High-altitude scientific balloons are often prohibited from flying due to the risk associated with flying over populated areas. One solution to this problem is the use of a trajectory control system to control the ground track of the balloon. To assess the performance of one such trajectory control system in a real wind field, a small-scale sail was designed and built to fly beneath a moored balloon. Three test phases of rudder deflection were used to demonstrate the effect of the sail guiding force on the balloon, and the sail demonstrated the ability to move the balloon laterally due to a change in rudder deflection. A theoretical model of the system was found to qualitatively agree with the experimental values of sail displacement and mooring tether tension. At a high level, these results demonstrate that a tether-and-sail system shows promise as a trajectory control system for scientific balloons.

高空科学气球通常被禁止飞行，因为有可能会飞过人口稠密的地区。解决该问题的一种方法是使用轨迹控制系统来控制气球的地面轨迹。为了评估一种这样的轨迹控制系统在真实风场中的性能，设计并制造了一种小型帆，使其在系泊的气球下方飞行。方向舵偏转的三个测试阶段用于演示帆引导力对气球的影响，而帆则演示了由于方向舵偏转的变化而使气球横向移动的能力。发现该系统的理论模型在质量上与帆位移和系泊绳索张力的实验值一致。在高层次上，