Current Collection to Electrodynamic-Tether Systems in Space

Three important electrodynamic-tether system configurations have been investigated: an insulated tether with an end body collector, bare tether, and bare tether with end body collector. This paper discusses the current collection capabilities of these configurations and their respective advantages and disadvantages. University of Michigan’s TEMPEST computer model was used to conduct the analyses of the three configurations. Analysis has determined that all three configurations allow orbit raising from 400 km to 700 km in around 18.5 days under similar ionospheric and system conditions. In addition, the best tether geometry to use for any of these configurations would be a slotted tether oriented perpendicular to the plasma flow with the individual wires as far apart as possible and as narrow as possible. This would minimize atmospheric drag, increase collision survivability, and keep the electron collection level close to the orbital-motion limit, while increasing the redundancy of the tether in case of micrometer collision..