1. LaACES High Altitude Ballooning Atmospheric Density By: Henry Hardee Sina Zarei Ian Walsdorf

2. To determine the density of the atmosphere throughout the flight using the P and T that we find assuming air is an ideal gas. To better understand the effects that freezing temperatures and low pressures can have on equipment through the atmosphere. To learn about circuits and electronics and attempt a hands on experiment.

3. Atmospheric pressure reduces with altitude: -Due to gravity -The gravitational attraction between the earth and air molecules is greater for those molecules nearer to earth than those further away -Molecules further away from the earth have less weight but they are also 'standing' on the molecules below them, causing compression http://www.npl.co.uk/pressure/faqs/atmosaltitude.html

4. Simple density formula Boyle’s Law R - is the universal gas constant - we used 0.000082057 m^3/atm*K m - is the molar mass (in our we use air) kg P – pressure atm T – temperature K ρ – density kg/m^3 ρ (rho) - is the density of the substance, measured in kg m^3 m - is the mass of the substance, measured in kg V - is the volume of the substance, measured in m^3

5. We are using the DS1621+ND temperature sensor.

6. We are using the same pressure sensor that was used on the HASP project last summer. We did this for a few reasons the main one being that we are familiar with the part already. BASE -25°C SPAN -110°C Part # 442-1026-ND

8. Connections

14. Mechanical Design We choose to do a double box design instead of using the pink insulation foam we used thin foam board because rigidity and thermal characteristics. We used pink insulation and fiberglass insulation between the two boxes to further prevent heat escaping. We mounted our temperature sensor outside our inner box and exposed it to the atmosphere to get accurate readings. This design has so far been successful.

15. AUTOCAD DRAWINGS INNER BOX

16. AUTOCAD DRAWINGS BIG BOX

17. Weight Budget of the Pay Load: Weight limit: 500 g Balloon Sat W/ Sensors & Wires: ~82.40 g One 9 v Battery: ~46.6.0 g ~126.5g + 500 g - 329.9 g = 170.1g Outer Box ~74.4g Inner Box

18. Pressure Test Upon calibrating our pressure sensor we found to be a bias error of 2.05 psi. This is due to the fact that due to time constraints we were not able to reference our sensor to a 4 volt source so instead we referenced it to a 5 volt source. We put our payload in a pressure chamber and it showed a linear output.

19. Temperature Test We tested our payload by putting the box in an ice chest with dry ice for an hour. All of our components were fine when we pulled it out and our data sheet was correct

20. Impact Test The payload was dropped from a height of 10 feet to simulate the force felt upon landing this is because the nominal descent rate is approx. 20 feet/sec. We did this test 3 times and nothing was damaged in the process

21. Acknowledgements CSBF Dr. Guo Dr. Guzik Dr. Wefel Mr. Giammanco Mr. Ellison Jeff Kornuta NASA