( McNeese Everest Speed of Sound ) Columbia Scientific Balloon Facility Palestine,Tx May 2008

MESS GROUP 12/22/20152

3 Mission Operations The recorder and the player were turned on and data was stored in the memory of the recorder. All components were placed properly inside the box and sealed. The digital recorder actually began collecting data about 30 minutes before the launch. We used the voice command (launch!) to synchronize our data with the altitude information.

12/22/20154 The Payload (Heavy ~ 1 kg)

Side-view of the payload (light ~ 800 g) 12/22/20155

Up and away….. 12/22/20156 MESS

12/22/20157 Scientific Goals and Results The velocity of sound depends on several physical parameters that are both independent of chemical composition (like the temperature of the gas), density and bulk modulus of the medium, that are characteristic of the particular chemical composition of the medium. Consequently, the speed of sound could be used to determine (if environmental parameter like the temperature of the gas is known) the precise combination of individual gases present in the medium. (Information from Grambling would be nice). When we go home we will use methods to determine the chemical composition of the Earth‘s atmosphere even if it is a well known quantity. This is in the following of the spirit of the LA-ACES program that invited the students’ teams to pretend they are exploring the Earth as a space mission would when it explores another world. We plan to write article on this.

12/22/20158 We stopped recording here

Finally payload was found!!! 12/22/20159

10 Technical Goals and Results We measured the changes in the velocity of sound as a function of altitude and compared those changes with theory based on standard atmosphere model and ideal gas relationship between velocity and temperature. We recorded sound at a sampling rate of Hz. Our payload electronic equipment and box survived the low temperature and high altitude.

12/22/ Data Acquisition and Analysis The recorded data was extracted via USB into our computers. We had two channels representing the two microphones’ individual time series. Data was analyzed using MatLab codes. Environmental noise due to gusts of wind and motion of the box was filtered out digitally using band pass filter around signal frequency (1920 Hz). Remaining outliers were eliminated using a smoothing final filter applied to average value of the speed (averaged over 400 signal cycles).

12/22/ Velocity of Sound in the Atmosphere standard atmosphere theoretical result LA-ACES 9 MESS result

12/22/ Velocity of Sound in the Atmosphere Errorbars width equal to 1 sigma, 0.7 % of average value

MESS data is very close to standard atmosphere’s prediction (our is more realistic)

12/22/ Failure in data collection We failed to record the data of the full flight due to a mistake in selecting the correct recording memory. We used the built-in 2 GB memory of the recorder instead of the additional 4 GB memory card, which led to only 1.5 hrs of data recording.

Furthermore, we lost our second payload which confined our research to only data from the first payload. 12/22/201516

MESS success Although we got the data for only 1.5 hours, we completed 90% of our mission objectives. Our payload recorded the sound data of all three layers (troposphere, tropopause and stratosphere) and measured speed of sound with a precision of 2.7 m/s (0.7 % of the mean value of average measured speed at ground level) and also a high accuracy as compared with standard atmosphere. 12/22/201517

Can you hear the sound of a payload falling into the forest if nobody is around to listen? 12/22/ No, if you cannot find the payload.

12/22/ Special Thanks to... Other LA-ACES teams Dr. Santostasi Giovanni LA-ACES Organizers NASA Employees Don’t mess with MESS !!