting and challenging

Technical Payloads
  • Measure the dynamics of the payload through use
    of accelerometers and/or tiltmeters.
  • Form basis of an inertial position sensing system
  • Investigate use of balloon payload for ?g
  • Measure the efficiency of various solar cells
  • Can balloon payloads be powered by solar cells?
  • Record voltage and current for each cell
  • Develop a compact video camera payload and record
    specific events during the flight
  • Main problem here is weight
  • Telemeter video signal down to ground?

Your Own Idea
  • You can also develop an alternative payload based
    upon your own idea.
  • However, keep in mind that your payload must have
    a relevant science / technical goal and must be
    feasible given the payload weight, power, budget
    and time constraints.
  • The payloads identified here can be developed so
    they fit within these constraints.
  • In any event you need to begin your payload
    planning now!