Unmanned aircraft systems (UASs) and related techniques are provided to improve the operation of unmanned mobile sensor or survey platforms. A tether management system includes a logic device configured to communicate with a communication module and an orientation sensor coupled to a tethered unmanned aerial vehicle (UAV), wherein the communication module is configured to establish a communication link with a base station associated with the tethered UAV, the orientation sensor is configured to provide headings of the tethered UAV as it maneuvers within a survey area. The logic device is configured to determine an accumulated twist of a tether coupled between the base station and the tethered UAV and generate a tether damage warning notification based, at least in part, on the determined accumulated twist and a maximum allowable accumulated twist associated with the tether coupled between the base station and the tethered UAV.