GALCIT Colloquium

Future space missions require precision thrusters for formation flying of multiple spacecraft working in tandem, to high power thrusters for exceptionally rapid (~40 day) transit to Mars. In this talk, Prof. Wirz will discuss the propulsive needs for these missions and recent breakthroughs towards developing thrusters that can meet these needs. For formation flying missions, electrospray thrusters use strong electric fields to extract charged droplets and ions directly from the meniscus of ionic liquids to generate high velocity jets that provide both high propulsive efficiency and thrust precision. However, electrospray thrusters must operate for ~60,000 hours but have yet to demonstrate on-orbit operation over 3500 hours. Recent efforts in Professor Wirz's Plasma & Space Propulsion Laboratory have shown that the high-speed electrohydrodynamics of the droplet and ion extraction and the subsequent Coulombic interactions of these charged particles in the plume can lead to shorting of the high voltage electrodes. Fortunately, this understanding has revealed thruster operating conditions that can prevent such behavior and ensure long thruster lifetimes. On the other hand, for high power thrusters, recent demonstrations of a shear flow stabilized (SFS) Z-pinch fusion device have shown great promise for fusion-based space propulsion. One of the primary challenges of such a thruster is the interaction of the high-density plasma with the nearby electrodes. Professor Wirz will describe recent efforts towards understanding the interaction of plasma ions and electrons with new micro-architectured materials that are particularly robust in the presence of high-temperature plasmas, thus helping to enable this new form of extremely high-power space propulsion.