Constructing Solar and Zero Pressure High Altitude Balloons

Abstract:

High altitude ballooning has been a means of studying near space environments since the late 1700’s. The most popular method for these flights have been latex balloons, which are typically filled with helium and burst upon reaching their maximum altitude. While this method often reaches altitudes upwards of 30,000 meters, because the balloon will burst, the data that can be collected is limited. Therefore, we are interested in alternative methods of high altitude ballooning.

This project specifically examined solar and zero pressure balloons. In particular, we tested whether or not these types can be efficiently manufactured by an academic ballooning team. To prepare for this project, previous methods were studied from other laboratories, especially a gore design from Raven Aerostar. Gores are the individual plastic panels that are seamed together to create a balloon. We constructed the gores with thin-film plastic and sealed them together with a portable heat sealer. Strong seals are important because at a specific altitude, the balloon’s internal pressure is equal to that of the outside. Therefore, if no leaks are present, this equilibrium allows the balloon to float for hours at a time. Solar balloons are especially interesting for academic ballooning programs because they are darkened and thus need no helium to rise, instead relying on temperature differences between the inside and the outside of the balloon to generate lift.

After construction, we launched the solar and zero pressure balloons and let them float for nearly an hour. The flights were recorded by an Iridium GPS tracking system and various GoPro cameras. Each flight proved successful as both balloons attained their predicted altitude and remained at float with minimal elevation loss. This indicates the seams held together with only a few leaks and in the case of the solar balloon, a suitable internal temperature was reached. Our results show that with careful construction, plastic balloons can be built to float at a specific altitude. Lessons learned from this project will help future students better design and construct their own balloons. The presentation will further explain our results as well as the planning process and how the balloons were constructed.