Materials
Many materials were required for this experiment to run smoothly. The weather balloon that carried the payload which was built with a variety of materials as well as multiple measuring instruments to collect and record data. The payload will be launched with one of two 3,000 gram latex, helium-filled balloons to reach the desired altitude. These weather balloons are designed to reach 30 km in altitude and can carry multiple payloads that will each weigh 1.5 kg. The payload most inner layer is a thick layer of lightweight foamcore which is the payload’s base (Figure 12). In the payload there will be a heating system comprised of six 9V batteries, six 1 kohm resistors, and coated wires. The mass of the heating system will be .4 kg. The heating system keeps the electrical components of the payload warm. At an altitude of 30 km, in the stratosphere, the temperature will be around -50 degrees Celsius. The batteries provide the heater with power to maintain a sufficient temperature in the payload. The Sparkfun Geiger counter measures many high energy particles, including muons. This will weigh .05 kg and is 4 by 2 in. The Geiger counter will be encased in a PVC pipe to provide electrical insulation to prevent coronal arcing, a payload-damaging phenomenon experienced by high voltage devices such as the Geiger counter (Figure 6). The BMP180 Pressure Sensor measures pressure and temperature, which can both be used to determine altitude. The sensor weighs .1 kg and is .5 by .5 in. The Arduino Uno is a microcontroller board that will have both of these instruments connected to it. It runs the data collection routine to record the signal produced by the Geiger counter and the sensor and stores it on a SD card. The arduino weighs .05 kg and is 3 by 2 in. Arduino is a scripting language that will take the information from the two systems and store the data on an SD card (Figure 8). The SD card will be in a Sparkfun MicroSD shield which will allow the data from the flight to be stored on the Arduino, giving it storage space and allowing the data to be manipulated and moved. The SD card will then be accessed after the flight so the data can be recorded and later interpreted after the payload is recovered.
Another defense against the harsh temperatures is the fiberglass insulation that lines the inside of the payload. The payload is also covered in aluminum foil to provide extra structural support and enhance the aesthetics of the payload. A space blanket is another layer of thermal insulation to keep the inside of the payload warm. The temperatures get really cold when the payload is thirty km up which is the reason the payload has so much insulation. Refer to Figure 13 to see the box which has completed layers, but lacks all its electrical components.
Methods
To get the payload in the air, it's much more than just launching the balloon with the payload attached. There is a lot of testing with either instruments or the payload itself before it can be launched. The center of gravity has to be in the center so the payload does not fall at an odd angle. This would interfere with the flight and landing and might damage the instruments. The heater has to be tested multiple times so it works properly. The heater has to produce enough electricity to power the payload for the entire three hour flight so the instruments can record data for entire duration. The heater must spread its use of electricity out over time so as not to use too much power too fast. The code for the arduino has to be written and must work correctly so the data can be accessed after the flight. TheGeiger counter must work correctly so the data is precise and reliable. The sensor must run smoothly and gather data precisely. After the instruments are all assumed to be working correctly, the box needs to be tested. The temperature can be tested by using liquid nitrogen, which has a temperature of -196 degrees Celsius. The payload can be submerged to see if the heater provides sufficient heat for the payload and all the other components in the cold temperatures. The parachute can be tested by dropping the box of a building or some other large height. The adhesive that holds the material together must be tested to see if it can hold together the material even in the extreme temperatures.
After all the tests have been run and all the instruments work properly, the payload can be launched. The balloon will be sent up carrying the payload to about 30 km into the stratosphere. After the balloon reaches its maximum height, the balloon will pop and soon after, the parachute will deploy. The parachute will allow the payload to fall back to the surface and the experimenters will follow and retrieve the payload after it lands. After the entire flight is over, the SD card can be taken from the SD shield and the recorded data can be retrieved. The data can be interpreted and read to find what the experimenters are looking for.