Pulsed plasma thruster

The 35-year history of the development and application of the pulsed plasma thruster (PPT) is reviewed, The PPT operates by creating a pulsed, high-cu rrent discharge across the exposed surface of a solid insulator, such as a Teflon(R) bar. The an: discharge ablates material from this surface, thereb y providing propellant that is ionized, heated, and accelerated to high spe ed. Typically, the current pulse lasts for a few microseconds, driven by a capacitor that is charged and discharged approximately once per second. Exh aust speeds range from 3 to 50 km/s, depending on the details of the PPT de sign. We review the basic physics and types of PPTs, and discuss the perfor mance of night and laboratory versions, with special attention to velocity and plume measurements. We also present the status of PPT theory and modeli ng, with emphasis on mass evolution and plasma acceleration, and describe r ecent variations on PPT operation, laboratory thrust measurement techniques , and the separate components of PPT efficiency.