TetherCAD: A Python library to aid in the design of Electromechanical Tethers and Tethered Systems for applications in Robotics and Spacecraft

Tethered robotics offer unique potential to access and operate in harsh terrain and provide power and communication for exploration and infrastructure on the Moon and Mars. The tether is the lifeline for these systems, allowing robots to access impassable terrain features, maintaining power and communication. Their criticality stipulates that they must be designed to survive the harsh environments, while enduring the mechanical and electrical constraints of the systems which deploy them. Designers must perform complex trades to create tethers for their missions, balancing system performance requirements against mass and volume to create viable tethered robotics systems. This paper discusses TetherCAD: a set of tools to aid in high-level design and performance analysis of tethers. TetherCAD helps users create tether solutions that meet their system's unique needs, incorporating length, voltage, losses, power transfer, communications, tensile strength and minimum bend radius to generate tethers that can be fabricated from standard products and are viable for the Lunar and Martian environments. It presents a tether designed using the tools, along with the results of tensile testing over various bend radii and abrasion testing in vacuum, both over a range of Lunar temperatures.