<div align="left" style="font-size: 12px; font-family: Arial, Helvetica, sans-serif">Space Instrumentation Lab</div>

Floating Potential Measurement Unit (FPMU)

In collaboration with Utah State University, SDL developed the Floating Potential Measurement Unit (FPMU), which was installed on the International Space Station (ISS) for the NASA Johnson Space Center on August 3, 2006. The probe is based on past USU/SDL space instruments and incorporates a Floating Potential Probe, multiple Langmuir Probes, and a Plasma Frequency Probe into one sensor suite. The FPMU will be used to monitor ISS charging so that steps can be taken to provide a safer environment for the astronauts during Extra Vehicular Activities (EVA).

The FPMU program was a fast response effort by SDL to help NASA understand the charging physics of the ISS. The FPMU will be used to correct the charging models of the station each time a new section is added to the structure. By providing feedback on the effectiveness of steps taken to control charging, the FPMU will help ensure a safe working environment for the astronauts.