Alex Ngure, Casey Sutherland, Nate Warner, Tad Nielsen

AEM 1905 - November 23, 2010

Mission Overview

• Measure temperature, pressure and relative humidity throughout the flight.

• Examine rate of change in darkness of sky as altitude increases.

• Attempt to confirm the Ideal Gas Law.• We expect:

•Constant increase in darkness•Ideal Gas Law holds true

Design Overview

Flip Video Camera to film balloon for volume and color strip/sky for percent darkness data.

Balloon Sat Easy flight computer, programmed to take temp., pressure, and rel. hum. data every 0.25 minutes.

Weather station to measure temperature, pressure, and relative humidity.

Heater to keep components inside payload warm.

Zigbee radio for sending data from one weather station to the ground.

Latex balloon to monitor for Ideal Gas Law experiment.

HeaterKeeps everything

from freezing

Battery Pack

Battery

Battery

Battery

HOBOCollects

temperature data

ZigbeeSends data to the

ground

Weather StationCollects temperature, pressure, and relative

humidity data

Weather StationCollects temperature, pressure, and relative

humidity data

CameraMonitors volume

of balloon and color of sky

Battery

Interface board

Interface board

Pre-Flight Testing

• Flight computer and weather station:• Tested by Philip: minor errors to fix in lab.

• Camera: turns on, takes video, red light.• Cold soak test: HOBO works, heater works.

Pre-Flight Testing• Payload structural strength.

• Tubing/rigging yank test.

Pre-Flight Testing

• Camera: film inflating balloon in the lab.• Boom strength: hang payload from ceiling.

• Needed to attach a string from end of boom to payload above.

• Tests we didn’t perform:

Expected Science Results

http://www.aerospaceweb.org/question/atmosphere/atmosphere/layers.gif

360900 ft

295300 ft

229700 ft

164000 ft

98400 ft

32800 ft

-148*F 32*F 140*F

Expected Science Results

http://www.sas.org/tcs/weeklyIssues_2007/2007-12-07/project1/images/Project_1_Fig_6_Dec_2007_relativehumidity.jpg

Expected Science Results

• Ideal Gas Law:• PV = nrT• Expect it to be confirmed.• As pressure and temperature decrease with

altitude, volume will increase.

• Darkness of Sky:• Couldn’t find anything published online.• Expect a constant increase in darkness at altitude

increased, but this is only a guess.

Flight Day – Gopher Launch 33• Started at Akerman Hall around 6:30 am.

• Alex went MIA, left around 7:00 am.

• Drove to Pierz, MN, launched at 10:04 am.• Attempted to drive along with balloon:

• Detoured through Mille Lacs County.• Crossed the St. Croix river on Highway 8.• Continued to Barron, WI.

• Lunch in Barron, WI.• Balloon landed near Lake Holcombe, WI,

retrieved by Philip.

Flight Day – Gopher Launch 33

Flight Day – Gopher Launch 33

Flight Day – Gopher Launch 33• Payloads landed in a tree.• When our payload landed:

• Zigbee still transmitting data.• HOBO still collecting data.• Camera had run out of memory, but still functional.• Boom was still attached and unbroken.• Balloon was still unpopped.

• It had a tiny hole and had been leaking.

• The boom was snapped while getting the payload out of the tree.

Science Results – Path and Altitude

• Launch: Pierz, MN• Land: Lake Holcombe, WI• Maximum recorded altitude: 90,694 feet• Flight time: 145.5 minutes

Data Calibration

• Raw data is given as numbers that don’t represent the data you want.

• We then are given an equation to convert raw data into usable data ((((((+B8/1024)*5)*100)-273)+40)*1.8)-40 (temp F)

• ((((+D8/1024)*5)-0.5)/4)*1013 • Pressure in millibar

Science Results – Temp. and Rel. Hum.• Temperature constant for

over 10,000 ft. (unusual?)• Drops to nearly -50*F near

50,000 feet.• Rises back to -25*F near

75,000 feet.

• Relative humidity spike near 30,000 feet.

• “High clouds” are found near 30,000 feet.

Science Results - Pressure• Pressure greater

inside balloon, but same general shape.

• After burst, “inside balloon” doesn’t exist, data nearly identical.

• “External” comes from Team Hindenburg.

Science Results – Darkness of Sky

• Compared color of sky to colors on color scale.• Looked at pictures, assigned a numerical (percent

black) value at each time examined.• Converted time to altitude using equations

0 10 20 30 40 50 60 70 80 90 100

given by Dr. Flaten.• Plotted altitude vs.

percent black of sky.• Added a trendline to

help offset error.

Science Results – Darkness of Sky

• Fairly linear = constant increase.

• 100% around 85,000 feet.

• 1.12% darker every 1,000 foot increase.

Science Results – Ideal Gas Law

• Had planned on being able to observe balloon in our own video. Had video taken in the lab of inflating balloon to compare to.

• Video didn’t work, needed to convert to use Team Hindenburg video.

12 real inches 14.4 screen mm

Science Results – Ideal Gas Law

• Used diameter measurements to calculate volume, converted to L.

• Had pressure in mb and temperature in *F from weather station.

• Converted pressure to atm, temperature to K.• PV = nRT, n and R are constants, so PV/T should

be constant.• Graphed PV/T vs. time, included a trendline.

Science Results – Ideal Gas Law

PV / T is constant, Ideal Gas Law holds

Conclusions/Lessons Learned

• Darkness of sky increased with altitude.• Increase was linear, and on our scale, increase

was 1.12% per 1,000 feet.• Around 80,000 feet, sky was 100% dark.

• Using a balloon, and its pressure, volume and temperature data, Ideal Gas Law confirmed.

Conclusions/Lessons Learned

• Problems with Ideal Gas Law experiment:• Balloon didn’t pop in GopherLaunch 33.• Balloon/boom tipped over in both GL33 and

GL34D.• Zigbee data didn’t transmit to the ground

• Boom could be redesigned to prevent tipping.• Need to find a better way to attach balloon.

• Boom could be put on top so that balloon hangs down into camera view.

• Other possible experiments.

Words of Wisdom• Stay on top of assignments, they can pile up very

quickly.• You will succeed in this class if you stay organized and

communicate with your group.• Group meetings are important, show up.• Be sure you test every aspect of your payload,

especially the things that you think couldn’t go wrong.• It’s easier if all of your components can fit inside your

box.• Don’t bring pancakes on the balloon chase; have a

muffin, have some fruit, have some cereal, have a NutriGrain bar… anything but pancakes!

Acknowledgements

• Dr. Flaten for answering our questions and helping with data collection and analysis.

• Cait, Seth, Kyle, Joey and Philip for helping us in the lab and with testing our components.

• Team Hindenburg for allowing us to use their video and external weather station data from Gopher Launch 34D.