Early results from the floating potential probe on the International Space Station

Summary form only given. In December, 2000, a Floating Potential Probe (FPP) was installed on the International Space Station to monitor the electrical potential of the Space Station relative to the ionospheric plasma ground. This is an independent way to monitor the effectiveness of the plasma contactor, which is designed to maintain the spacecraft´s floating potential within 40 volts of plasma ground. The FPP also has a Langmuir probe, to measure the ambient plasma parameters. We present the early results from the FPP. These include the floating,potential compared to the plasma contactor current, and the plasma parameters compared to IRI-90 models. We also discuss the effectiveness of the plasma contactor at maintaining the floating potential of the Space Station in different configurations.