Experimental and theoretical modeling of a wind driven sensor platform for Martian surface exploration

In this thesis, the groundwork is laid for modeling the dynamics of a new concept in Martian surface exploration. The concept, called the Texas Tech Tumbleweed, is a completely passive device that is intended to be deployed in large numbers over the Martian surface. Testing of the validity of the concept is the primary focus of this work. Extensive wind tunnel testing was performed on the device in order to determine its drag characteristics in any orientation relative to the wind. Prior to testing the tumbleweed concept, a verification of the test setup was performed using flat plate and sphere models whose results were compared to those found in the literature. The test setup was found to produce results accurate within 5% for these models.

The results obtained from the wind tunnel testing were then used as the force model in a dynamic model to predict the behavior of the device in a simulated Martian environment. The model presented here was developed using a variational approach, has a no-slip condition enforced at the contact point, and is not allowed to leave the surface. Results from the dynamic simulations are shown to predict that the tumbleweed concept will be mobile in the Martian environment on level ground. Further investigation of the mobility of the tumbleweed when introduced to an inclination was performed with simple hand calculations, and the results will be shown.