Titan Wind Analysis using Lagrangian Coherent Structures

Since 2004, the Cassini-Huygens mission has been providing pictures of Titan's striking landscape of sand dunes and hydrocarbon lakes. Subsequently there have been plans for a return mission involving a Montgolfière balloon or aerobot to be deployed in Titan's thick atmosphere. Lagrangian Coherent Structures are transport barriers separating regions of different dynamical flow, and through their calculation on a wind model for Titan it is possible to identify regions which should be avoided for deployment as well as those which will maximize surface coverage. It is demonstrated that prominent Lagrangian Coherent Structures exist around the North Pole at the anticipated mission arrival time, suggesting that a Montgolfière balloon without horizontal actuation would be trapped if deployed in that region. Secondly, few Lagrangian Coherent Structures exist close to the surface indicating that an aerobot with limited horizontal actuation should descend to low levels to minimize the control effort expended in changing its course.