LSU 10/27/09 Student Payload Experiments 1

Student Payload Choices2009 - 2010

Ballooning Unit, Lecture 7

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Balloon Payload Requirements• Limited to about 500 grams weight• Roughly a polygonal prism with 15 cm to 20 cm long sides• Mechanical structure constructed from ¾” polystyrene foam• Vehicle interface is a pair of strings, separated by ~17 cm, that pass through

the payload unbroken and secured with spring clips.

Payload mechanical interface

• Need to conduct some kind of science or technology experiment

• Designed, built, tested and shown to be fully “space worthy” by May 2010.

– You will need to successfully complete three major reviews of your progress.

• 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.

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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 – Either previously developed and flown or – Should be feasible to develop and fly within the limitations of this

program– Your team needs to choose one of these payloads to work on!

• Your team will have one month to develop your Pre-PDR– Research and write the scientific background for your payload– Determine your mission goals, objectives and requirements– Establish a general schedule for payload development

• Pre-PDR document is due November 25, 2009• Pre-PDR oral presentation is due December 1, 2009

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Payload Choices for 2009-2010

1. Temperature, pressure, humidity and imaging characteristics of the atmosphere structure – One team must do this one

2. Radiation Intensity as a function of altitude• Coordinate observations with payload topic 3

3. Electrical conductivity of the atmosphere as a function of altitude• Coordinate observations with payload topic 2

4. Measure intensity of UV bands as function of altitude to deduce properties of ozone layer – Related to 5

• Coordinate observations with payload topic 55. Directly measure concentration of ozone and NOx gases as a function of

altitude using solid state ITO sensor – Related to 4• Coordinate observations with payload topic 4

6. Investigate thermal flow and conductivity of boundary layer around payload7. Investigate methods to optimize atmospheric temperature measurements8. Develop an inertial sensing system which will provide sub-minute of arc

orientation knowledge

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1. Characteristics of the Atmosphere• 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 atmosphere.

• Pressure decreases in an exponential manner

• This payload would implement temperature, pressure and humidity sensors to measure this variation.

• Need to understand sensor & ADC range & accuracy.

• Compare with standard atmosphere model

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1. Characteristics of the Atmosphere

• Payload would fly a digital video camera and be automatically controlled to take a series of video segments

• 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• Meeting the power and weight constraints will be a challenge

• Provide high definition video of ground or Earth limb from low to high altitude

• Coupled with the temperature, pressure and humidity sensors this payload provides basic information about the flight

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2. Radiation Intensity vs Altitude• Cosmic rays are high energy nuclei

that originate outside our solar system.

• CR interact in Earth’s atmosphere producing a shower of particles

• The intensity of this radiation varies with altitude

• This payload would determine the radiation flux as a function of altitude on ascent and descent

• Two sensors to implement and compare– Geiger-Muller tube – Scintillator and solid state PM

• Coordinate observations with atmosphere conductivity payload

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3. Conductivity of Atmosphere

• Investigate the ion content of the atmosphere as a function of altitude– Provides fundamental knowledge of the Earth electrical field– Is the level of ionization related to cosmic ray interactions?– How to clouds affect the field?– Connection to Sprites, ELVES, TGF???

• Use a pair of cylindrical capacitors to measure positive and negative charges

• Potentially very sensitive to noise– Need very careful design work and calibrations

• Coordinate observations with radiation investigation

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4. Intensity of UV versus Altitude

• 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 Sun.

• 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

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5. Direct Measurement of Ozone

• Use solid state ITO sensor to directly measure Ozone and NOx concentration

– Sensor changes resistance in proportion to the gas concentration

• Collaborate with the University of North Florida to obtain the sensors

• Need to keep sensor at ~ constant temperature• Need to develop interface electronics and software• Coordinate with payload topic 4

HASP 2008 Flight Result

Expected Ozone Concentration

Single ITO Sensor

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6. & 7. Thermal Investigations

6. Investigate thermal flow & conductivity of boundary layer around payload• Temperature sensors on box interior, interior surface, exterior

surface, 5 cm boom and 10 cm boom• Determine heat flow and the payload effect on measuring the

temperature of the atmosphere.

7. Optimizing thermal shields for temperature sensors• Temperature sensors on 10 cm booms with white, black,

checkered and silver shields• Measure and model the “atmospheric temperature” measured

by the four sensors

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8. Minute of Arc Inertial System

• Develop an inertial attitude sensing system that would be accurate to less than one minute of arc

• Use to investigate the rotation and turbulence of the payload during flight

• Use some combination of magnetometer compass, tilt sensors, fiber-optic gyroscopes, accelerometers and a sun sensor

• Develop system that would determine payload attitude to about one arc-minute

• Correlate observed turbulence with atmosphere layers

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Deadline!

• By 5 p.m. Tuesday November 3 e-mail to me your first & second payload choices.

• Include the following in the body of your e-mail– Your name– Your team designator– First priority payload type (i.e. from slide 4 here)– Second priority payload type– The kind of role (e.g. software, electronics, design,

management) you see for yourself on the payload team

guzik@phunds.phys.lsu.edu