. . "Electron plasma." . . . . . . . . . . . . . . "\"The Plasma Contactor Units (PCUs) were developed at NASA Glenn Research Center (GRC) and Boeing for charge control on board the International Space Station (ISS). Since the first ignition of a PCU on 10 16 2000 over 3,900 hours of operation have been demonstrated on a single unit. In order to guarantee that the PCUs hollow cathode assemblies (HCAs), which emit the electrons used for charge control, would satisfy the life requirement of 18,000 hours, a ground based hollow cathode life test program was initiated at GRC. The life test program aimed at 27,000 hours of operation on a single unit to demonstrate the industry standard 1.5 times operational life requirement. As of this printing, over 18,000 hours of operation have been accumulated on a single hollow cathode. By comparing the data received from the on-orbit HCAs to the data obtained for the life test cathodes, a comparison may be drawn to determine if the on-orbit HCAs are operating normally, with a final goal of predicting lifetime. Based on the data taken thus far, it can be concluded that the on-orbit HCAs are operating within their design specifications.\""@en . . . . . . . . . . . . . . . . "Comparison of on-orbit and ground based hollow cathode operation"@en . . . . "Space plasmas." . . "Onboard equipment." . . "Cathodes." . . "Contactors." . . "International space station." . . "Ground tests." . . "Electric contactors." . . "Hollow cathodes." . . "Plasma (Ionized gases)" . . "Joint Propulsion Conference and Exhibit (38th : 2002 : Indianapolis, Ind.)" . . .