Cosmic rays are constantly impacting atomic nuclei and other molecules in the upper atmosphere, producing pions. Within meters of traveling, these pions decay into muons and muon neutrinos (Houseman 1999). A muon neutrino is a muon but has a neutral charge, while a muon has a negative charge, just like electrons. These muons have 200 times the mass of an electron but they only interact with the surrounding matter via ionization. The loss of energy by muons passing through the atmosphere is proportional to the amount of matter they traverse (Muon Basics, 2014). These muons travel at 99 percent of the speed of light, which allows them to experience time much slower due to relativity. This allows them to survive longer while in Earth’s frame of reference. These two factors allow them to travel very far into Earth’s atmosphere and sometimes they can even reach the surface (Liu, 2014). On average, 10,000 muons reach every square meter of the Earth’s surface each minute. Since muons do not interact with matter as much as other particles, they are able to penetrate through rocks and other matter before losing their momentum (Muon Basics, 2014). As the muons continue traveling towards Earth, their rate of decay relates directly to altitude. A geiger counter, which will also be on the payload recording data throughout the flight, is a device that detects most types of ionizing radiation, including muons. To measure the altitude, we will be using an altimeter. This altimeter indirectly measures altitude. The altimeter takes measurements of temperature and pressure, and since they are proportional to altitude, the altitude can be derived. With the altimeter measuring the altitude and the geiger counter measuring muon flux their correlation can be determined. The payload will be sent up 30 km into the atmosphere. The geiger counter and altimeter will measure the muon flux and altitude respectively from ground level to 30km. Since the payload is being sent 30 km into the atmosphere, the payload will reach very cold temperatures, so the payload has to be suited for extreme temperatures. At about 30 km up, the temperature will be about -50 degrees Celsius, which means the payload will need to be heated (Russell, 2009). The COSGC (Colorado Space Grant Consortium) that runs the Demosat program set a maximum weight for the payload so the balloon can hold all the modules, from the other schools participating in the program. The payload can only hold 1.5 kg so it can lift all the payloads to 3 km. The payload will have fiberglass insulation on the inside, as well as a heater to keep all the measuring tools heated and working properly. The payload is coated in a layer of aluminum foil to keep the box protected against the elements such as rain, snow, or sleet etc.