The Voltage output of select solar cells was monitored as a function of altitude up to approximately 93,000 feet. A weather balloon was used to carry the solar cells to the required altitude. Two launches were accomplished to acquire data for analysis. Data collected also included the altitude, temperature and pressure. The voltage signal of the used solar cells depended largely on temperature. It was discovered that the voltage signal of the solar cells has a complex relationship with altitude. Temperature had a significant influence on the magnitude of the voltage signal at lower altitudes, but this influence may have declined at higher altitudes. IntroductionSolar cells have become very popular in many applications, including providing electricity for houses, businesses and some cars. The solar cell industry has grown even faster in the past years due to the increasing demand for alternative sources of energy to fossil fuels. Solar energy is clean and lasts as long as the sun shines. Many researchers are dedicated to increasing the efficiency of solar cells for further applications. NASA's green aviation goals are to support fuel-efficient flight planning and to reduce aircraft fuel consumption, emissions, and noise. NASA's Ames Research Center has been working on reducing carbon footprint around the planet for decades. In addition to the environmental impact, switching to solar energy will have a positive economical influence. For example, the United States government has plans to fly light solar cell-powered drones at high altitudes for days at a time without the need to refuel. Doing this with a conventional plane would be expensive.