Testing and Development of the Tethered-Permanently Shadowed Region EXplorer: A Rover Designed to Lay Superconducting Tether into Lunar Permanently Shaded Regions

Document Type


Publication Date



Department of Electrical and Computer Engineering; Department of Computer Science; Department of Mechanical Engineering-Engineering Mechanics


Power and communications are required for successful operations in the permanently shaded regions (PSRs) located at the lunar poles. However, due to the location of PSRs, direct solar power from the Sun and line of sight communications to Earth are limited. NASA solicited solutions from universities within the United States with the Breakthrough, Innovative, and Game-changing (BIG) Idea Challenge. The Planetary Surface Technology Development Lab (PSTDL) at Michigan Technological University (MTU) developed the Tethered-permanently shadowed Region EXplorer (T-REX) to address this problem. A conventional round tether in series with a superconducting tape tether connects to a lander at a crater rim to provide power and communications to T-REX during its descent into a PSR. This mission is enabled by the passive cooling of hardware within the naturally occurring cold environment of a PSR. T-REX was developed by using an iterative approach with testing conducted from component to system-level. System validation included testing within a sloped lunar regolith simulant chamber and component-wise testing under cryogenic temperatures. T-REX has been shown to be capable of traversing down 45° slopes and obstacles in a lunar highland terrain simulant during system mobility testing. The on-board tether deployment system was able to unspool a superconducting tether (SCT) while maintaining controlled rates of under 5 N of tension. A data transfer rate of 94 Mbps via very-high-speed Digital Subscriber Line-2 and 132.2 W of DC power transfer over the SCT when cooled to 77 K was validated through testing. Thermal analyses on the system analytically validated the performance of T-REX during the transition between shaded and illuminated regions. The T-REX rover technology was raised to Technology Readiness Level 5 over 1.5 years of research. The SCTs are high-efficiency, low mass means of providing power and data in extreme lunar environments.

Publication Title

New Space