Our data came from our flight computer and was recorded in a .TXT file. The column headings include:
Date, Time, Latitude, Longitude, Head, Km/h, Alt-m, mV, mA, mW, Temp C, and Pa
We then imported the .TXT file into Microsoft Excel and deleted all the information from before the launch and after the landing. Then Dad imported the Excel file into Tableau, a graphing software program. We then came up with a bunch of different graphs to display our data.
Click images to enlarge.
Altitude vs Pressure
As the balloon ascends, the pressure decreases because the density of air goes down. As our spacecraft approaches 30,000 meters above sea level, the atmospheric pressure approaches zero pascals. This lack of pressure is what eventually causes the balloon to pop.
Altitude vs Temperature
We learned about the changes in temperature shown in this graph in our last launch, which is very similar to this graph, which is good, since we don’t think the layers of the atmosphere have changed since our last launch.
The first layer of the atmosphere is the troposphere. While traveling upward through the troposphere, the temperature gets colder. But as soon as it reaches the second layer of the atmosphere, the stratosphere, the temperature becomes warmer. We will have to do some more research to find out why.
Altitude vs Current
We attached a solar panel to our spacecraft and it measured the solar current that it was collecting. This graph shows the current that the solar panel absorbed from the sun. The lines are very jagged because of the motion of the spacecraft, but the trend line we created shows very clearly that our hypothesis was correct: As we get higher, there is more current generated by our solar panels and we think that this is because there are less particles in the air to block the suns rays.
Altitude vs. Power
Power is equal to Voltage times Current (Power = VI) so both voltage and current are factors in this graph. You can see the lines gradually show the curve that the voltage showed during the ascent. Also, the trend line, though it is not quite as pronounced, shows that there was more power as the balloon ascended, which shows the current.
Altitude vs. Voltage
The voltage measurement is measuring the voltage produced by the batteries powering our flight computer. We were very surprised at the change in voltage because we thought that the battery voltage would continually stay the same and not change. It did not seem that we could make any conclusions from this chart. But by comparing voltage to a different measurement in our next chart was really interesting.
Voltage vs. Temperature
When we first saw this graph we thought that since the temperature was changing with the atmospheric layers, the voltage levels must be too. However, we did some more research and we found out that the voltage levels actually changed because of the temperature levels, not because of the atmosphere. The temperature changes because of the atmosphere, and the voltage changes because of the temperature.
We did some more research and the reason this happens is because of the chemical reactions inside the battery. When the temperature gets warmer, the chemical reactions happen faster, and consequently there is higher battery performance and more voltage. On the flip side, when the temperature gets colder, the chemical reactions happen slower, so there is lower battery performance and less voltage. This correlates very clearly with our data set from the launch.
Altitude vs Speed
Our speed data was a little bit different from the last launch: see From the Project Binder. Last launch, our speed stayed around 35 km/h until it reached the tropopause, the space in between the troposphere and the stratosphere, the first and second layers of the atmosphere. In the tropopause, there is very little air resistance so the spacecraft was able to move much quicker than otherwise. However, in our second launch our spacecraft’s speed rose steadily to reach its high speed in the tropopause instead of a sharp difference of speed like our first launch.