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-current discharge across the exposed surface of a solid insulator, such as a Teflon(R) bar. The an: discharge ablates material from this surface, thereby providing propellant that is ionized, heated, and accelerated to high speed. Typically, the current pulse lasts for a few microseconds, driven by a capacitor that is charged and discharged approximately once per second. Exhaust speeds range from 3 to 50 km/s, depending on the details of the PPT design. We review the basic physics and types of PPTs, and discuss the performance of night and laboratory versions, with special attention to velocity and plume measurements. We also present the status of PPT theory and modeling, with emphasis on mass evolution and plasma acceleration, and describe recent variations on PPT operation, laboratory thrust measurement techniques, and the separate components of PPT efficiency.