One of the primary goals of the Tethered Satellite System reflight mission (TSS-1R) is to determine the current-voltage characteristics of the TSS satellite orbiting in the ionosphere. While the collected current was measured directly with high reliability, the satellite potential could only be deduced from a circuit model or from interpretation of measurement data below satellite potentials of 500 Volts. The greatest uncertainty in the circuit model is the value of tether resistance R. We have provided quantitative calibration of the resistance based on instrument data for Vs100 Volts) and low (<10 Volts) voltage regimes, which indicates a fundamental transition for the current collection physics in the ionospheric plasma surrounding the satellite. ¿ 1998 American Geophysical Union